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.Kinesis.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)
--
-- Describes the specified Amazon Kinesis stream.
--
-- The information about the stream includes its current status, its Amazon Resource Name (ARN), and an array of shard objects. For each shard object, there is information about the hash key and sequence number ranges that the shard spans, and the IDs of any earlier shards that played in a role in creating the shard. A sequence number is the identifier associated with every record ingested in the stream. The sequence number is assigned when a record is put into the stream.
--
-- You can limit the number of returned shards using the 'Limit' parameter. The number of shards in a stream may be too large to return from a single call to 'DescribeStream'. You can detect this by using the 'HasMoreShards' flag in the returned output. 'HasMoreShards' is set to 'true' when there is more data available.
--
-- 'DescribeStream' is a paginated operation. If there are more shards available, you can request them using the shard ID of the last shard returned. Specify this ID in the 'ExclusiveStartShardId' parameter in a subsequent request to 'DescribeStream'.
--
-- There are no guarantees about the chronological order shards returned in 'DescribeStream' results. If you want to process shards in chronological order, use 'ParentShardId' to track lineage to the oldest shard.
--
-- < DescribeStream> has a limit of 10 transactions per second per account.
--
-- This operation returns paginated results.
module Network.AWS.Kinesis.DescribeStream
    (
    -- * Creating a Request
      describeStream
    , DescribeStream
    -- * Request Lenses
    , dExclusiveStartShardId
    , dLimit
    , dStreamName

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

import           Network.AWS.Kinesis.Types
import           Network.AWS.Kinesis.Types.Product
import           Network.AWS.Lens
import           Network.AWS.Pager
import           Network.AWS.Prelude
import           Network.AWS.Request
import           Network.AWS.Response

-- | Represents the input for 'DescribeStream'.
--
-- /See:/ 'describeStream' smart constructor.
data DescribeStream = DescribeStream'
    { _dExclusiveStartShardId :: !(Maybe Text)
    , _dLimit                 :: !(Maybe Nat)
    , _dStreamName            :: !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:
--
-- * 'dExclusiveStartShardId'
--
-- * 'dLimit'
--
-- * 'dStreamName'
describeStream
    :: Text -- ^ 'dStreamName'
    -> DescribeStream
describeStream pStreamName_ =
    DescribeStream'
    { _dExclusiveStartShardId = Nothing
    , _dLimit = Nothing
    , _dStreamName = pStreamName_
    }

-- | The shard ID of the shard to start with.
dExclusiveStartShardId :: Lens' DescribeStream (Maybe Text)
dExclusiveStartShardId = lens _dExclusiveStartShardId (\ s a -> s{_dExclusiveStartShardId = a});

-- | The maximum number of shards to return.
dLimit :: Lens' DescribeStream (Maybe Natural)
dLimit = lens _dLimit (\ s a -> s{_dLimit = a}) . mapping _Nat;

-- | The name of the stream to describe.
dStreamName :: Lens' DescribeStream Text
dStreamName = lens _dStreamName (\ s a -> s{_dStreamName = a});

instance AWSPager DescribeStream where
        page rq rs
          | stop
              (rs ^. dsrsStreamDescription . sdHasMoreShards)
            = Nothing
          | isNothing
              (rs ^?
                 dsrsStreamDescription . sdShards . _last . sShardId)
            = Nothing
          | otherwise =
            Just $ rq &
              dExclusiveStartShardId .~
                rs ^?
                  dsrsStreamDescription . sdShards . _last . sShardId

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

instance Hashable DescribeStream

instance NFData DescribeStream

instance ToHeaders DescribeStream where
        toHeaders
          = const
              (mconcat
                 ["X-Amz-Target" =#
                    ("Kinesis_20131202.DescribeStream" :: ByteString),
                  "Content-Type" =#
                    ("application/x-amz-json-1.1" :: ByteString)])

instance ToJSON DescribeStream where
        toJSON DescribeStream'{..}
          = object
              (catMaybes
                 [("ExclusiveStartShardId" .=) <$>
                    _dExclusiveStartShardId,
                  ("Limit" .=) <$> _dLimit,
                  Just ("StreamName" .= _dStreamName)])

instance ToPath DescribeStream where
        toPath = const "/"

instance ToQuery DescribeStream where
        toQuery = const mempty

-- | Represents the output for 'DescribeStream'.
--
-- /See:/ 'describeStreamResponse' smart constructor.
data DescribeStreamResponse = DescribeStreamResponse'
    { _dsrsResponseStatus    :: !Int
    , _dsrsStreamDescription :: !StreamDescription
    } 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:
--
-- * 'dsrsResponseStatus'
--
-- * 'dsrsStreamDescription'
describeStreamResponse
    :: Int -- ^ 'dsrsResponseStatus'
    -> StreamDescription -- ^ 'dsrsStreamDescription'
    -> DescribeStreamResponse
describeStreamResponse pResponseStatus_ pStreamDescription_ =
    DescribeStreamResponse'
    { _dsrsResponseStatus = pResponseStatus_
    , _dsrsStreamDescription = pStreamDescription_
    }

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

-- | The current status of the stream, the stream ARN, an array of shard objects that comprise the stream, and states whether there are more shards available.
dsrsStreamDescription :: Lens' DescribeStreamResponse StreamDescription
dsrsStreamDescription = lens _dsrsStreamDescription (\ s a -> s{_dsrsStreamDescription = a});

instance NFData DescribeStreamResponse