feat: interval& None value for prev&`next (#252)

* test: for builtin functions

* test: expect fail for `datetime()`

* feat: add `interval()` fn(WIP)

* feat: `interval()` fn in builtin(UNTEST)

* refactor: move `py_vec_obj_to_array` to util.rs

* style: fmt

* test: simple `interval()` cases

* test: `interval()` with `last()`&`first()`

* doc: `ts` param of `interval()`

* log: common_telemetry for logging in script crate

* doc: corrsponding test fn for each .ron file

* feat: change to`mpsc` for schedule_job

* test: schedule_job

* dep: rm rustpython dep in common-function

* refactor: mv `schedule_job` into `Script` trait

* test: change to use `interval` to sample datapoint

* feat: add gen_none_array for generate None Array

* feat: impl Missing value for `prev`&`next`

* test: `sum(prev(values))`

* doc: add comment for why not support Float16 in `prev()`

* feat: add `interval` in py side mock module

* style: cargo fmt

* refactor: according to comments

* refactor: extract `apply_interval_function`

* style: cargo fmt

* refactor: remove `schedule()`

* style: cargo fmt

Cargo.lock

@@ -838,12 +838,6 @@ dependencies = [
  "once_cell",
  "paste",
  "ron",
- "rustpython-ast",
- "rustpython-bytecode",
- "rustpython-compiler",
- "rustpython-compiler-core",
- "rustpython-parser",
- "rustpython-vm",
  "serde",
  "snafu",
  "statrs",
@@ -4440,6 +4434,7 @@ dependencies = [
  "datatypes",
  "futures",
  "futures-util",
+ "paste",
  "log-store",
  "query",
  "ron",

component/script/python/example/calc_rv.py

@@ -44,13 +44,15 @@ def as_table(kline: list):
     "rv_60d",
     "rv_90d",
     "rv_180d"
-],
-sql="select open_time, close from k_line")
+])
 def calc_rvs(open_time, close):
-    from greptime import vector, log, prev, sqrt, datetime, pow, sum
+    from greptime import vector, log, prev, sqrt, datetime, pow, sum, last
+    import greptime as g
     def calc_rv(close, open_time, time, interval):
         mask = (open_time < time) & (open_time > time - interval)
         close = close[mask]
+        open_time = open_time[mask]
+        close = g.interval(open_time, close, datetime("10m"), lambda x:last(x))
 
         avg_time_interval = (open_time[-1] - open_time[0])/(len(open_time)-1)
         ref = log(close/prev(close))
@@ -60,10 +62,10 @@ def calc_rvs(open_time, close):
     # how to get env var,
     # maybe through accessing scope and serde then send to remote?
     timepoint = open_time[-1]
-    rv_7d = calc_rv(close, open_time, timepoint, datetime("7d"))
-    rv_15d = calc_rv(close, open_time, timepoint, datetime("15d"))
-    rv_30d = calc_rv(close, open_time, timepoint, datetime("30d"))
-    rv_60d = calc_rv(close, open_time, timepoint, datetime("60d"))
-    rv_90d = calc_rv(close, open_time, timepoint, datetime("90d"))
-    rv_180d = calc_rv(close, open_time, timepoint, datetime("180d"))
+    rv_7d = vector([calc_rv(close, open_time, timepoint, datetime("7d"))])
+    rv_15d = vector([calc_rv(close, open_time, timepoint, datetime("15d"))])
+    rv_30d = vector([calc_rv(close, open_time, timepoint, datetime("30d"))])
+    rv_60d = vector([calc_rv(close, open_time, timepoint, datetime("60d"))])
+    rv_90d = vector([calc_rv(close, open_time, timepoint, datetime("90d"))])
+    rv_180d = vector([calc_rv(close, open_time, timepoint, datetime("180d"))])
     return rv_7d, rv_15d, rv_30d, rv_60d, rv_90d, rv_180d

component/script/python/example/kline.json

@@ -7,7 +7,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231300,
+            "open_time": 300,
             "open": "10107",
             "high": "10109.34",
             "low": "10106.71",
@@ -16,7 +16,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231360,
+            "open_time": 900,
             "open": "10106.79",
             "high": "10109.27",
             "low": "10105.92",
@@ -25,7 +25,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231420,
+            "open_time": 1200,
             "open": "10106.09",
             "high": "10108.75",
             "low": "10104.66",
@@ -34,7 +34,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231480,
+            "open_time": 1800,
             "open": "10108.73",
             "high": "10109.52",
             "low": "10106.07",
@@ -43,7 +43,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231540,
+            "open_time": 2400,
             "open": "10106.38",
             "high": "10109.48",
             "low": "10104.81",
@@ -52,7 +52,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231600,
+            "open_time": 3000,
             "open": "10106.95",
             "high": "10109.48",
             "low": "10106.6",
@@ -61,7 +61,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231660,
+            "open_time": 3600,
             "open": "10107.55",
             "high": "10109.28",
             "low": "10104.68",
@@ -70,7 +70,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231720,
+            "open_time": 4200,
             "open": "10104.68",
             "high": "10109.18",
             "low": "10104.14",
@@ -79,7 +79,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231780,
+            "open_time": 4800,
             "open": "10108.8",
             "high": "10117.36",
             "low": "10108.8",
@@ -88,7 +88,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231840,
+            "open_time": 5400,
             "open": "10115.96",
             "high": "10119.19",
             "low": "10115.96",
@@ -97,7 +97,7 @@
         {
             "symbol": "BTCUSD",
             "period": "1",
-            "open_time": 1581231900,
+            "open_time": 6000,
             "open": "10117.08",
             "high": "10120.73",
             "low": "10116.96",

component/script/python/greptime/__init__.py

@@ -1,4 +1,4 @@
 from .greptime import coprocessor, copr
-from .greptime import vector, log, prev, sqrt, pow, datetime, sum
+from .greptime import vector, log, prev, next, first, last, sqrt, pow, datetime, sum, interval
 from .mock import mock_tester
 from .cfg import set_conn_addr, get_conn_addr

component/script/python/greptime/greptime.py

@@ -89,6 +89,11 @@ class vector(np.ndarray):
     def filter(self, lst_bool):
         return self[lst_bool]
 
+def last(lst):
+    return lst[-1]
+
+def first(lst):
+    return lst[0]
 
 def prev(lst):
     ret = np.zeros(len(lst))
@@ -96,35 +101,22 @@ def prev(lst):
     ret[0] = nan
     return ret
 
+def next(lst):
+    ret = np.zeros(len(lst))
+    ret[:-1] = lst[1:]
+    ret[-1] = nan
+    return ret
 
