diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,5 @@ +# Revision history for prodapi-pg + +## 0.1.0.0 -- YYYY-mm-dd + +* First version. Released on an unsuspecting world. diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,202 @@ + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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As such, the Cabal (the library) +-- version used must be equal or greater than the version stated in this field. +-- Starting from the specification version 2.2, the cabal-version field must be +-- the first thing in the .cabal file. + +-- Initial package description 'prodapi-pg' generated by +-- 'cabal init'. For further documentation, see: +-- http://haskell.org/cabal/users-guide +-- +-- The name of the package. +name: prodapi-pg + +-- The package version. +-- See the Haskell package versioning policy (PVP) for standards +-- guiding when and how versions should be incremented. +-- https://pvp.haskell.org +-- PVP summary: +-+------- breaking API changes +-- | | +----- non-breaking API additions +-- | | | +--- code changes with no API change +version: 0.1.0.0 + +-- A short (one-line) description of the package. +-- synopsis: +synopsis: ProdAPI wrappers for postgresql-simple. + +-- A longer description of the package. +description: Provides ProdAPI-style tracing around postgresql-simple. + +-- The license under which the package is released. +license: Apache-2.0 + +-- The file containing the license text. +license-file: LICENSE + +-- The package author(s). +author: Lucas DiCioccio + +-- An email address to which users can send suggestions, bug reports, and patches. +maintainer: lucas@dicioccio.fr + +-- A copyright notice. +-- copyright: +category: Prod +build-type: Simple + +-- Extra doc files to be distributed with the package, such as a CHANGELOG or a README. +extra-doc-files: CHANGELOG.md + +-- Extra source files to be distributed with the package, such as examples, or a tutorial module. +-- extra-source-files: + +common warnings + ghc-options: -Wall + +library + -- Import common warning flags. + import: warnings + + -- Modules exported by the library. + exposed-modules: Prod.Pg.DatabaseUtils + Prod.Pg.TaskQueue + + -- Modules included in this library but not exported. + -- other-modules: + + -- LANGUAGE extensions used by modules in this package. + -- other-extensions: + + -- Other library packages from which modules are imported. + build-depends: base >=4.19.1.0 && <5, + prodapi-core >= 0.1.0 && < 0.2, + aeson >= 2.2.3.0 && < 2.3, + binary >= 0.8.9.3 && < 0.9, + bytestring >= 0.12.1.0 && < 0.13, + clock >=0.8.4 && < 0.9, + postgresql-simple >= 0.7.0.0 && < 0.8, + text >= 2.1.2 && < 2.2 + + -- Directories containing source files. + hs-source-dirs: src + + -- Base language which the package is written in. + default-language: Haskell2010 + +test-suite prodapi-pg-test + -- Import common warning flags. + import: warnings + + -- Base language which the package is written in. + default-language: Haskell2010 + + -- The interface type and version of the test suite. + type: exitcode-stdio-1.0 + + -- Directories containing source files. + hs-source-dirs: test + + -- The entrypoint to the test suite. + main-is: Main.hs + + -- Test dependencies. + build-depends: + base ^>=4.19.1.0, + prodapi-pg + diff --git a/src/Prod/Pg/DatabaseUtils.hs b/src/Prod/Pg/DatabaseUtils.hs new file mode 100644 --- /dev/null +++ b/src/Prod/Pg/DatabaseUtils.hs @@ -0,0 +1,113 @@ +{-# LANGUAGE OverloadedRecordDot #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE QuasiQuotes #-} +{-# LANGUAGE ScopedTypeVariables #-} + +module Prod.Pg.DatabaseUtils where + +import qualified Data.Binary.Builder as Builder +import qualified Data.ByteString as ByteString +import qualified Data.ByteString.Char8 as C8 +import Data.Int (Int64) +import Database.PostgreSQL.Simple (Connection, FromRow, Only (..), ToRow) +import qualified Database.PostgreSQL.Simple as Sql +import Database.PostgreSQL.Simple.SqlQQ (sql) +import Database.PostgreSQL.Simple.ToField (Action (..), ToField (..)) +import qualified Database.PostgreSQL.Simple.Types as Sql +import Prod.Tracer (Tracer (..), contramap) +import qualified System.Clock as Clock + +------------------------------------------------------------------------------- + +data PGConnectionTrace + = RunQuery ByteString.ByteString + | DoneQuery Clock.TimeSpec