wip

todo: add s3 offloading progress, test epoch once its update will be fixed.

ref #115

Cargo.lock

@@ -2254,6 +2254,7 @@ dependencies = [
  "regex",
  "rust-s3",
  "serde",
+ "serde_json",
  "slog",
  "slog-async",
  "slog-scope",

pageserver/src/lib.rs

@@ -112,6 +112,9 @@ impl FromStr for ZTimelineId {
     fn from_str(s: &str) -> Result<ZTimelineId, Self::Err> {
         let timelineid = hex::decode(s)?;
 
+	if timelineid.len() != 16 {
+	    return Err(hex::FromHexError::InvalidStringLength);
+	}
         let mut buf: [u8; 16] = [0u8; 16];
         buf.copy_from_slice(timelineid.as_slice());
         Ok(ZTimelineId(buf))

test_runner/batch_others/test_wal_acceptor.py

@@ -1,6 +1,7 @@
 import pytest
 import random
 import time
+import json
 
 from contextlib import closing
 from multiprocessing import Process, Value
@@ -197,3 +198,22 @@ def test_race_conditions(zenith_cli, pageserver, postgres, wa_factory, stop_valu
 
     stop_value.value = 1
     proc.join()
+
+def test_state(zenith_cli, pageserver, postgres, wa_factory):
+    wa_factory.start_n_new(1)
+
+    zenith_cli.run(["branch", "test_wal_acceptors_state", "empty"])
+    pg = postgres.create_start('test_wal_acceptors_state',
+                               wal_acceptors=wa_factory.get_connstrs())
+
+    # learn zenith timeline from compute
+    ztli = pg.safe_psql("show zenith.zenith_timeline")[0][0]
+
+    pg.safe_psql("create table t(i int)")
+
+    pg.stop().start()
+    pg.safe_psql("insert into t values(10)")
+
+    wa = wa_factory.instances[0]
+    state = wa.safe_psql("state", options="'-c ztimelineid={}'".format(ztli), sslmode='disable')[0][0]
+    print(state)

test_runner/fixtures/zenith_fixtures.py

@@ -85,13 +85,17 @@ class PgProtocol:
         self.port = port
         self.username = username or getpass.getuser()
 
-    def connstr(self, *, dbname: str = 'postgres', username: Optional[str] = None) -> str:
+    def connstr(self, *, dbname: str = 'postgres', username: Optional[str] = None, **kwargs) -> str:
         """
         Build a libpq connection string for the Postgres instance.
         """
 
         username = username or self.username
-        return f'host={self.host} port={self.port} user={username} dbname={dbname}'
+        connstr = f'host={self.host} port={self.port} user={username} dbname={dbname}'
+        for k, v in kwargs.items():
+            connstr += " {}={}".format(k, v)
+        print("connstr is {}".format(connstr))
+        return connstr
 
     # autocommit=True here by default because that's what we need most of the time
     def connect(self, *, autocommit=True, **kwargs: Any) -> PgConnection:
@@ -458,9 +462,10 @@ def read_pid(path):
     return int(Path(path).read_text())
 
 
-class WalAcceptor:
+class WalAcceptor(PgProtocol):
     """ An object representing a running wal acceptor daemon. """
     def __init__(self, wa_binpath, data_dir, port, num):
+        super().__init__(host='127.0.0.1', port=port)
         self.wa_binpath = wa_binpath
         self.data_dir = data_dir
         self.port = port

walkeeper/Cargo.toml

@@ -30,6 +30,7 @@ crc32c = "0.6.0"
 parse_duration = "2.1.1"
 walkdir = "2"
 serde = { version = "1.0", features = ["derive"] }
+serde_json = "1"
 hex = "0.4.3"
 
