diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/distributed-fork-aws-lambda.cabal b/distributed-fork-aws-lambda.cabal new file mode 100644 --- /dev/null +++ b/distributed-fork-aws-lambda.cabal @@ -0,0 +1,65 @@ +name: distributed-fork-aws-lambda +version: 0.0.1.0 +synopsis: AWS Lambda backend for distributed-fork. +homepage: https://github.com/utdemir/distributed-fork +license: BSD3 +license-file: LICENSE +author: Utku Demir +maintainer: me@utdemir.com +copyright: Utku Demir +category: Web +build-type: Simple +cabal-version: >=1.10 + +description: + backend for . + +library + hs-source-dirs: src + default-language: Haskell2010 + exposed-modules: Control.Distributed.Fork.Lambda + other-modules: Control.Distributed.Fork.Lambda.Internal.Types + , Control.Distributed.Fork.Lambda.Internal.Constants + , Control.Distributed.Fork.Lambda.Internal.Stack + , Control.Distributed.Fork.Lambda.Internal.Archive + , Control.Distributed.Fork.Lambda.Internal.Invoke + , Control.Concurrent.Throttled + ghc-options: -Wall + build-depends: base >= 4.7 && < 5 + , distributed-fork + , SHA + , aeson + , aeson-qq + , amazonka + , amazonka-cloudformation + , amazonka-core + , amazonka-lambda >= 1.6.0 + , amazonka-s3 + , amazonka-sqs + , async + , base64-bytestring + , bytestring + , containers + , interpolate + , lens + , lens-aeson + , safe-exceptions + , stratosphere >= 0.15.0 + , text + , time + , typed-process + , unordered-containers + , zip-archive + +test-suite tests + type: exitcode-stdio-1.0 + hs-source-dirs: test + main-is: Test.hs + default-language: Haskell2010 + ghc-options: -Wall -static -optl-static -optl-pthread -fPIC + build-depends: base >=4.7 && < 5 + , distributed-fork + , distributed-fork-aws-lambda + , tasty + , tasty-hunit + , text diff --git a/src/Control/Concurrent/Throttled.hs b/src/Control/Concurrent/Throttled.hs new file mode 100644 --- /dev/null +++ b/src/Control/Concurrent/Throttled.hs @@ -0,0 +1,30 @@ +module Control.Concurrent.Throttled + ( Throttle + , newThrottle + , throttled + ) where + +-------------------------------------------------------------------------------- +import Control.Monad +import Control.Exception +import Control.Concurrent +-------------------------------------------------------------------------------- + +newtype Throttle + = Throttle (MVar (MVar ())) + +newThrottle :: Int -> IO Throttle +newThrottle maxConcurrent = do + mv <- newEmptyMVar + forM_ [1..maxConcurrent] $ \_ -> forkIO . forever $ do + m <- takeMVar mv + putMVar m () + putMVar m () + return $ Throttle mv + +throttled :: Throttle -> IO a -> IO a +throttled (Throttle mv) act = do + m <- newEmptyMVar + putMVar mv m + readMVar m + act `finally` takeMVar m diff --git a/src/Control/Distributed/Fork/Lambda.hs b/src/Control/Distributed/Fork/Lambda.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda.hs @@ -0,0 +1,167 @@ +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE RecordWildCards #-} + +-- | +-- Provides a 'Backend' using AWS Lambda functions. +-- +-- In order to do that, roughly: +-- +-- * It creates a deployment archive containing the program binary and +-- a tiny wrapper written in Python and uploads it to the given S3 bucket. +-- * Creates a CloudFormation stack containing the Lambda function and +-- an SQS queue to gather the answers. +-- * It starts polling the SQS queue for any answers. +-- * When executing, it invokes the Lambda function using asynchronous +-- invocation mode and blocks until a message appears in the queue. +-- * On exit, it deletes the CloudFormation stack. +-- +-- Some warts: +-- +-- * The same binary should run on AWS Lambda. In practice, this means: +-- +-- * You have to build and use this library on a Linux machine. +-- +-- * You have to statically link everything. You can use GHC's +-- '@-static -optl-static -optl-pthread -fPIC@' parameters for that. +-- See +-- for an example. +-- +-- * On AWS Lambda, more memory you assign to a function, more CPU you +-- get. So