Clock.TimeSpec Int ByteString.ByteString + | RunExec Sql.Query + | DoneExec Clock.TimeSpec Clock.TimeSpec Int64 Sql.Query + +instance Show PGConnectionTrace where + show (RunQuery bs) = "`" <> C8.unpack bs <> "`" + show (DoneQuery t0 t1 k _) = mconcat ["n-rows=", show k, "; delay=", show (Clock.diffTimeSpec t1 t0)] + show (RunExec q) = "`" <> show q <> "`" + show (DoneExec t0 t1 k _) = mconcat ["result=", show k, "; delay=", show (Clock.diffTimeSpec t1 t0)] + +pgExec :: + (ToRow q) => + Tracer IO PGConnectionTrace -> + Connection -> + Sql.Query -> + q -> + IO Int64 +pgExec tracer conn q args = do + runTracer tracer (RunExec q) + t0 <- Clock.getTime Clock.Monotonic + ret <- Sql.execute conn q args + t1 <- Clock.getTime Clock.Monotonic + runTracer tracer (DoneExec t0 t1 ret q) + pure ret + +pgQuery :: + (ToRow q, FromRow r) => + Tracer IO PGConnectionTrace -> + Connection -> + Sql.Query -> + q -> + IO [r] +pgQuery tracer conn q args = do + formatted <- Sql.formatQuery conn q args + runTracer tracer (RunQuery formatted) + t0 <- Clock.getTime Clock.Monotonic + ret <- Sql.query conn q args + t1 <- Clock.getTime Clock.Monotonic + runTracer tracer (DoneQuery t0 t1 (length ret) formatted) + pure ret + +------------------------------------------------------------------------------- +data Trace + = RefreshMview MviewName ConcurrentlyOrNot PGConnectionTrace + | RefillMtable MtableFillingFunction PGConnectionTrace + deriving (Show) + +------------------------------------------------------------------------------- +newtype MviewName = MviewName ByteString.ByteString + deriving (Show) + +instance ToField MviewName where + toField (MviewName n) = Plain (Builder.fromByteString n) + +data ConcurrentlyOrNot + = Concurrently + | Blocking + deriving (Show, Eq) + +refreshMview :: + Tracer IO Trace -> + IO Connection -> + MviewName -> + ConcurrentlyOrNot -> + IO () +refreshMview tracer mkConn name c = do + conn <- mkConn + _ <- pgExec (contramap (RefreshMview name c) tracer) conn q (Only name) :: IO (Int64) + pure () + where + q = case c of + Blocking -> [sql|REFRESH MATERIALIZED VIEW ? |] + Concurrently -> [sql|REFRESH MATERIALIZED VIEW CONCURRENTLY ? |] + +------------------------------------------------------------------------------- +newtype MtableFillingFunction = MtableFillingFunction ByteString.ByteString + deriving (Show) + +execFillMTable :: + Tracer IO Trace -> + IO Connection -> + MtableFillingFunction -> + IO () +execFillMTable tracer mkConn selectfunc@(MtableFillingFunction sqlfun) = do + conn <- mkConn + _ <- pgQuery (contramap (RefillMtable selectfunc) tracer) conn q () :: IO [(Only ())] + pure () + where + q :: Sql.Query + q = Sql.Query ("select " <> sqlfun <> "()") diff --git a/src/Prod/Pg/TaskQueue.hs b/src/Prod/Pg/TaskQueue.hs new file mode 100644 --- /dev/null +++ b/src/Prod/Pg/TaskQueue.hs @@ -0,0 +1,186 @@ +{-# LANGUAGE OverloadedRecordDot #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE QuasiQuotes #-} +{-# LANGUAGE ScopedTypeVariables #-} + +-- todo: concurrency control with +-- \* monotonic version number and dead/alive checks +-- \* association to locks +module Prod.Pg.TaskQueue where + +import qualified Data.Aeson as Aeson +import Data.Foldable (for_) +import Data.Int (Int64) +import qualified Data.Maybe as Maybe +import qualified Data.Text as Text +import Data.Typeable (Typeable) +import Database.PostgreSQL.Simple (Connection, Only (..)) +import Database.PostgreSQL.Simple.Newtypes as SqlNewtypes +import Database.PostgreSQL.Simple.SqlQQ (sql) +import Prod.Stepper (Delayable (..), StepIO) +import qualified Prod.Stepper as Stepper +import Prod.Tracer (Tracer (..), contramap) + +------------------------------------------------------------------------------- +import Prod.Pg.DatabaseUtils (PGConnectionTrace, pgQuery) + +------------------------------------------------------------------------------- +type TaskId = Int64 + +data TaskHandle task + = TaskHandle + { taskId :: TaskId + , taskDefinition :: task + , markStarted :: Connection -> IO () + , markSuspended :: Connection -> IO () + , markFinished :: Connection -> IO () + } + +data PGTrace + = Enqueue PGConnectionTrace + | Enqueued TaskId + | NextTask PGConnectionTrace + | GotNextTask (Maybe TaskId) + | UpdateStatus Status TaskId PGConnectionTrace + | UpdatedTask Status (Maybe TaskId) + deriving (Show) + +enqueue :: + forall