 # FIXME: 'pageserver' is needed for ZTimelineId. Refactor

walkeeper/src/receive_wal.rs

@@ -213,8 +213,8 @@ impl ReceiveWalConn {
             self.peer_addr, server_info.system_id, server_info.timeline_id,
         );
         // FIXME: also check that the system identifier matches
-        self.timeline.set(server_info.timeline_id)?;
-        self.timeline.get().load_control_file(&self.conf)?;
+        self.timeline
+            .set(&self.conf, server_info.timeline_id, true)?;
 
         let mut my_info = self.timeline.get().get_info();
 

walkeeper/src/send_wal.rs

@@ -1,5 +1,5 @@
 //! Part of WAL acceptor pretending to be Postgres, streaming xlog to
-//! pageserver/any other consumer.
+//! pageserver/any other consumer and answering to some utility queries.
 //!
 
 use crate::replication::ReplicationConn;
@@ -12,7 +12,7 @@ use std::str::FromStr;
 use std::sync::Arc;
 use zenith_utils::postgres_backend;
 use zenith_utils::postgres_backend::PostgresBackend;
-use zenith_utils::pq_proto::{BeMessage, FeStartupMessage, RowDescriptor};
+use zenith_utils::pq_proto::{BeMessage, FeStartupMessage, RowDescriptor, JSON_OID, TEXT_OID};
 
 /// Handler for streaming WAL from acceptor
 pub struct SendWalHandler {
@@ -26,10 +26,14 @@ pub struct SendWalHandler {
 impl postgres_backend::Handler for SendWalHandler {
     fn startup(&mut self, _pgb: &mut PostgresBackend, sm: &FeStartupMessage) -> Result<()> {
         match sm.params.get("ztimelineid") {
-            Some(ref ztimelineid) => {
-                let ztlid = ZTimelineId::from_str(ztimelineid)?;
-                self.timeline.set(ztlid)?;
-            }
+            Some(ref ztimelineid) => match ZTimelineId::from_str(ztimelineid) {
+                Ok(ztlid) => {
+                    self.timeline.set(&self.conf, ztlid, false)?;
+                }
+                Err(e) => {
+                    bail!("failed to parse ztimelineid: {}", e)
+                }
+            },
             _ => bail!("timelineid is required"),
         }
         if let Some(app_name) = sm.params.get("application_name") {
@@ -41,13 +45,18 @@ impl postgres_backend::Handler for SendWalHandler {
     fn process_query(&mut self, pgb: &mut PostgresBackend, query_string: Bytes) -> Result<()> {
         if query_string.starts_with(b"IDENTIFY_SYSTEM") {
             self.handle_identify_system(pgb)?;
-            Ok(())
         } else if query_string.starts_with(b"START_REPLICATION") {
             ReplicationConn::new(pgb).run(self, pgb, &query_string)?;
-            Ok(())
+        } else if query_string.starts_with(b"state") {
+            self.handle_state(pgb)?;
+        } else if query_string.to_ascii_lowercase().starts_with(b"set ") {
+            // have it because psycopg2 executes "SET datestyle TO 'ISO'"
+            // on connect
+            pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else {
             bail!("Unexpected command {:?}", query_string);
         }
+        Ok(())
     }
 }
 
@@ -75,7 +84,7 @@ impl SendWalHandler {
         pgb.write_message_noflush(&BeMessage::RowDescription(&[
             RowDescriptor {
                 name: b"systemid",
-                typoid: 25,
+                typoid: TEXT_OID,
                 typlen: -1,
                 ..Default::default()
             },
@@ -87,13 +96,13 @@ impl SendWalHandler {
             },
             RowDescriptor {
                 name: b"xlogpos",
-                typoid: 25,
+                typoid: TEXT_OID,
                 typlen: -1,
                 ..Default::default()
             },
             RowDescriptor {
                 name: b"dbname",
-                typoid: 25,
+                typoid: TEXT_OID,
                 typlen: -1,
                 ..Default::default()
             },
@@ -107,4 +116,21 @@ impl SendWalHandler {
         .write_message(&BeMessage::CommandComplete(b"IDENTIFY_SYSTEM"))?;
         Ok(())
     }
+
+    /// Send current state of safekeeper
+    fn handle_state(&mut self, pgb: &mut PostgresBackend) -> Result<()> {
+        let my_info = self.timeline.get().get_info();
+        pgb.write_message_noflush(&BeMessage::RowDescription(&[RowDescriptor {
+            name: b"state",
+            typoid: JSON_OID,
+            typlen: -1,
+            ..Default::default()
+        }]))?
+        .write_message_noflush(&BeMessage::DataRow(&[Some(
+            serde_json::to_string(&my_info).unwrap().as_bytes(),
+        )]))?
+        .write_message(&BeMessage::CommandComplete(b"IDENTIFY_SYSTEM"))?;
+
+        Ok(())
+    }
 }