it might make your function run faster if you overallocate +-- memory. +-- * When invoked asynchronously, AWS Lambda retries the invocation +-- 2 more times waiting a minute between every retry. This means when +-- something fails, it will take at least a few minutes to until you +-- get an exception. + +module Control.Distributed.Fork.Lambda + ( + -- * Usage + withLambdaBackend + -- * Options + , LambdaBackendOptions + , lambdaBackendOptions + , lboPrefix + , lboMemory + ) where + +import Data.Bool (bool) +import Data.Monoid ((<>)) +import qualified Data.Text as T +import Data.Time.Clock (getCurrentTime) +import Data.Time.Format (defaultTimeLocale, + formatTime) +import Control.Lens ((^.), Lens', lens) +import Network.AWS (Credentials (Discover), + envRegion, + newEnv, + runAWS, + runResourceT) +-------------------------------------------------------------------------------- +import Control.Distributed.Fork.Backend +import Control.Distributed.Fork.Lambda.Internal.Archive +import Control.Distributed.Fork.Lambda.Internal.Invoke +import Control.Distributed.Fork.Lambda.Internal.Stack +import Control.Distributed.Fork.Lambda.Internal.Types +-------------------------------------------------------------------------------- + +-- | +-- Provides a 'Backend' using AWS Lambda functions. +-- +-- Created AWS resources except the uploaded deployment package will be cleaned +-- up when exiting. +-- +-- Example usage: +-- +-- @ +-- {-\# LANGUAGE StaticPointers #-} +-- +-- import Control.Lens +-- import Control.Distributed.Fork +-- import Control.Distributed.Fork.Lambda +-- +-- opts :: LambdaBackendOptions +-- opts = lambdaBackendOptions "my-s3-bucket" +-- & lboMemory .~ 1024 +-- +-- main :: IO () +-- main = do +-- 'initServerless' +-- 'withLambdaBackend' opts $ \backend -> do +-- ret <- 'execute' 'backend' (static 'Dict') (static (return "Hello from Lambda!")) +-- putStrLn ret +-- @ + +withLambdaBackend :: LambdaBackendOptions -> (Backend -> IO a) -> IO a +withLambdaBackend LambdaBackendOptions {..} f = do + env <- newEnv Discover + putStrLn $ "Detected region: " <> show (env ^. envRegion) <> "." + + archive <- mkArchive + let cksum = archiveChecksum archive + size = fromIntegral (archiveSize archive) / (1000 * 1000) :: Double + s3loc = + S3Loc (BucketName _lboBucket) (_lboPrefix <> "-" <> cksum <> ".zip") + + putStrLn "Checking if deployment archive exists." + runResourceT . runAWS env $ + awsObjectExists s3loc >>= + bool + (liftIO (putStrLn $ "Uploading the deployment archive. (" <> show size <> " MB)") + >> awsUploadObject s3loc (archiveToByteString archive)) + (liftIO $ putStrLn "Found archive, skipping upload.") + + + time <- + T.pack . formatTime defaultTimeLocale "%Y%m%d%H%M%S" <$> getCurrentTime + let stackOptions = + StackOptions { soName = StackName (_lboPrefix <> "-" <> time <> "-" <> cksum) + , soLambdaMemory = _lboMemory + , soLambdaCode = s3loc + } + + putStrLn "Creating stack." + withStack stackOptions env $ \si -> do + putStrLn "Stack created." + putStrLn $ "Artifact: " <> show s3loc + putStrLn $ "Stack Id: " <> T.unpack (siId si) + withInvoke env si $ \invoke -> + f $ Backend invoke + +-------------------------------------------------------------------------------- + +-- | +-- Options required for creating a Lambda backend. +-- +-- Use 'lambdaBackendOptions' smart constructor to create and lenses below for +-- setting optional fields. +data LambdaBackendOptions = LambdaBackendOptions + { _lboBucket :: T.Text + , _lboPrefix :: T.Text + , _lboMemory :: Int + } + +lambdaBackendOptions :: T.Text -- ^ Name of the S3 bucket to store the deployment archive in. + -> LambdaBackendOptions +lambdaBackendOptions bucket = + LambdaBackendOptions { _lboBucket = bucket + , _lboPrefix = "distributed-fork" + , _lboMemory = 128 + } + +-- | +-- Desired memory for the Lambda functions. +-- +-- See for allowed values. +-- +-- Default: 128 +lboMemory :: Lens' LambdaBackendOptions Int +lboMemory = lens _lboMemory (\s t -> s { _lboMemory = t }) + +-- | +-- Prefix to the deployment archive and the CloudFormation stack. +-- +-- Default: "distributed-fork" +lboPrefix :: Lens' LambdaBackendOptions T.Text +lboPrefix = lens _lboPrefix (\s t -> s { _lboPrefix = t }) + diff --git a/src/Control/Distributed/Fork/Lambda/Internal/Archive.hs b/src/Control/Distributed/Fork/Lambda/Internal/Archive.