task. + (Aeson.ToJSON task) => + Tracer IO PGTrace -> + Connection -> + task -> + IO () +enqueue tracer conn task = do + let args = (Only $ SqlNewtypes.Aeson task) + xs :: [(Only TaskId)] <- pgQuery (contramap Enqueue tracer) conn q args + for_ xs $ \(Only x) -> + runTracer tracer (Enqueued x) + where + q = + [sql|INSERT INTO task_queue(status, priority, payload) + VALUES ('new', 50, ?) + RETURNING (id) |] + +nextTask :: + forall task. + (Typeable task, Aeson.FromJSON task) => + Tracer IO PGTrace -> + Connection -> + IO (Maybe (TaskHandle task)) +nextTask tracer conn = do + let args = (Only ("6 hours" :: Text.Text)) + xs :: [(TaskId, SqlNewtypes.Aeson task)] <- pgQuery (contramap NextTask tracer) conn q args + let xTask = Maybe.listToMaybe xs + runTracer tracer (GotNextTask $ fmap fst xTask) + return $ do + (tId, payload) <- xTask + pure $ + TaskHandle + tId + (SqlNewtypes.getAeson payload) + (updateTaskStatus tracer "started" tId) + (updateTaskStatus tracer "suspended" tId) + (updateTaskStatus tracer "finished" tId) + where + q = + [sql|WITH pick1 AS ( + SELECT id, payload + FROM task_queue + WHERE status IN ('new','suspended') + ORDER BY priority ASC, created_at DESC + LIMIT 1 + ), pick2 AS ( + SELECT id, payload + FROM task_queue + WHERE status IN ('started') AND age(updated_at) > ? + AND NOT (EXISTS (SELECT * FROM pick1)) + ORDER BY priority ASC, updated_at ASC + LIMIT 1 + ) + SELECT * FROM pick1 + UNION + SELECT * FROM pick2 + LIMIT 1|] + +type Status = Text.Text +type Priority = Text.Text + +updateTaskStatus :: + Tracer IO PGTrace -> + Status -> + TaskId -> + Connection -> + IO () +updateTaskStatus tracer st tId conn = do + let args = (st, priorityIncrement, tId) + xs :: [(Only Int64)] <- pgQuery (contramap (UpdateStatus st tId) tracer) conn q args + let xTask = Maybe.listToMaybe xs + runTracer tracer (UpdatedTask st (fmap fromOnly xTask)) + where + priorityIncrement :: Int64 + priorityIncrement = case st of "started" -> 20; "suspended" -> 100; _ -> 0 + q = + [sql|UPDATE task_queue + SET updated_at = NOW(), status = ?, priority = priority + ? + WHERE id = ? + RETURNING id|] + +------------------------------------------------------------------------------- + +data Step task + = LookupNextTask + | ClaimTask (TaskHandle task) + | WorkingOnTask (TaskHandle task) +instance Show (Step task) where + show LookupNextTask = "LookupNextTask" + show (ClaimTask t) = "ClaimTask { taskId = " <> show t.taskId <> " }" + show (WorkingOnTask t) = "WorkingOnTask { " <> show t.taskId <> " }" + +data Trace task + = StepperTrace (Stepper.Trace (Step task) ()) + | TraceSqlStatement Text.Text + | PrimitiveSql PGTrace + deriving (Show) + +data RunTaskResult + = Unstarted + | Final + +data RunTask = RunTask + +runTask :: + forall task. + (Typeable task, Aeson.FromJSON task, Aeson.ToJSON task) => + Tracer IO (Trace task) -> + IO Connection -> + (task -> Stepper.ExecFunctions RunTaskResult -> IO ()) -> + Stepper.BaseStepIO RunTask (Stepper.Delayable RunTaskResult) +runTask tracer mkConnection performTask = \complete _ -> do + lookupNextTask + (complete $ Inline Unstarted) + (claimTask (workOnTask complete)) + (Inline ()) + where + execution :: (a -> Step task) -> (Stepper.ExecFunctions b -> a -> IO ()) -> StepIO a b + execution f1 = + Stepper.defineExecution (contramap StepperTrace tracer) f1 (const ()) + + lookupNextTask :: IO () -> StepIO () (TaskHandle task) + lookupNextTask complete = execution (const LookupNextTask) $ \handle () -> do + t <- nextTask (contramap PrimitiveSql tracer) =<< mkConnection + case t of + Nothing -> print ("could not load task" :: String) >> complete + Just h -> handle.inline h + + claimTask :: StepIO (TaskHandle task) (TaskHandle task) + claimTask = execution ClaimTask $ \handle task -> do + task.markStarted =<< mkConnection + handle.inline task + + workOnTask :: StepIO (TaskHandle task) RunTaskResult + workOnTask = execution WorkingOnTask $ \handle task -> do + let f1 v = mkConnection >>= task.markFinished >> handle.inline v + let f2 delaySpec v = mkConnection >>= task.markSuspended >> handle.delay delaySpec v + performTask task.taskDefinition (Stepper.ExecFunctions f1 f2) diff --git a/test/Main.hs b/test/Main.hs new file mode 100644 --- /dev/null +++ b/test/Main.hs @@ -0,0 +1,4 @@ +module Main (main) where + +main :: IO () +main = putStrLn "Test suite not yet implemented."