{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DuplicateRecordFields #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE StrictData #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# OPTIONS_GHC -fno-warn-unused-binds #-}
{-# OPTIONS_GHC -fno-warn-unused-imports #-}
{-# OPTIONS_GHC -fno-warn-unused-matches #-}

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

-- |
-- Module      : Amazonka.AutoScaling.DescribeLoadBalancers
-- Copyright   : (c) 2013-2023 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay
-- Stability   : auto-generated
-- Portability : non-portable (GHC extensions)
--
-- Gets information about the load balancers for the specified Auto Scaling
-- group.
--
-- This operation describes only Classic Load Balancers. If you have
-- Application Load Balancers, Network Load Balancers, or Gateway Load
-- Balancer, use the DescribeLoadBalancerTargetGroups API instead.
--
-- To determine the attachment status of the load balancer, use the @State@
-- element in the response. When you attach a load balancer to an Auto
-- Scaling group, the initial @State@ value is @Adding@. The state
-- transitions to @Added@ after all Auto Scaling instances are registered
-- with the load balancer. If Elastic Load Balancing health checks are
-- enabled for the Auto Scaling group, the state transitions to @InService@
-- after at least one Auto Scaling instance passes the health check. When
-- the load balancer is in the @InService@ state, Amazon EC2 Auto Scaling
-- can terminate and replace any instances that are reported as unhealthy.
-- If no registered instances pass the health checks, the load balancer
-- doesn\'t enter the @InService@ state.
--
-- Load balancers also have an @InService@ state if you attach them in the
-- CreateAutoScalingGroup API call. If your load balancer state is
-- @InService@, but it is not working properly, check the scaling
-- activities by calling DescribeScalingActivities and take any corrective
-- actions necessary.
--
-- For help with failed health checks, see
-- <https://docs.aws.amazon.com/autoscaling/ec2/userguide/ts-as-healthchecks.html Troubleshooting Amazon EC2 Auto Scaling: Health checks>
-- in the /Amazon EC2 Auto Scaling User Guide/. For more information, see
-- <https://docs.aws.amazon.com/autoscaling/ec2/userguide/autoscaling-load-balancer.html Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group>
-- in the /Amazon EC2 Auto Scaling User Guide/.
--
-- This operation returns paginated results.
module Amazonka.AutoScaling.DescribeLoadBalancers
  ( -- * Creating a Request
    DescribeLoadBalancers (..),
    newDescribeLoadBalancers,

    -- * Request Lenses
    describeLoadBalancers_maxRecords,
    describeLoadBalancers_nextToken,
    describeLoadBalancers_autoScalingGroupName,

    -- * Destructuring the Response
    DescribeLoadBalancersResponse (..),
    newDescribeLoadBalancersResponse,

    -- * Response Lenses
    describeLoadBalancersResponse_loadBalancers,
    describeLoadBalancersResponse_nextToken,
    describeLoadBalancersResponse_httpStatus,
  )
where

import Amazonka.AutoScaling.Types
import qualified Amazonka.Core as Core
import qualified Amazonka.Core.Lens.Internal as Lens
import qualified Amazonka.Data as Data
import qualified Amazonka.Prelude as Prelude
import qualified Amazonka.Request as Request
import qualified Amazonka.Response as Response

-- | /See:/ 'newDescribeLoadBalancers' smart constructor.
data DescribeLoadBalancers = DescribeLoadBalancers'
  { -- | The maximum number of items to return with this call. The default value
    -- is @100@ and the maximum value is @100@.
    maxRecords :: Prelude.Maybe Prelude.Int,
    -- | The token for the next set of items to return. (You received this token
    -- from a previous call.)
    nextToken :: Prelude.Maybe Prelude.Text,
    -- | The name of the Auto Scaling group.
    autoScalingGroupName :: Prelude.Text
  }
  deriving (Prelude.Eq, Prelude.Read, Prelude.Show, Prelude.Generic)