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda/Internal/Archive.hs @@ -0,0 +1,129 @@ +{-# LANGUAGE BinaryLiterals #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE QuasiQuotes #-} + +{- +This module contains the executables for the Lambda function. +-} + +module Control.Distributed.Fork.Lambda.Internal.Archive + ( Archive (..) + , mkArchive + , archiveSize + , archiveChecksum + ) where + +-------------------------------------------------------------------------------- +import Codec.Archive.Zip hiding + (Archive) +import Control.Exception +import Control.Monad +import qualified Data.ByteString as BS +import qualified Data.ByteString.Lazy as BL +import Data.Digest.Pure.SHA +import Data.Function +import Data.String.Interpolate +import qualified Data.Text as T +import qualified Data.Text.Encoding as T +import System.Process.Typed +-------------------------------------------------------------------------------- +import Control.Distributed.Fork.Backend +import Control.Distributed.Fork.Lambda.Internal.Constants +-------------------------------------------------------------------------------- + +{- +Since AWS Lambda does not support binary execution by default, our entry point +is a small Python script, whose only purpose is to execute the attached Haskell +binary, provide the input from standard input and return the standard output to +the queue. +-} +handlerPy :: BS.ByteString +handlerPy = T.encodeUtf8 $ T.pack [i| +import os +import subprocess +from base64 import * +import boto3 + +queue_url = os.environ["#{envAnswerQueueUrl}"] +client = boto3.client('sqs') + +def handle(event, context): + popen = subprocess.Popen( + ["./#{hsMainName}", "#{argExecutorMode}"], + stdin=subprocess.PIPE, stdout=subprocess.PIPE) + (out, _) = popen.communicate(b64decode(event["d"])) + client.send_message( + QueueUrl=queue_url, + MessageBody=b64encode(out), + MessageAttributes={ + "Id": { + "DataType": "Number", + "StringValue": str(event["i"]) + } + } + ) + +|] + +{- +And we read the current executable. + +Since it'll run on AWS Lambda, it needs to be a statically linked Linux +executable, so we do a preliminary check here. We're calling the "file" +command here instead of using libmagic, because trying to statically compile +it caused problems on my system. +-} +mkHsMain :: IO BS.ByteString +mkHsMain = do + path <- getExecutablePath + checkFile path + BS.readFile path + where + checkFile path = do + ret <- + liftIO $ + T.splitOn ", " . T.decodeUtf8 . BL.toStrict <$> + readProcessStdout_ (proc "file" ["--brief", path]) + let preds :: [(T.Text, T.Text)] + preds = + [ ( "ELF 64-bit LSB executable" + , "file is not an 64 bit ELF executable") + , ( "statically linked" + , "file is not statically linked" + ) + ] + forM_ preds $ \(str, ex) -> + if str `elem` ret + then return () + else throwIO (FileException ex) + return () + +newtype FileException + = FileException T.Text + deriving Show + +instance Exception FileException + +{- +And we're going to put all of them in a zip archive. +-} +newtype Archive = + Archive { archiveToByteString :: BS.ByteString } + +mkArchive :: IO Archive +mkArchive = do + hsMain <- mkHsMain + return . Archive . BL.toStrict . fromArchive $ + emptyArchive + & addEntryToArchive + (toEntry handlerPyName 0 $ BL.fromStrict handlerPy) + & addEntryToArchive + (toEntry hsMainName 0 $ BL.fromStrict hsMain) + { eExternalFileAttributes = 0b10000 {- rwx -} } + +archiveSize :: Archive -> Integer +archiveSize = fromIntegral . BS.length . archiveToByteString + +archiveChecksum :: Archive -> T.Text +archiveChecksum = + T.pack . showDigest . sha1 . BL.fromStrict . archiveToByteString diff --git a/src/Control/Distributed/Fork/Lambda/Internal/Constants.hs b/src/Control/Distributed/Fork/Lambda/Internal/Constants.