-def query(sql: str):
-    pass
-
-
-def interval(arr: list, duration: int, fill, step: None | int = None, explicitOffset=False):
+def interval(ts: vector, arr: vector, duration: int, func):
     """
     Note that this is a mock function with same functionailty to the actual Python Coprocessor
     `arr` is a vector of integral or temporal type.
-
-    `duration` is the length of sliding window
-
-    `step` being the length when sliding window take a step
-
-    `fill` indicate how to fill missing value:
-    - "prev": use previous
-    - "post": next
-    - "linear": linear interpolation, if not possible to interpolate certain types, fallback to prev
-    - "null": use null
-    - "none": do not interpolate
     """
-    if step is None:
-        step = duration
-
-    tot_len = int(np.ceil(len(arr) // step))
-    slices = np.zeros((tot_len, int(duration)))
-    for idx, start in enumerate(range(0, len(arr), step)):
-        slices[idx] = arr[start:(start + duration)]
-    return slices
+    start = np.min(ts)
+    end = np.max(ts)
+    masks = [(ts >= i) & (ts <= (i+duration)) for i in range(start, end, duration)]
+    lst_res = [func(arr[mask]) for mask in masks]
+    return lst_res
 
 
 def factor(unit: str) -> int:

component/script/python/greptime/mock.py

@@ -4,7 +4,7 @@ it can only run on mock data and support by numpy
 """
 from typing import Any
 import numpy as np
-from .greptime import i32,i64,f32,f64, vector, interval, query, prev, datetime, log, sum, sqrt, pow, nan, copr, coprocessor
+from .greptime import i32,i64,f32,f64, vector, interval, prev, datetime, log, sum, sqrt, pow, nan, copr, coprocessor
 
 import inspect
 import functools

component/script/python/test.py

@@ -26,6 +26,16 @@ def get_db(req:str):
     return requests.get("http://{}{}".format(get_conn_addr(), req))
 
 if __name__ == "__main__":
+    with open("component/script/python/example/kline.json", "r") as kline_file:
+        kline = json.load(kline_file)
+        table = as_table(kline["result"])
+        close = table["close"]
+        open_time = table["open_time"]
+        env = {"close":close, "open_time": open_time}
+
+        res = mock_tester(calc_rvs, env=env)
+        print("Mock result:", [i[0] for i in res])
+        exit()
     if len(sys.argv)!=2:
         raise Exception("Expect only one address as cmd's args")
     set_conn_addr(sys.argv[1])
@@ -42,11 +52,6 @@ if __name__ == "__main__":
         open_time = table["open_time"]
         init_table(close, open_time)
 
-        # print(repr(close), repr(open_time))
-        # print("calc_rv:", calc_rv(close, open_time, open_time[-1]+datetime("10m"), datetime("7d")))
-        env = {"close":close, "open_time": open_time}
-        # print("env:", env)
-        print("Mock result:", mock_tester(calc_rvs, env=env))
         real = calc_rvs()
         print(real)
         try:

src/common/function/Cargo.toml

@@ -21,12 +21,6 @@ num = "0.4"
 num-traits = "0.2"
 once_cell = "1.10"
 paste = "1.0"
-rustpython-ast = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
-rustpython-bytecode = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
-rustpython-compiler = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
-rustpython-compiler-core = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
-rustpython-parser = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
-rustpython-vm = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
 snafu = { version = "0.7", features = ["backtraces"] }
 statrs = "0.15"
 

src/script/Cargo.toml

@@ -15,6 +15,7 @@ python = [
   "dep:rustpython-compiler-core",
   "dep:rustpython-bytecode",
   "dep:rustpython-ast",
+  "dep:paste"
 ]
 
 [dependencies]
@@ -41,8 +42,10 @@ rustpython-compiler = {git = "https://github.com/RustPython/RustPython", optiona
 rustpython-compiler-core = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
 rustpython-parser = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
 rustpython-vm = {git = "https://github.com/RustPython/RustPython", optional = true, rev = "02a1d1d"}
+paste = { version = "1.0", optional = true}
 snafu = {version = "0.7", features = ["backtraces"]}
 sql = { path = "../sql" }
+tokio = { version = "1.0", features = ["full"] }
 table = { path = "../table" }
 
 [dev-dependencies]

src/script/src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(iterator_try_reduce)]
 pub mod engine;
 pub mod error;
 #[cfg(feature = "python")]

src/script/src/python/builtins/mod.rs

@@ -1,4 +1,5 @@
 //!  Builtin module contains GreptimeDB builtin udf/udaf
+
 #[cfg(test)]
 #[allow(clippy::print_stdout)]
 mod test;
@@ -271,6 +272,10 @@ pub(crate) mod greptime_builtin {
 
     use common_function::scalars::math::PowFunction;
     use common_function::scalars::{function::FunctionContext, Function};
+    use datafusion::arrow::compute::comparison::{gt_eq_scalar, lt_eq_scalar};
+    use datafusion::arrow::datatypes::DataType;
+    use datafusion::arrow::error::ArrowError;
+    use datafusion::arrow::scalar::{PrimitiveScalar, Scalar};
     use datafusion::physical_plan::expressions;
     use datafusion_expr::ColumnarValue as DFColValue;
     use datafusion_physical_expr::math_expressions;
@@ -278,16 +283,17 @@ pub(crate) mod greptime_builtin {
     use datatypes::arrow::array::{ArrayRef, NullArray};
     use datatypes::arrow::compute;
     use datatypes::vectors::{ConstantVector, Float64Vector, Helper, Int64Vector};
-    use rustpython_vm::builtins::{PyFloat, PyInt, PyStr};
-    use rustpython_vm::function::OptionalArg;
-    use rustpython_vm::{AsObject, PyObjectRef, PyResult, VirtualMachine};
+    use paste::paste;
+    use rustpython_vm::builtins::{PyFloat, PyFunction, PyInt, PyStr};
+    use rustpython_vm::function::{FuncArgs, KwArgs, OptionalArg};
+    use rustpython_vm::{AsObject, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine};
 
     use crate::python::builtins::{
         all_to_f64, eval_aggr_fn, from_df_err, try_into_columnar_value, try_into_py_obj,
         type_cast_error,
     };
-    use crate::python::utils::is_instance;
     use crate::python::utils::PyVectorRef;
+    use crate::python::utils::{is_instance, py_vec_obj_to_array};
     use crate::python::PyVector;
 
     #[pyfunction]
@@ -655,23 +661,48 @@ pub(crate) mod greptime_builtin {
         let args = vec![base.as_vector_ref(), arg_pow];
         let res = PowFunction::default()
             .eval(FunctionContext::default(), &args)
-            .unwrap();
+            .map_err(|err| {
+                vm.new_runtime_error(format!(
+                    "Fail to eval pow() withi given args: {args:?}, Error: {err}"
+                ))
+            })?;
         Ok(res.into())
     }
 
