DescribeStream.hs

{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric      #-}
{-# LANGUAGE OverloadedStrings  #-}
{-# LANGUAGE RecordWildCards    #-}
{-# LANGUAGE TypeFamilies       #-}

{-# OPTIONS_GHC -fno-warn-unused-imports #-}
{-# OPTIONS_GHC -fno-warn-unused-binds   #-}
{-# OPTIONS_GHC -fno-warn-unused-matches #-}

-- Derived from AWS service descriptions, licensed under Apache 2.0.

-- |
-- Module      : Network.AWS.DynamoDBStreams.DescribeStream
-- Copyright   : (c) 2013-2016 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay <brendan.g.hay@gmail.com>
-- Stability   : auto-generated
-- Portability : non-portable (GHC extensions)
--
-- Returns information about a stream, including the current status of the
-- stream, its Amazon Resource Name (ARN), the composition of its shards,
-- and its corresponding DynamoDB table.
--
-- You can call /DescribeStream/ at a maximum rate of 10 times per second.
--
-- Each shard in the stream has a 'SequenceNumberRange' associated with it.
-- If the 'SequenceNumberRange' has a 'StartingSequenceNumber' but no
-- 'EndingSequenceNumber', then the shard is still open (able to receive
-- more stream records). If both 'StartingSequenceNumber' and
-- 'EndingSequenceNumber' are present, the that shared is closed and can no
-- longer receive more data.
module Network.AWS.DynamoDBStreams.DescribeStream
    (
    -- * Creating a Request
      describeStream
    , DescribeStream
    -- * Request Lenses
    , dsExclusiveStartShardId
    , dsLimit
    , dsStreamARN

    -- * Destructuring the Response
    , describeStreamResponse
    , DescribeStreamResponse
    -- * Response Lenses
    , dsrsStreamDescription
    , dsrsResponseStatus
    ) where

import           Network.AWS.DynamoDBStreams.Types
import           Network.AWS.DynamoDBStreams.Types.Product
import           Network.AWS.Lens
import           Network.AWS.Prelude
import           Network.AWS.Request
import           Network.AWS.Response

-- | Represents the input of a /DescribeStream/ operation.
--
-- /See:/ 'describeStream' smart constructor.
data DescribeStream = DescribeStream'
    { _dsExclusiveStartShardId :: !(Maybe Text)
    , _dsLimit                 :: !(Maybe Nat)
    , _dsStreamARN             :: !Text
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'DescribeStream' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'dsExclusiveStartShardId'
--
-- * 'dsLimit'
--
-- * 'dsStreamARN'
describeStream
    :: Text -- ^ 'dsStreamARN'
    -> DescribeStream
describeStream pStreamARN_ =
    DescribeStream'
    { _dsExclusiveStartShardId = Nothing
    , _dsLimit = Nothing
    , _dsStreamARN = pStreamARN_
    }

-- | The shard ID of the first item that this operation will evaluate. Use
-- the value that was returned for 'LastEvaluatedShardId' in the previous
-- operation.
dsExclusiveStartShardId :: Lens' DescribeStream (Maybe Text)
dsExclusiveStartShardId = lens _dsExclusiveStartShardId (\ s a -> s{_dsExclusiveStartShardId = a});

-- | The maximum number of shard objects to return. The upper limit is 100.
dsLimit :: Lens' DescribeStream (Maybe Natural)
dsLimit = lens _dsLimit (\ s a -> s{_dsLimit = a}) . mapping _Nat;

-- | The Amazon Resource Name (ARN) for the stream.
dsStreamARN :: Lens' DescribeStream Text
dsStreamARN = lens _dsStreamARN (\ s a -> s{_dsStreamARN = a});

instance AWSRequest DescribeStream where
        type Rs DescribeStream = DescribeStreamResponse
        request = postJSON dynamoDBStreams
        response
          = receiveJSON
              (\ s h x ->
                 DescribeStreamResponse' <$>
                   (x .?> "StreamDescription") <*> (pure (fromEnum s)))

instance Hashable DescribeStream

instance ToHeaders DescribeStream where
        toHeaders
          = const
              (mconcat
                 ["X-Amz-Target" =#
                    ("DynamoDBStreams_20120810.DescribeStream" ::
                       ByteString),
                  "Content-Type" =#
                    ("application/x-amz-json-1.0" :: ByteString)])

instance ToJSON DescribeStream where
        toJSON DescribeStream'{..}
          = object
              (catMaybes
                 [("ExclusiveStartShardId" .=) <$>
                    _dsExclusiveStartShardId,
                  ("Limit" .=) <$> _dsLimit,
                  Just ("StreamArn" .= _dsStreamARN)])

instance ToPath DescribeStream where
        toPath = const "/"

instance ToQuery DescribeStream where
        toQuery = const mempty

-- | Represents the output of a /DescribeStream/ operation.
--
-- /See:/ 'describeStreamResponse' smart constructor.
data DescribeStreamResponse = DescribeStreamResponse'
    { _dsrsStreamDescription :: !(Maybe StreamDescription)
    , _dsrsResponseStatus    :: !Int
    } deriving (Eq,Read,Show,Data,Typeable,Generic)

-- | Creates a value of 'DescribeStreamResponse' with the minimum fields required to make a request.
--
-- Use one of the following lenses to modify other fields as desired:
--
-- * 'dsrsStreamDescription'
--
-- * 'dsrsResponseStatus'
describeStreamResponse
    :: Int -- ^ 'dsrsResponseStatus'
    -> DescribeStreamResponse
describeStreamResponse pResponseStatus_ =
    DescribeStreamResponse'
    { _dsrsStreamDescription = Nothing
    , _dsrsResponseStatus = pResponseStatus_
    }

-- | A complete description of the stream, including its creation date and
-- time, the DynamoDB table associated with the stream, the shard IDs
-- within the stream, and the beginning and ending sequence numbers of
-- stream records within the shards.
dsrsStreamDescription :: Lens' DescribeStreamResponse (Maybe StreamDescription)
dsrsStreamDescription = lens _dsrsStreamDescription (\ s a -> s{_dsrsStreamDescription = a});

-- | The response status code.
dsrsResponseStatus :: Lens' DescribeStreamResponse Int
dsrsResponseStatus = lens _dsrsResponseStatus (\ s a -> s{_dsrsResponseStatus = a});