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda/Internal/Constants.hs @@ -0,0 +1,16 @@ +{-# LANGUAGE OverloadedStrings #-} + +module Control.Distributed.Fork.Lambda.Internal.Constants where + +-------------------------------------------------------------------------------- +import Data.Text (Text) +-------------------------------------------------------------------------------- + +hsMainName :: String +hsMainName = "hs-main" + +handlerPyName :: String +handlerPyName = "handler.py" + +envAnswerQueueUrl :: Text +envAnswerQueueUrl = "ANSWER_QUEUE_URL" diff --git a/src/Control/Distributed/Fork/Lambda/Internal/Invoke.hs b/src/Control/Distributed/Fork/Lambda/Internal/Invoke.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda/Internal/Invoke.hs @@ -0,0 +1,196 @@ +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE RecordWildCards #-} +{-# LANGUAGE TypeApplications #-} + +module Control.Distributed.Fork.Lambda.Internal.Invoke + ( withInvoke + ) where + +-------------------------------------------------------------------------------- +import Control.Concurrent.Async +import Control.Concurrent.MVar +import Control.Exception.Safe +import Control.Lens +import Control.Monad +import qualified Data.Aeson as A +import Data.Aeson.Lens +import qualified Data.ByteString as BS +import qualified Data.ByteString.Lazy as BL +import Data.ByteString.Base64 as B64 +import qualified Data.HashMap.Strict as HM +import qualified Data.Map.Strict as M +import Data.Maybe +import Data.Monoid +import qualified Data.Text as T +import qualified Data.Text.Encoding as T +import Network.AWS +import Network.AWS.Lambda +import Network.AWS.SQS +import Text.Read +-------------------------------------------------------------------------------- +import Control.Concurrent.Throttled +import Control.Distributed.Fork.Backend +import Control.Distributed.Fork.Lambda.Internal.Stack (StackInfo (..)) +-------------------------------------------------------------------------------- + +{- +Since we're going to get our answers asynchronously, we maintain a state with +callbacks for individual invocations. + +Every individual invocation have an incrementing id, so we can distinguish +the responses. +-} +data LambdaState = LambdaState + { lsInvocations :: M.Map Int (IO BS.ByteString -> IO ()) + , lsNextId :: Int + } + +data LambdaEnv = LambdaEnv + { leState :: MVar LambdaState + , leStack :: StackInfo + , leEnv :: Env + } + +newLambdaEnv :: Env -> StackInfo -> IO LambdaEnv +newLambdaEnv env st = + LambdaEnv + <$> newMVar (LambdaState M.empty 0) + <*> return st + <*> return env + +{- +When invoking a function, we insert a new id to the state and then call Lambda. +-} +execute :: LambdaEnv -> Throttle -> BS.ByteString -> BackendM BS.ByteString +execute LambdaEnv{..} throttle input = do + -- Modify environment + mvar <- liftIO $ newEmptyMVar @(IO BS.ByteString) + id' <- liftIO $ modifyMVar leState $ \LambdaState{..} -> return + ( LambdaState { lsNextId = lsNextId + 1 + , lsInvocations = + M.insert lsNextId (void . tryPutMVar mvar) lsInvocations + } + , lsNextId + ) + + -- invoke the lambda function + irs <- liftIO $ throttled throttle . runResourceT . runAWS leEnv $ + send $ invoke + (siFunc leStack) + (BL.toStrict . A.encode $ A.object + [ (T.pack "d", A.toJSON . T.decodeUtf8 $ B64.encode input) + , (T.pack "i", A.toJSON id') + ]) + & iInvocationType ?~ Event + submitted + + unless (irs ^. irsStatusCode `div` 100 == 2) $ + throwIO . InvokeException $ + "Invoke failed. Status code: " <> T.pack (show $ irs ^. irsStatusCode) + + -- wait fo the answer + liftIO . join $ readMVar mvar + + +{- +And then we listen from answerQueue for the responses +-} +answerThread :: LambdaEnv -> IO () +answerThread LambdaEnv {..