-    // TODO: prev, sum, pow, sqrt, datetime, slice, and filter(through boolean array)
+    fn gen_none_array(data_type: DataType, len: usize, vm: &VirtualMachine) -> PyResult<ArrayRef> {
+        macro_rules! match_none_array {
+            ($VAR:ident, $LEN: ident, [$($TY:ident),*]) => {
+                paste!{
+                    match $VAR{
+                        $(DataType::$TY => Arc::new(arrow::array::[<$TY Array>]::from(vec![None;$LEN])), )*
+                        _ => return Err(vm.new_type_error(format!("gen_none_array() does not support {:?}", data_type)))
+                    }
+                }
+            };
+        }
+        let ret: ArrayRef = match_none_array!(
+            data_type,
+            len,
+            [Boolean, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Float32, Float64] // We don't support float16 right now, it's not common in usage.
+        );
+        Ok(ret)
+    }
 
-    /// TODO: for now prev(arr)[0] == arr[0], need better fill method
     #[pyfunction]
     fn prev(cur: PyVectorRef, vm: &VirtualMachine) -> PyResult<PyVector> {
         let cur: ArrayRef = cur.to_arrow_array();
         if cur.len() == 0 {
-            return Err(
-                vm.new_runtime_error("Can't give prev for a zero length array!".to_string())
-            );
+            let ret = cur.slice(0, 0);
+            let ret = Helper::try_into_vector(&*ret).map_err(|e| {
+                vm.new_type_error(format!(
+                    "Can't cast result into vector, result: {:?}, err: {:?}",
+                    ret, e
+                ))
+            })?;
+            return Ok(ret.into());
         }
         let cur = cur.slice(0, cur.len() - 1); // except the last one that is
-        let fill = cur.slice(0, 1);
+        let fill = gen_none_array(cur.data_type().to_owned(), 1, vm)?;
         let ret = compute::concatenate::concatenate(&[&*fill, &*cur]).map_err(|err| {
             vm.new_runtime_error(format!("Can't concat array[0] with array[0:-1]!{err:#?}"))
         })?;
@@ -684,6 +715,211 @@ pub(crate) mod greptime_builtin {
         Ok(ret.into())
     }
 
+    #[pyfunction]
+    fn next(cur: PyVectorRef, vm: &VirtualMachine) -> PyResult<PyVector> {
+        let cur: ArrayRef = cur.to_arrow_array();
+        if cur.len() == 0 {
+            let ret = cur.slice(0, 0);
+            let ret = Helper::try_into_vector(&*ret).map_err(|e| {
+                vm.new_type_error(format!(
+                    "Can't cast result into vector, result: {:?}, err: {:?}",
+                    ret, e
+                ))
+            })?;
+            return Ok(ret.into());
+        }
+        let cur = cur.slice(1, cur.len() - 1); // except the last one that is
+        let fill = gen_none_array(cur.data_type().to_owned(), 1, vm)?;
+        let ret = compute::concatenate::concatenate(&[&*cur, &*fill]).map_err(|err| {
+            vm.new_runtime_error(format!("Can't concat array[0] with array[0:-1]!{err:#?}"))
+        })?;
+        let ret = Helper::try_into_vector(&*ret).map_err(|e| {
+            vm.new_type_error(format!(
+                "Can't cast result into vector, result: {:?}, err: {:?}",
+                ret, e
+            ))
+        })?;
+        Ok(ret.into())
+    }
+
+    fn try_scalar_to_value(scalar: &dyn Scalar, vm: &VirtualMachine) -> PyResult<i64> {
+        let ty_error = |s: String| vm.new_type_error(s);
+        scalar
+            .as_any()
+            .downcast_ref::<PrimitiveScalar<i64>>()
+            .ok_or_else(|| {
+                ty_error(format!(
+                    "expect scalar to be i64, found{:?}",
+                    scalar.data_type()
+                ))
+            })?
+            .value()
+            .ok_or_else(|| ty_error("All element is Null in a time series array".to_string()))
+    }
+
+    /// generate interval time point
+    fn gen_inteveral(
+        oldest: &dyn Scalar,
+        newest: &dyn Scalar,
+        duration: i64,
+        vm: &VirtualMachine,
+    ) -> PyResult<Vec<PrimitiveScalar<i64>>> {
+        use arrow::datatypes::DataType;
+        match (oldest.data_type(), newest.data_type()) {
+            (DataType::Int64, DataType::Int64) => (),
+            _ => {
+                return Err(vm.new_type_error(format!(
+                    "Expect int64, found {:?} and {:?}",
+                    oldest.data_type(),
+                    newest.data_type()
+                )));
+            }
+        }
+
+        let oldest = try_scalar_to_value(oldest, vm)?;
+        let newest = try_scalar_to_value(newest, vm)?;
+        if oldest > newest {
+            return Err(vm.new_value_error(format!("{oldest} is greater than {newest}")));
+        }
+        let ret = if duration > 0 {
+            (oldest..=newest)
+                .step_by(duration as usize)
+                .map(|v| PrimitiveScalar::new(DataType::Int64, Some(v)))
+                .collect::<Vec<_>>()
+        } else {
+            return Err(vm.new_value_error(format!("duration: {duration} is not positive number.")));
+        };
+
+        Ok(ret)
+    }
+
+    /// `func`: exec on sliding window slice of given `arr`, expect it to always return a PyVector of one element
+    /// `ts`: a vector of time stamp, expect to be Monotonous increase
+    /// `arr`: actual data vector