walkeeper/src/timeline.rs

@@ -55,10 +55,12 @@ impl SharedState {
     }
 
     /// Load and lock control file (prevent running more than one instance of safekeeper)
+    /// If create=false and file doesn't exist, bails out.
     pub fn load_control_file(
         &mut self,
         conf: &WalAcceptorConf,
         timelineid: ZTimelineId,
+        create: bool,
     ) -> Result<()> {
         if self.control_file.is_some() {
             info!("control file for timeline {} is already open", timelineid);
@@ -69,13 +71,17 @@ impl SharedState {
             .data_dir
             .join(timelineid.to_string())
             .join(CONTROL_FILE_NAME);
-        info!("loading control file {}", control_file_path.display());
-        match OpenOptions::new()
-            .read(true)
-            .write(true)
-            .create(true)
-            .open(&control_file_path)
-        {
+        info!(
+            "loading control file {}, create={}",
+            control_file_path.display(),
+            create
+        );
+        let mut opts = OpenOptions::new();
+        opts.read(true).write(true);
+        if create {
+            opts.create(true);
+        }
+        match opts.open(&control_file_path) {
             Ok(file) => {
                 // Lock file to prevent two or more active wal_acceptors
                 match file.try_lock_exclusive() {
@@ -91,29 +97,36 @@ impl SharedState {
                 self.control_file = Some(file);
 
                 let cfile_ref = self.control_file.as_mut().unwrap();
-                match SafeKeeperInfo::des_from(cfile_ref) {
-                    Err(e) => {
-                        warn!("read from {:?} failed: {}", control_file_path, e);
+                if cfile_ref.metadata().unwrap().len() == 0 {
+                    if !create {
+                        bail!("control file is empty");
                     }
-                    Ok(info) => {
-                        if info.magic != SK_MAGIC {
-                            bail!("Invalid control file magic: {}", info.magic);
+                } else {
+                    match SafeKeeperInfo::des_from(cfile_ref) {
+                        Err(e) => {
+                            bail!("failed to read control file {:?}: {}", control_file_path, e);
                         }
-                        if info.format_version != SK_FORMAT_VERSION {
-                            bail!(
-                                "Incompatible format version: {} vs. {}",
-                                info.format_version,
-                                SK_FORMAT_VERSION
-                            );
+                        Ok(info) => {
+                            if info.magic != SK_MAGIC {
+                                bail!("Invalid control file magic: {}", info.magic);
+                            }
+                            if info.format_version != SK_FORMAT_VERSION {
+                                bail!(
+                                    "Incompatible format version: {} vs. {}",
+                                    info.format_version,
+                                    SK_FORMAT_VERSION
+                                );
+                            }
+                            self.info = info;
                         }
-                        self.info = info;
                     }
                 }
             }
             Err(e) => {
-                panic!(
+                bail!(
                     "Failed to open control file {:?}: {}",
-                    &control_file_path, e
+                    &control_file_path,
+                    e
                 );
             }
         }
@@ -198,9 +211,9 @@ impl Timeline {
         shared_state.hs_feedback.clone()
     }
 
