-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | AWS Lambda backend for distributed-fork.
--   
--   <a>AWS Lambda</a> backend for <a>distributed-fork</a>.
@package distributed-fork-aws-lambda
@version 0.0.2.0


-- | Provides a <a>Backend</a> using AWS Lambda functions.
--   
--   In order to do that, roughly:
--   
--   <ul>
--   <li>It creates a deployment archive containing the program binary and
--   a tiny wrapper written in Python and uploads it to the given S3
--   bucket.</li>
--   <li>Creates a CloudFormation stack containing the Lambda function and
--   an SQS queue to gather the answers.</li>
--   <li>It starts polling the SQS queue for any answers.</li>
--   <li>When executing, it invokes the Lambda function using asynchronous
--   invocation mode and blocks until a message appears in the queue.</li>
--   <li>On exit, it deletes the CloudFormation stack.</li>
--   </ul>
--   
--   Some warts:
--   
--   <ul>
--   <li>The same binary should run on AWS Lambda. In practice, this
--   means:<ul><li>You have to build and use this library on a Linux
--   machine.</li><li>You have to statically link everything. You can use
--   GHC's '<tt>-static -optl-static -optl-pthread -fPIC</tt>' parameters
--   for that. See <a>examples/examples.cabal#L16</a> for an
--   example.</li></ul></li>
--   <li>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.</li>
--   <li>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.</li>
--   </ul>
module Control.Distributed.Fork.Lambda

-- | Provides a <a>Backend</a> using AWS Lambda functions.
--   
--   Created AWS resources except the uploaded deployment package will be
--   cleaned up when exiting.
--   
--   Example usage:
--   
--   <pre>
--   {-# LANGUAGE StaticPointers #-}
--   
--   import Control.Lens
--   import Control.Distributed.Fork
--   import Control.Distributed.Fork.Lambda
--   
--   opts :: LambdaBackendOptions
--   opts = lambdaBackendOptions "my-s3-bucket"
--            &amp; lboMemory .~ 1024
--   
--   main :: IO ()
--   main = do
--     <tt>initDistributedFork</tt>
--     <a>withLambdaBackend</a> opts $ \backend -&gt; do
--       handle &lt;- <tt>fork</tt> backend (static Dict) (static (return "Hello from Lambda!"))
--       await handle &gt;&gt;= putStrLn
--   </pre>
withLambdaBackend :: LambdaBackendOptions -> (Backend -> IO a) -> IO a

-- | Options required for creating a Lambda backend.
--   
--   Use <a>lambdaBackendOptions</a> smart constructor to create and lenses
--   below for setting optional fields.
data LambdaBackendOptions
lambdaBackendOptions :: Text -> LambdaBackendOptions

-- | Prefix to the deployment archive and the CloudFormation stack.
--   
--   Default: "distributed-fork"
lboPrefix :: Lens' LambdaBackendOptions Text

-- | Desired memory for the Lambda functions.
--   
--   See <a>CloudFormation's AWS::Lambda::Function::MemorySize page</a> for
--   allowed values.
--   
--   Default: 128
lboMemory :: Lens' LambdaBackendOptions Int