+    /// `duration`: the size of sliding window, also is the default step of sliding window's per step
+    #[pyfunction]
+    fn interval(
+        ts: PyVectorRef,
+        arr: PyVectorRef,
+        duration: i64,
+        func: PyRef<PyFunction>,
+        vm: &VirtualMachine,
+    ) -> PyResult<PyVector> {
+        // TODO(discord9): change to use PyDict to mimic a table?
+        // then: table: PyDict, , lambda t:
+        // ts: PyStr, duration: i64
+        // TODO: try to return a PyVector if possible, using concat array in arrow's compute module
+        // 1. slice them according to duration
+        let arrow_error = |err: ArrowError| vm.new_runtime_error(format!("Arrow Error: {err:#?}"));
+        let datatype_error =
+            |err: datatypes::Error| vm.new_runtime_error(format!("DataType Errors!: {err:#?}"));
+        let ts: ArrayRef = ts.to_arrow_array();
+        let arr: ArrayRef = arr.to_arrow_array();
+        let slices = {
+            let oldest = compute::aggregate::min(&*ts).map_err(arrow_error)?;
+            let newest = compute::aggregate::max(&*ts).map_err(arrow_error)?;
+            gen_inteveral(&*oldest, &*newest, duration, vm)?
+        };
+
+        let windows = {
+            slices
+                .iter()
+                .zip({
+                    let mut it = slices.iter();
+                    it.next();
+                    it
+                })
+                .map(|(first, second)| {
+                    compute::boolean::and(&gt_eq_scalar(&*ts, first), &lt_eq_scalar(&*ts, second))
+                        .map_err(arrow_error)
+                })
+                .map(|mask| match mask {
+                    Ok(mask) => compute::filter::filter(&*arr, &mask).map_err(arrow_error),
+                    Err(e) => Err(e),
+                })
+                .collect::<Result<Vec<_>, _>>()?
+        };
+
+        let apply_interval_function = |v: PyResult<PyVector>| match v {
+            Ok(v) => {
+                let args = FuncArgs::new(vec![v.into_pyobject(vm)], KwArgs::default());
+                let ret = func.invoke(args, vm);
+                match ret{
+                        Ok(obj) => match py_vec_obj_to_array(&obj, vm, 1){
+                            Ok(v) => if v.len()==1{
+                                Ok(v)
+                            }else{
+                                Err(vm.new_runtime_error(format!("Expect return's length to be at most one, found to be length of {}.", v.len())))
+                            },
+                            Err(err) => Err(vm
+                                .new_runtime_error(
+                                    format!("expect `interval()`'s `func` return a PyVector(`vector`) or int/float/bool, found return to be {:?}, error msg: {err}", obj)
+                                )
+                            )
+                        }
+                        Err(e) => Err(e),
+                    }
+            }
+            Err(e) => Err(e),
+        };
+
+        // 2. apply function on each slice
+        let fn_results = windows
+            .into_iter()
+            .map(|window| {
+                Helper::try_into_vector(window)
+                    .map(PyVector::from)
+                    .map_err(datatype_error)
+            })
+            .map(apply_interval_function)
+            .collect::<Result<Vec<_>, _>>()?;
+
+        // 3. get returen vector and concat them
+        let ret = fn_results
+            .into_iter()
+            .try_reduce(|acc, x| {
+                compute::concatenate::concatenate(&[acc.as_ref(), x.as_ref()]).map(Arc::from)
+            })
+            .map_err(arrow_error)?
+            .unwrap_or_else(|| Arc::from(arr.slice(0, 0)));
+        // 4. return result vector
+        Ok(Helper::try_into_vector(ret).map_err(datatype_error)?.into())
+    }
+
+    /// return first element in a `PyVector` in sliced new `PyVector`, if vector's length is zero, return a zero sized slice instead
+    #[pyfunction]
+    fn first(arr: PyVectorRef, vm: &VirtualMachine) -> PyResult<PyVector> {
+        let arr: ArrayRef = arr.to_arrow_array();
+        let ret = match arr.len() {
+            0 => arr.slice(0, 0),
+            _ => arr.slice(0, 1),
+        };
+        let ret = Helper::try_into_vector(&*ret).map_err(|e| {
+            vm.new_type_error(format!(
+                "Can't cast result into vector, result: {:?}, err: {:?}",
+                ret, e
+            ))
+        })?;
+        Ok(ret.into())
+    }
+
+    /// return last element in a `PyVector` in sliced new `PyVector`, if vector's length is zero, return a zero sized slice instead
+    #[pyfunction]
+    fn last(arr: PyVectorRef, vm: &VirtualMachine) -> PyResult<PyVector> {
+        let arr: ArrayRef = arr.to_arrow_array();
+        let ret = match arr.len() {
+            0 => arr.slice(0, 0),
+            _ => arr.slice(arr.len() - 1, 1),
+        };
+        let ret = Helper::try_into_vector(&*ret).map_err(|e| {
+            vm.new_type_error(format!(
+                "Can't cast result into vector, result: {:?}, err: {:?}",
+                ret, e
+            ))
+        })?;
+        Ok(ret.into())
+    }
+
     #[pyfunction]
     fn datetime(input: &PyStr, vm: &VirtualMachine) -> PyResult<i64> {
         let mut parsed = Vec::new();

