feat: prometheus remote write and read (#346)

* feat: scaffold for prometheus protocol handler

* feat: impl remote write and read for prometheus

* chore: make label matchers working in remote reading

* chore: case senstive regexp matching for labers and tweak restful api

* test: prometheus test

* test: adds test for prometheus handler and http server

* fix: typo in comment

* refactor: move snappy_compress and snappy_decompress

* fix: by code review

* fix: collect_timeseries_ids

* fix: timestamp and value column's value may be null

src/api/build.rs

@@ -10,6 +10,7 @@ fn main() {
                 "greptime/v1/meta/heartbeat.proto",
                 "greptime/v1/meta/route.proto",
                 "greptime/v1/meta/store.proto",
+                "prometheus/remote/remote.proto",
             ],
             &["."],
         )

src/api/prometheus/remote/remote.proto

@@ -0,0 +1,85 @@
+// Copyright 2016 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package prometheus;
+
+option go_package = "prompb";
+
+import "prometheus/remote/types.proto";
+
+message WriteRequest {
+  repeated prometheus.TimeSeries timeseries = 1;
+  // Cortex uses this field to determine the source of the write request.
+  // We reserve it to avoid any compatibility issues.
+  reserved  2;
+  repeated prometheus.MetricMetadata metadata = 3;
+}
+
+// ReadRequest represents a remote read request.
+message ReadRequest {
+  repeated Query queries = 1;
+
+  enum ResponseType {
+    // Server will return a single ReadResponse message with matched series that includes list of raw samples.
+    // It's recommended to use streamed response types instead.
+    //
+    // Response headers:
+    // Content-Type: "application/x-protobuf"
+    // Content-Encoding: "snappy"
+    SAMPLES = 0;
+    // Server will stream a delimited ChunkedReadResponse message that contains XOR encoded chunks for a single series.
+    // Each message is following varint size and fixed size bigendian uint32 for CRC32 Castagnoli checksum.
+    //
+    // Response headers:
+    // Content-Type: "application/x-streamed-protobuf; proto=prometheus.ChunkedReadResponse"
+    // Content-Encoding: ""
+    STREAMED_XOR_CHUNKS = 1;
+  }
+
+  // accepted_response_types allows negotiating the content type of the response.
+  //
+  // Response types are taken from the list in the FIFO order. If no response type in `accepted_response_types` is
+  // implemented by server, error is returned.
+  // For request that do not contain `accepted_response_types` field the SAMPLES response type will be used.
+  repeated ResponseType accepted_response_types = 2;
+}
+
+// ReadResponse is a response when response_type equals SAMPLES.
+message ReadResponse {
+  // In same order as the request's queries.
+  repeated QueryResult results = 1;
+}
+
+message Query {
+  int64 start_timestamp_ms = 1;
+  int64 end_timestamp_ms = 2;
+  repeated prometheus.LabelMatcher matchers = 3;
+  prometheus.ReadHints hints = 4;
+}
+
+message QueryResult {
+  // Samples within a time series must be ordered by time.
+  repeated prometheus.TimeSeries timeseries = 1;
+}
+
+// ChunkedReadResponse is a response when response_type equals STREAMED_XOR_CHUNKS.
+// We strictly stream full series after series, optionally split by time. This means that a single frame can contain
+// partition of the single series, but once a new series is started to be streamed it means that no more chunks will
+// be sent for previous one. Series are returned sorted in the same way TSDB block are internally.
+message ChunkedReadResponse {
+  repeated prometheus.ChunkedSeries chunked_series = 1;
+
+  // query_index represents an index of the query from ReadRequest.queries these chunks relates to.
+  int64 query_index = 2;
+}

src/api/prometheus/remote/types.proto

@@ -0,0 +1,117 @@
+// Copyright 2017 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package prometheus;
+
+option go_package = "prompb";
+
+message MetricMetadata {
+  enum MetricType {
+    UNKNOWN        = 0;
+    COUNTER        = 1;
+    GAUGE          = 2;
+    HISTOGRAM      = 3;
+    GAUGEHISTOGRAM = 4;
+    SUMMARY        = 5;
+    INFO           = 6;
+    STATESET       = 7;
+  }
+
+  // Represents the metric type, these match the set from Prometheus.
+  // Refer to model/textparse/interface.go for details.
+  MetricType type = 1;
+  string metric_family_name = 2;
+  string help = 4;
+  string unit = 5;
+}
+
+message Sample {
+  double value    = 1;
+  // timestamp is in ms format, see model/timestamp/timestamp.go for
+  // conversion from time.Time to Prometheus timestamp.
+  int64 timestamp = 2;
+}
+
+message Exemplar {
+  // Optional, can be empty.
+  repeated Label labels = 1;
+  double value = 2;
+  // timestamp is in ms format, see model/timestamp/timestamp.go for
+  // conversion from time.Time to Prometheus timestamp.
+  int64 timestamp = 3;
+}
+
+// TimeSeries represents samples and labels for a single time series.
+message TimeSeries {
+  // For a timeseries to be valid, and for the samples and exemplars
+  // to be ingested by the remote system properly, the labels field is required.
+  repeated Label labels   = 1;
+  repeated Sample samples = 2;
+  repeated Exemplar exemplars = 3;
+}
+
+message Label {
+  string name  = 1;
+  string value = 2;
+}
+
+message Labels {
+  repeated Label labels = 1;
+}
+
+// Matcher specifies a rule, which can match or set of labels or not.
+message LabelMatcher {
+  enum Type {
+    EQ  = 0;
+    NEQ = 1;
+    RE  = 2;
+    NRE = 3;
+  }
+  Type type    = 1;
+  string name  = 2;
+  string value = 3;
+}
+
+message ReadHints {
+  int64 step_ms = 1;  // Query step size in milliseconds.
+  string func = 2;    // String representation of surrounding function or aggregation.
+  int64 start_ms = 3; // Start time in milliseconds.
+  int64 end_ms = 4;   // End time in milliseconds.
+  repeated string grouping = 5; // List of label names used in aggregation.
+  bool by = 6; // Indicate whether it is without or by.
+  int64 range_ms = 7; // Range vector selector range in milliseconds.
+}
+
+// Chunk represents a TSDB chunk.
+// Time range [min, max] is inclusive.
+message Chunk {
+  int64 min_time_ms = 1;
+  int64 max_time_ms = 2;
+
+  // We require this to match chunkenc.Encoding.
+  enum Encoding {
+    UNKNOWN = 0;
+    XOR     = 1;
+  }
+  Encoding type  = 3;
+  bytes data     = 4;
+}
+
+// ChunkedSeries represents single, encoded time series.
+message ChunkedSeries {
+  // Labels should be sorted.
+  repeated Label labels = 1;
+  // Chunks will be in start time order and may overlap.
+  repeated Chunk chunks = 2;
+}

src/api/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod error;
 pub mod helper;
+pub mod prometheus;
 pub mod serde;
 pub mod v1;
 

src/api/src/prometheus.rs

@@ -0,0 +1,5 @@
+#![allow(clippy::derive_partial_eq_without_eq)]
+
+pub mod remote {
+    tonic::include_proto!("prometheus");
+}