-- |
-- Create a value of 'DescribeLoadBalancers' with all optional fields omitted.
--
-- Use <https://hackage.haskell.org/package/generic-lens generic-lens> or <https://hackage.haskell.org/package/optics optics> to modify other optional fields.
--
-- The following record fields are available, with the corresponding lenses provided
-- for backwards compatibility:
--
-- 'maxRecords', 'describeLoadBalancers_maxRecords' - The maximum number of items to return with this call. The default value
-- is @100@ and the maximum value is @100@.
--
-- 'nextToken', 'describeLoadBalancers_nextToken' - The token for the next set of items to return. (You received this token
-- from a previous call.)
--
-- 'autoScalingGroupName', 'describeLoadBalancers_autoScalingGroupName' - The name of the Auto Scaling group.
newDescribeLoadBalancers ::
  -- | 'autoScalingGroupName'
  Prelude.Text ->
  DescribeLoadBalancers
newDescribeLoadBalancers pAutoScalingGroupName_ =
  DescribeLoadBalancers'
    { maxRecords =
        Prelude.Nothing,
      nextToken = Prelude.Nothing,
      autoScalingGroupName = pAutoScalingGroupName_
    }

-- | The maximum number of items to return with this call. The default value
-- is @100@ and the maximum value is @100@.
describeLoadBalancers_maxRecords :: Lens.Lens' DescribeLoadBalancers (Prelude.Maybe Prelude.Int)
describeLoadBalancers_maxRecords = Lens.lens (\DescribeLoadBalancers' {maxRecords} -> maxRecords) (\s@DescribeLoadBalancers' {} a -> s {maxRecords = a} :: DescribeLoadBalancers)

-- | The token for the next set of items to return. (You received this token
-- from a previous call.)
describeLoadBalancers_nextToken :: Lens.Lens' DescribeLoadBalancers (Prelude.Maybe Prelude.Text)
describeLoadBalancers_nextToken = Lens.lens (\DescribeLoadBalancers' {nextToken} -> nextToken) (\s@DescribeLoadBalancers' {} a -> s {nextToken = a} :: DescribeLoadBalancers)

-- | The name of the Auto Scaling group.
describeLoadBalancers_autoScalingGroupName :: Lens.Lens' DescribeLoadBalancers Prelude.Text
describeLoadBalancers_autoScalingGroupName = Lens.lens (\DescribeLoadBalancers' {autoScalingGroupName} -> autoScalingGroupName) (\s@DescribeLoadBalancers' {} a -> s {autoScalingGroupName = a} :: DescribeLoadBalancers)

instance Core.AWSPager DescribeLoadBalancers where
  page rq rs
    | Core.stop
        ( rs
            Lens.^? describeLoadBalancersResponse_nextToken
            Prelude.. Lens._Just
        ) =
        Prelude.Nothing
    | Core.stop
        ( rs
            Lens.^? describeLoadBalancersResponse_loadBalancers
            Prelude.. Lens._Just
        ) =
        Prelude.Nothing
    | Prelude.otherwise =
        Prelude.Just
          Prelude.$ rq
          Prelude.& describeLoadBalancers_nextToken
          Lens..~ rs
          Lens.^? describeLoadBalancersResponse_nextToken
          Prelude.. Lens._Just

instance Core.AWSRequest DescribeLoadBalancers where
  type
    AWSResponse DescribeLoadBalancers =
      DescribeLoadBalancersResponse
  request overrides =
    Request.postQuery (overrides defaultService)
  response =
    Response.receiveXMLWrapper
      "DescribeLoadBalancersResult"
      ( \s h x ->
          DescribeLoadBalancersResponse'
            Prelude.<$> ( x
                            Data..@? "LoadBalancers"
                            Core..!@ Prelude.mempty
                            Prelude.>>= Core.may (Data.parseXMLList "member")
                        )
            Prelude.<*> (x Data..@? "NextToken")
            Prelude.<*> (Prelude.pure (Prelude.fromEnum s))
      )

instance Prelude.Hashable DescribeLoadBalancers where
  hashWithSalt _salt DescribeLoadBalancers' {..} =
    _salt
      `Prelude.hashWithSalt` maxRecords
      `Prelude.hashWithSalt` nextToken
      `Prelude.hashWithSalt` autoScalingGroupName

instance Prelude.NFData DescribeLoadBalancers where
  rnf DescribeLoadBalancers' {..} =
    Prelude.rnf maxRecords
      `Prelude.seq` Prelude.rnf nextToken
      `Prelude.seq` Prelude.rnf autoScalingGroupName

instance Data.ToHeaders DescribeLoadBalancers where
  toHeaders = Prelude.const Prelude.mempty

instance Data.ToPath DescribeLoadBalancers where
  toPath = Prelude.const "/"

instance Data.ToQuery DescribeLoadBalancers where
  toQuery DescribeLoadBalancers' {..} =
    Prelude.mconcat
      [ "Action"
          Data.=: ("DescribeLoadBalancers" :: Prelude.ByteString),
        "Version"
          Data.=: ("2011-01-01" :: Prelude.ByteString),
        "MaxRecords" Data.=: maxRecords,
        "NextToken" Data.=: nextToken,
        "AutoScalingGroupName" Data.=: autoScalingGroupName
      ]