} = runResourceT . runAWS leEnv . forever $ do + msgs <- sqsReceiveSome $ siAnswerQueue leStack + forM_ msgs $ \msg -> do + id' <- liftIO $ decodeId msg + liftIO . modifyMVar_ leState $ \s -> + case M.updateLookupWithKey (\_ _ -> Nothing) id' (lsInvocations s) of + (Nothing, _) -> return s + (Just x, s') -> s { lsInvocations = s' } <$ x (decodeResponse msg) + where + decodeId :: Message -> IO Int + decodeId msg = + case HM.lookup "Id" (msg ^. mMessageAttributes) of + Nothing -> throwIO . InvokeException $ + "Error decoding answer: can not find Id: " <> T.pack (show msg) + Just av -> case readMaybe . T.unpack <$> av ^. mavStringValue of + Nothing -> throwIO . InvokeException $ + "Error decoding answer: empty Id." + Just Nothing -> throwIO . InvokeException $ + "Error decoding answer: can not decode Id." + Just (Just x) -> return x + + decodeResponse :: Message -> IO BS.ByteString + decodeResponse msg = + case B64.decode . T.encodeUtf8 <$> msg ^. mBody of + Nothing -> throwIO . InvokeException $ + "Error decoding answer: no body." + Just (Left err) -> throwIO . InvokeException $ + "Error decoding answer: " <> T.pack err + Just (Right x) -> return x + +{- +And then we listen from answerQueue for the responses +-} +deadLetterThread :: LambdaEnv -> IO () +deadLetterThread LambdaEnv {..} = runResourceT . runAWS leEnv . forever $ do + msgs <- sqsReceiveSome $ siDeadLetterQueue leStack + forM_ msgs $ \msg -> do + id' <- liftIO $ decodeId msg + liftIO . modifyMVar_ leState $ \s -> + case M.updateLookupWithKey (\_ _ -> Nothing) id' (lsInvocations s) of + (Nothing, _) -> return s + (Just x, s') -> s { lsInvocations = s' } <$ x failure + where + failure :: IO a + failure = throwIO . InvokeException $ "Lambda function failed." + + decodeId :: Message -> IO Int + decodeId msg = case msg ^? mBody . _Just . key "i" . _Number of + Nothing -> throwIO . InvokeException $ + "Can not find Id: " <> T.pack (show msg) + Just x -> return $ truncate x + +{- +A helper function to read from SQS queues. +-} +sqsReceiveSome :: T.Text -> AWS [Message] +sqsReceiveSome queue = do + rmrs <- send $ + receiveMessage queue + & rmVisibilityTimeout ?~ 10 + & rmWaitTimeSeconds ?~ 10 + & rmMaxNumberOfMessages ?~ 10 + & rmMessageAttributeNames .~ ["Id"] + unless (rmrs ^. rmrsResponseStatus == 200) $ + liftIO . throwIO . InvokeException $ + "Error receiving messages: " <> T.pack (show $ rmrs ^. rmrsResponseStatus) + let msgs = rmrs ^. rmrsMessages + unless (null msgs) $ do + dmbrs <- send $ deleteMessageBatch queue + & dmbEntries .~ + [ deleteMessageBatchRequestEntry + (T.pack $ show i) + (fromJust $ msg ^. mReceiptHandle) + | (i, msg) <- zip [(0::Integer)..] msgs + ] + unless (dmbrs ^. dmbrsResponseStatus == 200) $ + liftIO . throwIO . InvokeException $ + "Error deleting received messages: " <> T.pack (show $ rmrs ^. rmrsResponseStatus) + return msgs + +-------------------------------------------------------------------------------- + +withInvoke :: Env -> StackInfo -> ((BS.ByteString -> BackendM BS.ByteString) -> IO a) -> IO a +withInvoke env stack f = do + le <- newLambdaEnv env stack + throttle <- newThrottle 128 + let answerT = async $ catchAny (answerThread le) $ \ex -> print ex + deadLetterT = async $ catchAny (deadLetterThread le) $ \ex -> print ex + void . sequence $ replicate 4 answerT ++ replicate 2 deadLetterT + f $ execute le throttle + +-------------------------------------------------------------------------------- + +newtype InvokeException + = InvokeException T.Text + deriving Show + +instance Exception InvokeException diff --git a/src/Control/Distributed/Fork/Lambda/Internal/Stack.hs b/src/Control/Distributed/Fork/Lambda/Internal/Stack.