src/script/src/python/builtins/test.rs

@@ -1,10 +1,25 @@
-use std::sync::Arc;
+use std::{collections::HashMap, fs::File, io::Read, path::Path, sync::Arc};
 
-use arrow::array::PrimitiveArray;
+use arrow::{
+    array::{Float64Array, Int64Array, PrimitiveArray},
+    compute::cast::CastOptions,
+    datatypes::DataType,
+};
+use datatypes::vectors::VectorRef;
+use ron::from_str as from_ron_string;
 use rustpython_vm::class::PyClassImpl;
+use rustpython_vm::{
+    builtins::{PyFloat, PyInt, PyList},
+    convert::ToPyObject,
+    scope::Scope,
+    AsObject, PyObjectRef, VirtualMachine,
+};
+use serde::{Deserialize, Serialize};
 
+use super::greptime_builtin;
 use super::*;
 use crate::python::utils::format_py_error;
+use crate::python::{utils::is_instance, PyVector};
 #[test]
 fn convert_scalar_to_py_obj_and_back() {
     rustpython_vm::Interpreter::with_init(Default::default(), |vm| {
@@ -75,3 +90,384 @@ fn convert_scalar_to_py_obj_and_back() {
         assert!(expect_err.is_err());
     })
 }
+
+#[derive(Debug, Serialize, Deserialize)]
+struct TestCase {
+    input: HashMap<String, Var>,
+    script: String,
+    expect: Result<Var, String>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct Var {
+    value: PyValue,
+    ty: DataType,
+}
+
+/// for floating number comparsion
+const EPS: f64 = 2.0 * f64::EPSILON;
+
+/// Null element just not supported for now for simplicity with writing test cases
+#[derive(Debug, Serialize, Deserialize)]
+enum PyValue {
+    FloatVec(Vec<f64>),
+    FloatVecWithNull(Vec<Option<f64>>),
+    IntVec(Vec<i64>),
+    IntVecWithNull(Vec<Option<i64>>),
+    Int(i64),
+    Float(f64),
+    Bool(bool),
+    Str(String),
+    /// for test if the length of FloatVec is of the same as `LenFloatVec.0`
+    LenFloatVec(usize),
+    /// for test if the length of IntVec is of the same as `LenIntVec.0`
+    LenIntVec(usize),
+    /// for test if result is within the bound of err using formula:
+    /// `(res - value).abs() < (value.abs()* error_percent)`
+    FloatWithError {
+        value: f64,
+        error_percent: f64,
+    },
+}
+
+impl PyValue {
+    /// compare if results is just as expect, not using PartialEq because it is not transtive .e.g. [1,2,3] == len(3) == [4,5,6]
+    fn just_as_expect(&self, other: &Self) -> bool {
+        match (self, other) {
+            (PyValue::FloatVec(a), PyValue::FloatVec(b)) => a
+                .iter()
+                .zip(b)
+                .fold(true, |acc, (x, y)| acc && (x - y).abs() <= EPS),
+
+            (Self::FloatVecWithNull(a), Self::FloatVecWithNull(b)) => a == b,
+
+            (PyValue::IntVec(a), PyValue::IntVec(b)) => a == b,
+
+            (PyValue::Float(a), PyValue::Float(b)) => (a - b).abs() <= EPS,
+
+            (PyValue::Int(a), PyValue::Int(b)) => a == b,
+
+            // for just compare the length of vector
+            (PyValue::LenFloatVec(len), PyValue::FloatVec(v)) => *len == v.len(),
+
+            (PyValue::LenIntVec(len), PyValue::IntVec(v)) => *len == v.len(),
+
+            (PyValue::FloatVec(v), PyValue::LenFloatVec(len)) => *len == v.len(),
+
+            (PyValue::IntVec(v), PyValue::LenIntVec(len)) => *len == v.len(),
+
+            (
+                Self::Float(v),
+                Self::FloatWithError {
+                    value,
+                    error_percent,
+                },
+            )
+            | (
+                Self::FloatWithError {
+                    value,
+                    error_percent,
+                },
+                Self::Float(v),
+            ) => (v - value).abs() < (value.abs() * error_percent),
+            (_, _) => false,
+        }
+    }
+}
+
+fn is_float(ty: &DataType) -> bool {
+    matches!(
+        ty,
+        DataType::Float16 | DataType::Float32 | DataType::Float64
+    )
+}
+
+/// unsigned included
+fn is_int(ty: &DataType) -> bool {
+    matches!(
+        ty,
+        DataType::UInt8
+            | DataType::UInt16
+            | DataType::UInt32
+            | DataType::UInt64
+            | DataType::Int8
+            | DataType::Int16
+            | DataType::Int32
+            | DataType::Int64
+    )
+}
+
+impl PyValue {
+    fn to_py_obj(&self, vm: &VirtualMachine) -> Result<PyObjectRef, String> {
+        let v: VectorRef = match self {
+            PyValue::FloatVec(v) => {
+                Arc::new(datatypes::vectors::Float64Vector::from_vec(v.clone()))
+            }
+            PyValue::IntVec(v) => Arc::new(datatypes::vectors::Int64Vector::from_vec(v.clone())),
+            PyValue::Int(v) => return Ok(vm.ctx.new_int(*v).into()),
+            PyValue::Float(v) => return Ok(vm.ctx.new_float(*v).into()),
+            Self::Bool(v) => return Ok(vm.ctx.new_bool(*v).into()),
+            Self::Str(s) => return Ok(vm.ctx.new_str(s.as_str()).into()),
+            _ => return Err(format!("Unsupported type:{self:#?}")),
+        };
+        let v = PyVector::from(v).to_pyobject(vm);
+        Ok(v)
+    }
+
+    fn from_py_obj(obj: &PyObjectRef, vm: &VirtualMachine) -> Result<Self, String> {
+        if is_instance::<PyVector>(obj, vm) {
+            let res = obj.payload::<PyVector>().unwrap();
+            let res = res.to_arrow_array();
+            let ty = res.data_type();
+            if is_float(ty) {
+                let vec_f64 = arrow::compute::cast::cast(
+                    res.as_ref(),
+                    &DataType::Float64,
+                    CastOptions {
+                        wrapped: true,
+                        partial: true,
+                    },
+                )
+                .map_err(|err| format!("{err:#?}"))?;
+                assert_eq!(vec_f64.data_type(), &DataType::Float64);
+                let vec_f64 = vec_f64
+                    .as_any()
+                    .downcast_ref::<Float64Array>()
+                    .ok_or(format!("Can't cast {vec_f64:#?} to Float64Array!"))?;
+                let ret = vec_f64
+                    .into_iter()
+                    .map(|v| v.map(|inner| inner.to_owned()))
+                    /* .enumerate()
+                    .map(|(idx, v)| {
+                        v.ok_or(format!(
+                            "No null element expected, found one in {idx} position"
+                        ))
+                        .map(|v| v.to_owned())
+                    })*/
+                    .collect::<Vec<_>>();
+                if ret.iter().all(|x| x.is_some()) {
+                    Ok(Self::FloatVec(
+                        ret.into_iter().map(|i| i.unwrap()).collect(),
+                    ))
+                } else {
+                    Ok(Self::FloatVecWithNull(ret))
+                }
+            } else if is_int(ty) {
+                let vec_int = arrow::compute::cast::cast(
+                    res.as_ref(),
+                    &DataType::Int64,
+                    CastOptions {
+                        wrapped: true,
+                        partial: true,
+                    },
+                )
+                .map_err(|err| format!("{err:#?}"))?;
+                assert_eq!(vec_int.data_type(), &DataType::Int64);
+                let vec_i64 = vec_int
+                    .as_any()
+                    .downcast_ref::<Int64Array>()
+                    .ok_or(format!("Can't cast {vec_int:#?} to Int64Array!"))?;
+                let ret: Vec<i64> = vec_i64
+                    .into_iter()
+                    .enumerate()
+                    .map(|(idx, v)| {
+                        v.ok_or(format!(
+                            "No null element expected, found one in {idx} position"