-- | /See:/ 'newDescribeLoadBalancersResponse' smart constructor.
data DescribeLoadBalancersResponse = DescribeLoadBalancersResponse'
  { -- | The load balancers.
    loadBalancers :: Prelude.Maybe [LoadBalancerState],
    -- | A string that indicates that the response contains more items than can
    -- be returned in a single response. To receive additional items, specify
    -- this string for the @NextToken@ value when requesting the next set of
    -- items. This value is null when there are no more items to return.
    nextToken :: Prelude.Maybe Prelude.Text,
    -- | The response's http status code.
    httpStatus :: Prelude.Int
  }
  deriving (Prelude.Eq, Prelude.Read, Prelude.Show, Prelude.Generic)

-- |
-- Create a value of 'DescribeLoadBalancersResponse' with all optional fields omitted.
--
-- Use <https://hackage.haskell.org/package/generic-lens generic-lens> or <https://hackage.haskell.org/package/optics optics> to modify other optional fields.
--
-- The following record fields are available, with the corresponding lenses provided
-- for backwards compatibility:
--
-- 'loadBalancers', 'describeLoadBalancersResponse_loadBalancers' - The load balancers.
--
-- 'nextToken', 'describeLoadBalancersResponse_nextToken' - A string that indicates that the response contains more items than can
-- be returned in a single response. To receive additional items, specify
-- this string for the @NextToken@ value when requesting the next set of
-- items. This value is null when there are no more items to return.
--
-- 'httpStatus', 'describeLoadBalancersResponse_httpStatus' - The response's http status code.
newDescribeLoadBalancersResponse ::
  -- | 'httpStatus'
  Prelude.Int ->
  DescribeLoadBalancersResponse
newDescribeLoadBalancersResponse pHttpStatus_ =
  DescribeLoadBalancersResponse'
    { loadBalancers =
        Prelude.Nothing,
      nextToken = Prelude.Nothing,
      httpStatus = pHttpStatus_
    }

-- | The load balancers.
describeLoadBalancersResponse_loadBalancers :: Lens.Lens' DescribeLoadBalancersResponse (Prelude.Maybe [LoadBalancerState])
describeLoadBalancersResponse_loadBalancers = Lens.lens (\DescribeLoadBalancersResponse' {loadBalancers} -> loadBalancers) (\s@DescribeLoadBalancersResponse' {} a -> s {loadBalancers = a} :: DescribeLoadBalancersResponse) Prelude.. Lens.mapping Lens.coerced

-- | A string that indicates that the response contains more items than can
-- be returned in a single response. To receive additional items, specify
-- this string for the @NextToken@ value when requesting the next set of
-- items. This value is null when there are no more items to return.
describeLoadBalancersResponse_nextToken :: Lens.Lens' DescribeLoadBalancersResponse (Prelude.Maybe Prelude.Text)
describeLoadBalancersResponse_nextToken = Lens.lens (\DescribeLoadBalancersResponse' {nextToken} -> nextToken) (\s@DescribeLoadBalancersResponse' {} a -> s {nextToken = a} :: DescribeLoadBalancersResponse)

-- | The response's http status code.
describeLoadBalancersResponse_httpStatus :: Lens.Lens' DescribeLoadBalancersResponse Prelude.Int
describeLoadBalancersResponse_httpStatus = Lens.lens (\DescribeLoadBalancersResponse' {httpStatus} -> httpStatus) (\s@DescribeLoadBalancersResponse' {} a -> s {httpStatus = a} :: DescribeLoadBalancersResponse)

instance Prelude.NFData DescribeLoadBalancersResponse where
  rnf DescribeLoadBalancersResponse' {..} =
    Prelude.rnf loadBalancers
      `Prelude.seq` Prelude.rnf nextToken
      `Prelude.seq` Prelude.rnf httpStatus