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda/Internal/Stack.hs @@ -0,0 +1,308 @@ +{-# LANGUAGE NamedFieldPuns #-} +{-# LANGUAGE RecordWildCards #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE LambdaCase #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE QuasiQuotes #-} + +{- +This module creates an environment for the Lambda function. +-} + +module Control.Distributed.Fork.Lambda.Internal.Stack + ( withStack + , StackInfo (..) + , awsUploadObject + , awsObjectExists + ) where + +-------------------------------------------------------------------------------- +import Control.Exception.Safe +import Control.Monad +import Data.Aeson (Value (Object)) +import qualified Data.ByteString as BS +import qualified Data.ByteString.Lazy as BL +import qualified Data.HashMap.Strict as HM +import Data.List +import Data.Maybe +import Data.Monoid +import qualified Data.Text as T +import qualified Data.Text.Encoding as T +import Control.Lens +import Network.AWS hiding (environment) +import Network.AWS.Lambda +import qualified Network.AWS.S3 as S3 +import Network.AWS.Waiter +import qualified Stratosphere as S +import Data.Aeson.QQ +import Network.AWS.CloudFormation +-------------------------------------------------------------------------------- +import Control.Distributed.Fork.Lambda.Internal.Constants +import Control.Distributed.Fork.Lambda.Internal.Types +-------------------------------------------------------------------------------- + +{- +Our infrastructure in AWS Lambda looks like this. + +We're using CloudFormation to create all the necessary services declaratively +and delete all of them by deleting the stack. + +The components are: + +* The lambda function. + +* A role for the function: + + Lambda functions need to have a role attached. Currently we are both too + lax (we're not restricting the sqs:SendMessage permission to relevant topics) + and too strict (we're not letting user to provide a custom policy). This part + is probably the first one to change. + +* Two queues called answerQueue and deadLetterQueue + + Lambda functins have two ways to invoke them on-demand, synchronously and + asynchronously. Using the synchronous invocation is simpler, you call the API + and it returns the result. However it requires the HTTP connection to be open + for the whole time. This puts a hard-cap on the scalability since the driver + can only have so many open HTTP connections simultaneously. + + To mitigate this, we're going to use asynchronous invocation type, but use + an SQS queue (answerQueue) to gather the results. We use another queue + (deadLetterQueue) for collecting the failures. +-} +seTemplate :: StackOptions -> S.Template +seTemplate StackOptions{..} = + S.template + (S.Resources + [ S.resource "func" $ + S.LambdaFunctionProperties $ + S.lambdaFunction + (S.lambdaFunctionCode + & S.lfcS3Bucket ?~ S.Ref templateParameterS3Bucket + & S.lfcS3Key ?~ S.Ref templateParameterS3Key) + "handler.handle" + (S.GetAtt "role" "Arn") + (S.Literal S.Python27) + & S.lfTimeout ?~ S.Literal 300 + & S.lfMemorySize ?~ S.Literal (fromIntegral soLambdaMemory) + & S.lfDeadLetterConfig ?~ + S.LambdaFunctionDeadLetterConfig (Just $ S.GetAtt "deadLetterQueue" "Arn") + , S.resource "role" seRole + , S.resource "answerQueue" $ S.SQSQueueProperties S.sqsQueue + , S.resource "deadLetterQueue" $ S.SQSQueueProperties S.sqsQueue + ]) & + S.templateParameters ?~ + S.Parameters + [ S.parameter templateParameterS3Bucket "String" + , S.parameter templateParameterS3Key "String" + ] & + S.templateOutputs ?~ + S.Outputs + [ S.output templateOutputFunc (S.Ref "func") + , S.output templateOutputAnswerQueue (S.Ref "answerQueue") + , S.output templateOutputDeadLetterQueue (S.Ref "deadLetterQueue") + ] + +seRole :: S.ResourceProperties +seRole = + S.IAMRoleProperties $ + S.iamRole assumeRolePolicy + & S.iamrPolicies ?