+                        ))
+                        .map(|v| v.to_owned())
+                    })
+                    .collect::<Result<_, String>>()?;
+                Ok(Self::IntVec(ret))
+            } else {
+                Err(format!("unspupported DataType:{ty:#?}"))
+            }
+        } else if is_instance::<PyInt>(obj, vm) {
+            let res = obj
+                .to_owned()
+                .try_into_value::<i64>(vm)
+                .map_err(|err| format_py_error(err, vm).to_string())?;
+            Ok(Self::Int(res))
+        } else if is_instance::<PyFloat>(obj, vm) {
+            let res = obj
+                .to_owned()
+                .try_into_value::<f64>(vm)
+                .map_err(|err| format_py_error(err, vm).to_string())?;
+            Ok(Self::Float(res))
+        } else if is_instance::<PyList>(obj, vm) {
+            let res = obj.payload::<PyList>().unwrap();
+            let res: Vec<f64> = res
+                .borrow_vec()
+                .iter()
+                .map(|obj| {
+                    let res = Self::from_py_obj(obj, vm).unwrap();
+                    assert!(matches!(res, Self::Float(_) | Self::Int(_)));
+                    match res {
+                        Self::Float(v) => Ok(v),
+                        Self::Int(v) => Ok(v as f64),
+                        _ => Err(format!("Expect only int/float in list, found {res:#?}")),
+                    }
+                })
+                .collect::<Result<_, _>>()?;
+            Ok(Self::FloatVec(res))
+        } else {
+            todo!()
+        }
+    }
+}
+
+#[test]
+fn run_builtin_fn_testcases() {
+    let loc = Path::new("src/python/builtins/testcases.ron");
+    let loc = loc.to_str().expect("Fail to parse path");
+    let mut file = File::open(loc).expect("Fail to open file");
+    let mut buf = String::new();
+    file.read_to_string(&mut buf)
+        .expect("Fail to read to string");
+    let testcases: Vec<TestCase> = from_ron_string(&buf).expect("Fail to convert to testcases");
+    let cached_vm = rustpython_vm::Interpreter::with_init(Default::default(), |vm| {
+        vm.add_native_module("greptime", Box::new(greptime_builtin::make_module));
+        // this can be in `.enter()` closure, but for clearity, put it in the `with_init()`
+        PyVector::make_class(&vm.ctx);
+    });
+    for (idx, case) in testcases.into_iter().enumerate() {
+        print!("Testcase {idx} ...");
+        cached_vm
+        .enter(|vm| {
+            let scope = vm.new_scope_with_builtins();
+            case.input
+                .iter()
+                .try_for_each(|(k, v)| -> Result<(), String> {
+                    let v = PyValue::to_py_obj(&v.value, vm).unwrap();
+                    set_item_into_scope(&scope, vm, k, v)
+                })
+                .unwrap();
+            let code_obj = vm
+                .compile(
+                    &case.script,
+                    rustpython_vm::compile::Mode::BlockExpr,
+                    "<embedded>".to_owned(),
+                )
+                .map_err(|err| vm.new_syntax_error(&err))
+                .unwrap();
+            let res = vm.run_code_obj(code_obj, scope);
+            match res {
+                Err(e) => {
+                    let err_res = format_py_error(e, vm).to_string();
+                    match case.expect{
+                        Ok(v) => {
+                            println!("\nError:\n{err_res}");
+                            panic!("Expect Ok: {v:?}, found Error");
+                        },
+                        Err(err) => {
+                            if !err_res.contains(&err){
+                                panic!("Error message not containing, expect {err_res}, found {}", err)
+                            }
+                        }
+                    }
+                }
+                Ok(obj) => {
+                    let ser = PyValue::from_py_obj(&obj, vm);
+                    match (ser, case.expect){
+                        (Ok(real), Ok(expect)) => {
+                            if !(real.just_as_expect(&expect.value)){
+                                panic!("Not as Expected for code:\n{}\n Real Value is {real:#?}, but expect {expect:#?}", case.script)
+                            }
+                        },
+                        (Err(real), Err(expect)) => {
+                            if !expect.contains(&real){
+                                panic!("Expect Err(\"{expect}\"), found {real}")
+                            }
+                        },
+                        (Ok(real), Err(expect)) => panic!("Expect Err({expect}), found Ok({real:?})"),
+                        (Err(real), Ok(expect)) => panic!("Expect Ok({expect:?}), found Err({real})"),
+                    };
+                }
+            };
+        });
+        println!(" passed!");
+    }
+}
+
+fn set_item_into_scope(
+    scope: &Scope,
+    vm: &VirtualMachine,
+    name: &str,
+    value: impl ToPyObject,
+) -> Result<(), String> {
+    scope
+        .locals
+        .as_object()
+        .set_item(&name.to_owned(), vm.new_pyobj(value), vm)
+        .map_err(|err| {
+            format!(
+                "Error in setting var {name} in scope: \n{}",
+                format_py_error(err, vm)
+            )
+        })
+}
+
+fn set_lst_of_vecs_in_scope(
+    scope: &Scope,
+    vm: &VirtualMachine,
+    arg_names: &[&str],
+    args: Vec<PyVector>,
+) -> Result<(), String> {
+    let res = arg_names.iter().zip(args).try_for_each(|(name, vector)| {
+        scope
+            .locals
+            .as_object()
+            .set_item(name.to_owned(), vm.new_pyobj(vector), vm)
+            .map_err(|err| {
+                format!(
+                    "Error in setting var {name} in scope: \n{}",
+                    format_py_error(err, vm)
+                )
+            })
+    });
+    res
+}
+
+#[allow(unused_must_use)]
+#[test]
+fn test_vm() {
+    rustpython_vm::Interpreter::with_init(Default::default(), |vm| {
+        vm.add_native_module("udf_builtins", Box::new(greptime_builtin::make_module));
+        // this can be in `.enter()` closure, but for clearity, put it in the `with_init()`
+        PyVector::make_class(&vm.ctx);
+    })
+    .enter(|vm| {
+        let values = vec![1.0, 2.0, 3.0];
+        let pows = vec![0i8, -1i8, 3i8];
+
+        let args: Vec<VectorRef> = vec![
+            Arc::new(datatypes::vectors::Float32Vector::from_vec(values)),
+            Arc::new(datatypes::vectors::Int8Vector::from_vec(pows)),
+        ];
+        let args: Vec<PyVector> = args.into_iter().map(PyVector::from).collect();
+
+        let scope = vm.new_scope_with_builtins();
+        set_lst_of_vecs_in_scope(&scope, vm, &["values", "pows"], args).unwrap();
+        let code_obj = vm
+            .compile(
+                r#"
+from udf_builtins import *
+sin(values)"#,
+                rustpython_vm::compile::Mode::BlockExpr,
+                "<embedded>".to_owned(),
+            )
+            .map_err(|err| vm.new_syntax_error(&err))
+            .unwrap();
+        let res = vm.run_code_obj(code_obj, scope);
+        println!("{:#?}", res);
+        match res {
+            Err(e) => {
+                let err_res = format_py_error(e, vm).to_string();
+                println!("Error:\n{err_res}");
+            }
+            Ok(obj) => {
+                let _ser = PyValue::from_py_obj(&obj, vm);
+                dbg!(_ser);
+            }
+        }
+    });
+}