-    pub fn load_control_file(&self, conf: &WalAcceptorConf) -> Result<()> {
+    pub fn load_control_file(&self, conf: &WalAcceptorConf, create: bool) -> Result<()> {
         let mut shared_state = self.mutex.lock().unwrap();
-        shared_state.load_control_file(conf, self.timelineid)
+        shared_state.load_control_file(conf, self.timelineid, create)
     }
 
     pub fn save_control_file(&self, sync: bool) -> Result<()> {
@@ -211,17 +224,23 @@ impl Timeline {
 
 // Utilities needed by various Connection-like objects
 pub trait TimelineTools {
-    fn set(&mut self, timeline_id: ZTimelineId) -> Result<()>;
+    fn set(&mut self, conf: &WalAcceptorConf, timeline_id: ZTimelineId, create: bool)
+        -> Result<()>;
     fn get(&self) -> &Arc<Timeline>;
     fn find_end_of_wal(&self, data_dir: &Path, precise: bool) -> (Lsn, TimeLineID);
 }
 
 impl TimelineTools for Option<Arc<Timeline>> {
-    fn set(&mut self, timeline_id: ZTimelineId) -> Result<()> {
+    fn set(
+        &mut self,
+        conf: &WalAcceptorConf,
+        timeline_id: ZTimelineId,
+        create: bool,
+    ) -> Result<()> {
         // We will only set the timeline once. If it were to ever change,
         // anyone who cloned the Arc would be out of date.
         assert!(self.is_none());
-        *self = Some(GlobalTimelines::store(timeline_id)?);
+        *self = Some(GlobalTimelines::get(conf, timeline_id, create)?);
         Ok(())
     }
 
@@ -243,11 +262,16 @@ lazy_static! {
 }
 
 /// A zero-sized struct used to manage access to the global timelines map.
-struct GlobalTimelines;
+pub struct GlobalTimelines;
 
 impl GlobalTimelines {
-    /// Store a new timeline into the global TIMELINES map.
-    fn store(timeline_id: ZTimelineId) -> Result<Arc<Timeline>> {
+    /// Get a timeline with control file loaded from the global TIMELINES map.
+    /// If control file doesn't exist and create=false, bails out.
+    pub fn get(
+        conf: &WalAcceptorConf,
+        timeline_id: ZTimelineId,
+        create: bool,
+    ) -> Result<Arc<Timeline>> {
         let mut timelines = TIMELINES.lock().unwrap();
 
         match timelines.get(&timeline_id) {
@@ -258,9 +282,10 @@ impl GlobalTimelines {
 
                 let shared_state = SharedState::new();
 
-                let new_tid = Arc::new(Timeline::new(timeline_id, shared_state));
-                timelines.insert(timeline_id, Arc::clone(&new_tid));
-                Ok(new_tid)
+                let new_tli = Arc::new(Timeline::new(timeline_id, shared_state));
+                new_tli.load_control_file(conf, create)?;
+                timelines.insert(timeline_id, Arc::clone(&new_tli));
+                Ok(new_tli)
             }
         }
     }

zenith_utils/src/postgres_backend.rs

@@ -116,7 +116,12 @@ impl PostgresBackend {
                 Some(FeMessage::StartupMessage(m)) => {
                     trace!("got startup message {:?}", m);
 
-                    handler.startup(self, &m)?;
+                    if let Err(e) = handler.startup(self, &m) {
+                        // try to send error to the client
+                        let errmsg = format!("{}", e);
+                        self.write_message(&BeMessage::ErrorResponse(errmsg))?;
+                        return Err(e);
+                    }
 
                     match m.kind {
                         StartupRequestCode::NegotiateGss | StartupRequestCode::NegotiateSsl => {

zenith_utils/src/pq_proto.rs

@@ -366,6 +366,7 @@ pub struct XLogDataBody<'a> {
 
 pub static HELLO_WORLD_ROW: BeMessage = BeMessage::DataRow(&[Some(b"hello world")]);
 pub const TEXT_OID: Oid = 25;
+pub const JSON_OID: Oid = 114;
 // single text column
 pub static SINGLE_COL_ROWDESC: BeMessage = BeMessage::RowDescription(&[RowDescriptor {
     name: b"data",