~ + [ S.iamRolePolicy sqsAccessPolicy (S.Literal "sqs") + , S.iamRolePolicy cloudwatchPolicy (S.Literal "cloudwatch") + ] + where + assumeRolePolicy = valueToObject [aesonQQ| + { + "Version":"2012-10-17", + "Statement": [{ + "Effect": "Allow", + "Principal": { + "Service": [ "lambda.amazonaws.com" ] + }, + "Action": [ "sts:AssumeRole" ] + }] + } + |] + sqsAccessPolicy = valueToObject [aesonQQ| + { + "Version": "2012-10-17", + "Statement": [{ + "Effect": "Allow", + "Action": [ + "sqs:SendMessage" + ], + "Resource": "arn:aws:sqs:*" + }] + } + |] + cloudwatchPolicy = valueToObject [aesonQQ| + { + "Version": "2012-10-17", + "Statement": [{ + "Action": [ + "logs:CreateLogGroup", + "logs:CreateLogStream", + "logs:PutLogEvents" + ], + "Effect": "Allow", + "Resource": "arn:aws:logs:*:*:*" + }] + } + |] + valueToObject = \case + Object hm -> hm + _ -> error "invariant violation" + + +templateParameterS3Bucket :: T.Text +templateParameterS3Bucket = "s3bucket" + +templateParameterS3Key :: T.Text +templateParameterS3Key = "s3key" + +templateOutputFunc :: T.Text +templateOutputFunc = "output" + +templateOutputAnswerQueue :: T.Text +templateOutputAnswerQueue = "answerQueue" + +templateOutputDeadLetterQueue :: T.Text +templateOutputDeadLetterQueue = "deadLetterQueue" + +-------------------------------------------------------------------------------- + +{- +Before creating a stack, we need to upload the artifact to S3. +-} +awsUploadObject :: S3Loc -> BS.ByteString -> AWS () +awsUploadObject (S3Loc (BucketName bucket) path) contents = do + pors <- send $ S3.putObject + (S3.BucketName bucket) + (S3.ObjectKey path) + (toBody contents) + unless (pors ^. S3.porsResponseStatus == 200) $ + throwM . StackException $ + "Upload failed. Status code: " <> T.pack (show $ pors ^. S3.porsResponseStatus) + +awsObjectExists :: S3Loc -> AWS Bool +awsObjectExists (S3Loc (BucketName bucket) path) = do + lors <- send $ + S3.listObjects (S3.BucketName bucket) + & S3.loPrefix ?~ path + unless (lors ^. S3.lorsResponseStatus == 200) $ + throwM . StackException $ + "List objects failed. Status code: " <> T.pack (show lors) + let files = map (view S3.oKey) (lors ^. S3.lorsContents) + return $ any (\(S3.ObjectKey k) -> k == path) files + +-------------------------------------------------------------------------------- + +{- +Here we are actually creating the stack. + +Tricky part is that, since our lambda function publish to answerQueue, it needs +to know the URL for it. However LambdaFunctionEnvironment in CloudFormation does +not support referring to stack variables inside, so we need to patch the function +afterwards to add the URL to the environment +-} +data StackInfo = StackInfo + { siId :: T.Text + , siFunc :: T.Text + , siAnswerQueue :: T.Text + , siDeadLetterQueue :: T.Text + } + +seCreateStack :: StackOptions -> AWS StackInfo +seCreateStack options@StackOptions { soName = StackName stackName + , soLambdaCode = S3Loc (BucketName bucketName) path} = do + csrs <- + send $ + createStack stackName + & csTemplateBody ?~ + (T.decodeUtf8 . BL.toStrict . S.encodeTemplate $ seTemplate options) + & csCapabilities .~ [CapabilityIAM] + & csParameters .~ + [ parameter + & pParameterKey ?~ templateParameterS3Bucket + & pParameterValue ?~ bucketName + , parameter + & pParameterKey ?~ templateParameterS3Key + & pParameterValue ?~ path + ] + unless (csrs ^. csrsResponseStatus == 200) $ + throwM $ + StackException + ("CloudFormation stack creation request failed." <> T.pack (show csrs)) + stackId <- + case csrs ^. csrsStackId of + Nothing -> + throwM $ + StackException + "Could not determine stack id." + Just xs -> return xs + + await stackCreateComplete (describeStacks & dStackName ?~ stackId) >>= \case + AcceptSuccess -> return () + err -> + throwM . StackException $ "CloudFormation stack creation failed." <> T.pack (show err) + + dsrs <- send $ describeStacks & dStackName ?~ stackName + unless (dsrs ^. dsrsResponseStatus == 200) $ + throwM . StackException $ + "CloudFormation describeStack failed. Status code: " + <> T.pack (show $ dsrs ^. dsrsResponseStatus) + stackRs <- case dsrs ^. dsrsStacks of + [x] -> return x + _ -> throwM $ StackException "Unexpected answer from DescribeStacks." + + func <- case lookupOutput stackRs templateOutputFunc of + Nothing -> throwM $ StackException "Could not determine function name." + Just t -> return t + + answerQueue <- case lookupOutput stackRs templateOutputAnswerQueue of + Nothing -> throwM $ StackException "Could not determine answerQueue URL." + Just t -> return t + + deadLetterQueue <- case lookupOutput stackRs templateOutputDeadLetterQueue of + Nothing -> throwM $ StackException "Could not determine deadLetterQueue URL." + Just t -> return t + + _ <- send $ + updateFunctionConfiguration func + & ufcEnvironment ?