src/script/src/python/builtins/testcases.ron

@@ -1,6 +1,6 @@
 // This is the file for UDF&UDAF binding from datafusion, 
 // including most test for those function(except ApproxMedian which datafusion didn't implement)
-// check src/scalars/py_udf_module/test.rs for more information
+// check src/script/builtins/test.rs::run_builtin_fn_testcases() for more information
 [
     // math expressions
     TestCase(
@@ -670,7 +670,10 @@ pow(values, pows)"#,
         script: r#"
 from greptime import *
 pow(values, 1)"#,
-        expect: Err("TypeError: Can't cast operand of type `int` into `vector`.")
+        expect: Ok((
+            value: FloatVec([ 1.0, 2.0, 3.0]),
+            ty: Float64
+        ))
     ),
     TestCase(
         input: {
@@ -781,4 +784,145 @@ from greptime import *
 sin(num)"#,
         expect: Err("Can't cast object of type str into vector or scalar")
     ),
+    TestCase(
+        input: {},
+        script: r#"
+from greptime import *
+datetime("7d")"#,
+        expect: Ok((
+            ty: Int64,
+            value: Int(604800)
+        ))
+    ),
+    TestCase(
+        input: {},
+        script: r#"
+from greptime import *
+datetime("7dd")"#,
+        expect: Err("Unknown time unit")
+    ),
+    TestCase(
+        input: {},
+        script: r#"
+from greptime import *
+datetime("d7")"#,
+        expect: Err("Python Runtime error, error:")
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0])
+            ),
+            "ts": Var(
+                ty: Int64,
+                value: IntVec([0, 9, 20])
+            ),
+        },
+        script: r#"
+from greptime import *
+interval(ts, values, 10, lambda x:sum(x))"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVec([3.0, 3.0])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0, 4.0])
+            ),
+            "ts": Var(
+                ty: Int64,
+                value: IntVec([0, 9, 19, 20])
+            ),
+        },
+        script: r#"
+from greptime import *
+interval(ts, values, 10, lambda x:last(x))"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVec([2.0, 4.0])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0, 4.0])
+            ),
+            "ts": Var(
+                ty: Int64,
+                value: IntVec([0, 9, 19, 20])
+            ),
+        },
+        script: r#"
+from greptime import *
+interval(ts, values, 10, lambda x:first(x))"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVec([1.0, 3.0])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([])
+            )
+        },
+        script: r#"
+from greptime import *
+prev(values)"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVec([1.0])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0])
+            )
+        },
+        script: r#"
+from greptime import *
+prev(values)"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVecWithNull([None, Some(1.0), Some(2.0)])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0])
+            )
+        },
+        script: r#"
+from greptime import *
+next(values)"#,
+        expect: Ok((
+            ty: Float64,
+            value: FloatVecWithNull([Some(2.0), Some(3.0), None])
+        ))
+    ),
+    TestCase(
+        input: {
+            "values": Var(
+                ty: Float64,
+                value: FloatVec([1.0, 2.0, 3.0])
+            )
+        },
+        script: r#"
+from greptime import *
+sum(prev(values))"#,
+        expect: Ok((
+            ty: Float64,
+            value: Float(3.0)
+        ))
+    )
 ]

src/script/src/python/coprocessor.rs

@@ -7,7 +7,7 @@ use std::sync::Arc;
 use common_recordbatch::RecordBatch;
 use datafusion_common::record_batch::RecordBatch as DfRecordBatch;
 use datatypes::arrow;
-use datatypes::arrow::array::{Array, ArrayRef, BooleanArray, PrimitiveArray};
+use datatypes::arrow::array::{Array, ArrayRef};
 use datatypes::arrow::compute::cast::CastOptions;
 use datatypes::arrow::datatypes::{DataType, Field, Schema as ArrowSchema};
 use datatypes::schema::Schema;
@@ -22,8 +22,10 @@ use rustpython_parser::{
 };
 use rustpython_vm as vm;
 use rustpython_vm::{class::PyClassImpl, AsObject};
+#[cfg(test)]
+use serde::Deserialize;
 use snafu::{OptionExt, ResultExt};
-use vm::builtins::{PyBaseExceptionRef, PyBool, PyFloat, PyInt, PyTuple};
+use vm::builtins::{PyBaseExceptionRef, PyTuple};
 use vm::scope::Scope;
 use vm::{Interpreter, PyObjectRef, VirtualMachine};
 
@@ -31,19 +33,12 @@ use crate::fail_parse_error;
 use crate::python::builtins::greptime_builtin;
 use crate::python::coprocessor::parse::{ret_parse_error, DecoratorArgs};
 use crate::python::error::{
-    ensure, ArrowSnafu, CoprParseSnafu, OtherSnafu, PyCompileSnafu, PyParseSnafu, Result,
-    TypeCastSnafu,
+    ensure, ret_other_error_with, ArrowSnafu, CoprParseSnafu, OtherSnafu, PyCompileSnafu,
+    PyParseSnafu, Result, TypeCastSnafu,
 };
-use crate::python::utils::format_py_error;
+use crate::python::utils::{format_py_error, py_vec_obj_to_array};
 use crate::python::{utils::is_instance, PyVector};
 
-fn ret_other_error_with(reason: String) -> OtherSnafu<String> {
-    OtherSnafu { reason }
-}
-
-#[cfg(test)]
-use serde::Deserialize;
-
 #[cfg_attr(test, derive(Deserialize))]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct AnnotationInfo {
@@ -335,43 +330,9 @@ fn try_into_py_vector(fetch_args: Vec<ArrayRef>) -> Result<Vec<PyVector>> {
     Ok(args)
 }
 
-/// convert a single PyVector or a number(a constant) into a Array(or a constant array)
-fn py_vec_to_array_ref(obj: &PyObjectRef, vm: &VirtualMachine, col_len: usize) -> Result<ArrayRef> {
-    if is_instance::<PyVector>(obj, vm) {
-        let pyv = obj.payload::<PyVector>().with_context(|| {
-            ret_other_error_with(format!("can't cast obj {:?} to PyVector", obj))
-        })?;
-        Ok(pyv.to_arrow_array())
-    } else if is_instance::<PyInt>(obj, vm) {
-        let val = obj
-            .to_owned()
-            .try_into_value::<i64>(vm)
-            .map_err(|e| format_py_error(e, vm))?;
-
-        let ret = PrimitiveArray::from_vec(vec![val; col_len]);
-        Ok(Arc::new(ret) as _)
-    } else if is_instance::<PyFloat>(obj, vm) {
-        let val = obj
-            .to_owned()
-            .try_into_value::<f64>(vm)
-            .map_err(|e| format_py_error(e, vm))?;
-        let ret = PrimitiveArray::from_vec(vec![val; col_len]);
-        Ok(Arc::new(ret) as _)
-    } else if is_instance::<PyBool>(obj, vm) {
-        let val = obj
-            .to_owned()
-            .try_into_value::<bool>(vm)
-            .map_err(|e| format_py_error(e, vm))?;
-
-        let ret = BooleanArray::from_iter(std::iter::repeat(Some(val)).take(5));
-        Ok(Arc::new(ret) as _)
-    } else {
-        ret_other_error_with(format!("Expect a vector or a constant, found {:?}", obj)).fail()
-    }
-}
-
 /// convert a tuple of `PyVector` or one `PyVector`(wrapped in a Python Object Ref[`PyObjectRef`])
 /// to a `Vec<ArrayRef>`
+/// by default, a constant(int/float/bool) gives the a constant array of same length with input args
 fn try_into_columns(
     obj: &PyObjectRef,
     vm: &VirtualMachine,
@@ -383,11 +344,11 @@ fn try_into_columns(
         })?;
         let cols = tuple
             .iter()
-            .map(|obj| py_vec_to_array_ref(obj, vm, col_len))
+            .map(|obj| py_vec_obj_to_array(obj, vm, col_len))
             .collect::<Result<Vec<ArrayRef>>>()?;
         Ok(cols)
     } else {
-        let col = py_vec_to_array_ref(obj, vm, col_len)?;
+        let col = py_vec_obj_to_array(obj, vm, col_len)?;
         Ok(vec![col])
     }
 }

src/script/src/python/error.rs

@@ -9,6 +9,10 @@ pub use snafu::ensure;
 use snafu::{prelude::Snafu, Backtrace};
 pub type Result<T> = std::result::Result<T, Error>;
 