~ ( + environment + & eVariables ?~ HM.fromList [ (envAnswerQueueUrl, answerQueue) ] + ) + + return $ StackInfo { siId = stackId + , siFunc = func + , siAnswerQueue = answerQueue + , siDeadLetterQueue = deadLetterQueue + } + + where + lookupOutput :: Stack -> T.Text -> Maybe T.Text + lookupOutput st key = + fmap (\i -> fromJust $ i ^. oOutputValue) . + find (\o -> o ^. oOutputKey == Just key) $ + st ^. sOutputs + +seDeleteStack :: StackInfo -> AWS () +seDeleteStack = void . send . deleteStack . siId + +-------------------------------------------------------------------------------- + +newtype StackException + = StackException T.Text + deriving Show + +instance Exception StackException + +-------------------------------------------------------------------------------- + +withStack :: StackOptions -> Env -> (StackInfo -> IO a) -> IO a +withStack opts env = bracket create destroy + where + create = runResourceT . runAWS env $ seCreateStack opts + destroy = runResourceT . runAWS env . seDeleteStack diff --git a/src/Control/Distributed/Fork/Lambda/Internal/Types.hs b/src/Control/Distributed/Fork/Lambda/Internal/Types.hs new file mode 100644 --- /dev/null +++ b/src/Control/Distributed/Fork/Lambda/Internal/Types.hs @@ -0,0 +1,20 @@ +module Control.Distributed.Fork.Lambda.Internal.Types where + +-------------------------------------------------------------------------------- +import Data.Text (Text) +-------------------------------------------------------------------------------- + +newtype BucketName = BucketName Text + deriving (Eq, Show) + +data S3Loc = S3Loc BucketName Text + deriving (Eq, Show) + +newtype StackName = StackName { unStackName :: Text } + deriving (Eq, Show) + +data StackOptions = + StackOptions { soName :: StackName + , soLambdaMemory :: Int + , soLambdaCode :: S3Loc + } diff --git a/test/Test.hs b/test/Test.hs new file mode 100644 --- /dev/null +++ b/test/Test.hs @@ -0,0 +1,56 @@ +{-# LANGUAGE LambdaCase #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE StaticPointers #-} +{-# LANGUAGE TypeApplications #-} + +module Main where + +-------------------------------------------------------------------------------- +import Control.Concurrent +import Control.Exception (try) +import Data.Monoid ((<>)) +import qualified Data.Text as T +import System.Environment +import Test.Tasty +import Test.Tasty.HUnit +-------------------------------------------------------------------------------- +import Control.Distributed.Fork +import Control.Distributed.Fork.Lambda +-------------------------------------------------------------------------------- + +main :: IO () +main = do + initDistributedFork + tests_ <- lookupEnv "ENABLE_AWS_TESTS" >>= \case + Nothing -> do + putStrLn "ENV[ENABLE_AWS_TESTS] is not set, skipping." + return $ testGroup "No tests" [] + Just _ -> return tests + defaultMain tests_ + +opts :: LambdaBackendOptions +opts = lambdaBackendOptions "serverless-batch" + +tests :: TestTree +tests = + testGroup + "Tests" + [ testCase "creates backend" $ do + withLambdaBackend opts $ \_ -> do + threadDelay $ 5*1000*1000 + return () + , testCase "runs the function" $ do + r <- + withLambdaBackend opts $ \backend -> + fork backend (static Dict) (static (return $ Just @Integer 42)) + >>= await + r @?= Just 42 + , testCase "handles oom" $ do + r <- + try $ withLambdaBackend opts $ \backend -> + fork backend (static Dict) (static (return $ T.replicate (2^32) "h")) + >>= await + r @?= Left (ExecutorFailedException $ + "Backend threw an exception: InvokeException " <> + "\"Lambda function failed.\"") + ]