+pub(crate) fn ret_other_error_with(reason: String) -> OtherSnafu<String> {
+    OtherSnafu { reason }
+}
+
 #[derive(Debug, Snafu)]
 #[snafu(visibility(pub(crate)))]
 pub enum Error {

src/script/src/python/test.rs

@@ -198,10 +198,13 @@ fn test_calc_rvs() {
     "rv_180d"
 ])
 def calc_rvs(open_time, close):
-    from greptime import vector, log, prev, sqrt, datetime, pow, sum
+    from greptime import vector, log, prev, sqrt, datetime, pow, sum, last
+    import greptime as g
     def calc_rv(close, open_time, time, interval):
         mask = (open_time < time) & (open_time > time - interval)
         close = close[mask]
+        open_time = open_time[mask]
+        close = g.interval(open_time, close, datetime("10m"), lambda x:last(x))
 
         avg_time_interval = (open_time[-1] - open_time[0])/(len(open_time)-1)
         ref = log(close/prev(close))
@@ -211,12 +214,12 @@ def calc_rvs(open_time, close):
     # how to get env var,
     # maybe through accessing scope and serde then send to remote?
     timepoint = open_time[-1]
-    rv_7d = calc_rv(close, open_time, timepoint, datetime("7d"))
-    rv_15d = calc_rv(close, open_time, timepoint, datetime("15d"))
-    rv_30d = calc_rv(close, open_time, timepoint, datetime("30d"))
-    rv_60d = calc_rv(close, open_time, timepoint, datetime("60d"))
-    rv_90d = calc_rv(close, open_time, timepoint, datetime("90d"))
-    rv_180d = calc_rv(close, open_time, timepoint, datetime("180d"))
+    rv_7d = vector([calc_rv(close, open_time, timepoint, datetime("7d"))])
+    rv_15d = vector([calc_rv(close, open_time, timepoint, datetime("15d"))])
+    rv_30d = vector([calc_rv(close, open_time, timepoint, datetime("30d"))])
+    rv_60d = vector([calc_rv(close, open_time, timepoint, datetime("60d"))])
+    rv_90d = vector([calc_rv(close, open_time, timepoint, datetime("90d"))])
+    rv_180d = vector([calc_rv(close, open_time, timepoint, datetime("180d"))])
     return rv_7d, rv_15d, rv_30d, rv_60d, rv_90d, rv_180d
 "#;
     let close_array = PrimitiveArray::from_slice([
@@ -233,17 +236,8 @@ def calc_rvs(open_time, close):
         10120.43,
     ]);
     let open_time_array = PrimitiveArray::from_slice([
-        1581231300i64,
-        1581231360,
-        1581231420,
-        1581231480,
-        1581231540,
-        1581231600,
-        1581231660,
-        1581231720,
-        1581231780,
-        1581231840,
-        1581231900,
+        300i64, 900i64, 1200i64, 1800i64, 2400i64, 3000i64, 3600i64, 4200i64, 4800i64, 5400i64,
+        6000i64,
     ]);
     let schema = Arc::new(Schema::from(vec![
         Field::new("close", DataType::Float32, false),

src/script/src/python/testcases.ron

@@ -1,6 +1,6 @@
 // This is the file for python coprocessor's testcases, 
 // including coprocessor parsing test and execute test
-// check src/scalars/python/test.rs for more information
+// check src/script/python/test.rs::run_ron_testcases() for more information
 [
     (
         name: "correct_parse",

src/script/src/python/utils.rs

@@ -1,8 +1,15 @@
+use std::sync::Arc;
+
+use datafusion::arrow::array::{ArrayRef, BooleanArray, PrimitiveArray};
+use rustpython_vm::builtins::{PyBool, PyFloat, PyInt};
 use rustpython_vm::{builtins::PyBaseExceptionRef, PyObjectRef, PyPayload, PyRef, VirtualMachine};
+use snafu::OptionExt;
 use snafu::{Backtrace, GenerateImplicitData};
 
 use crate::python::error;
+use crate::python::error::ret_other_error_with;
 use crate::python::PyVector;
+
 pub(crate) type PyVectorRef = PyRef<PyVector>;
 
 /// use `rustpython`'s `is_instance` method to check if a PyObject is a instance of class.
@@ -25,3 +32,41 @@ pub fn format_py_error(excep: PyBaseExceptionRef, vm: &VirtualMachine) -> error:
         backtrace: Backtrace::generate(),
     }
 }
+
+/// convert a single PyVector or a number(a constant)(wrapping in PyObjectRef) into a Array(or a constant array)
+pub fn py_vec_obj_to_array(
+    obj: &PyObjectRef,
+    vm: &VirtualMachine,
+    col_len: usize,
+) -> Result<ArrayRef, error::Error> {
+    if is_instance::<PyVector>(obj, vm) {
+        let pyv = obj.payload::<PyVector>().with_context(|| {
+            ret_other_error_with(format!("can't cast obj {:?} to PyVector", obj))
+        })?;
+        Ok(pyv.to_arrow_array())
+    } else if is_instance::<PyInt>(obj, vm) {
+        let val = obj
+            .to_owned()
+            .try_into_value::<i64>(vm)
+            .map_err(|e| format_py_error(e, vm))?;
+        let ret = PrimitiveArray::from_vec(vec![val; col_len]);
+        Ok(Arc::new(ret) as _)
+    } else if is_instance::<PyFloat>(obj, vm) {
+        let val = obj
+            .to_owned()
+            .try_into_value::<f64>(vm)
+            .map_err(|e| format_py_error(e, vm))?;
+        let ret = PrimitiveArray::from_vec(vec![val; col_len]);
+        Ok(Arc::new(ret) as _)
+    } else if is_instance::<PyBool>(obj, vm) {
+        let val = obj
+            .to_owned()
+            .try_into_value::<bool>(vm)
+            .map_err(|e| format_py_error(e, vm))?;
+
+        let ret = BooleanArray::from_iter(std::iter::repeat(Some(val)).take(col_len));
+        Ok(Arc::new(ret) as _)
+    } else {
+        ret_other_error_with(format!("Expect a vector or a constant, found {:?}", obj)).fail()
+    }
+}