Class: LogStash::Inputs::S3SQS

Inherits:
Threadable
  • Object
show all
Includes:
PluginMixins::AwsConfig::V2
Defined in:
lib/logstash/inputs/s3sqs.rb

Overview

Get logs from AWS s3 buckets as issued by an object-created event via sqs.

This plugin is based on the logstash-input-sqs plugin but doesn’t log the sqs event itself. Instead it assumes, that the event is an s3 object-created event and will then download and process the given file.

Some issues of logstash-input-sqs, like logstash not shutting down properly, have been fixed for this plugin.

In contrast to logstash-input-sqs this plugin uses the “Receive Message Wait Time” configured for the sqs queue in question, a good value will be something like 10 seconds to ensure a reasonable shutdown time of logstash. Also use a “Default Visibility Timeout” that is high enough for log files to be downloaded and processed (I think a good value should be 5-10 minutes for most use cases), the plugin will avoid removing the event from the queue if the associated log file couldn’t be correctly passed to the processing level of logstash (e.g. downloaded content size doesn’t match sqs event).

This plugin is meant for high availability setups, in contrast to logstash-input-s3 you can safely use multiple logstash nodes, since the usage of sqs will ensure that each logfile is processed only once and no file will get lost on node failure or downscaling for auto-scaling groups. (You should use a “Message Retention Period” >= 4 days for your sqs to ensure you can survive a weekend of faulty log file processing) The plugin will not delete objects from s3 buckets, so make sure to have a reasonable “Lifecycle” configured for your buckets, which should keep the files at least “Message Retention Period” days.

A typical setup will contain some s3 buckets containing elb, cloudtrail or other log files. These will be configured to send object-created events to a sqs queue, which will be configured as the source queue for this plugin. (The plugin supports gzipped content if it is marked with “contend-encoding: gzip” as it is the case for cloudtrail logs)

The logstash node therefore must have sqs permissions + the permissions to download objects from the s3 buckets that send events to the queue. (If logstash nodes are running on EC2 you should use a ServerRole to provide permissions)

source,json

{

"Version": "2012-10-17",
"Statement": [
    {
        "Effect": "Allow",
        "Action": [
            "sqs:Get*",
            "sqs:List*",
            "sqs:ReceiveMessage",
            "sqs:ChangeMessageVisibility*",
            "sqs:DeleteMessage*"
        ],
        "Resource": [
            "arn:aws:sqs:us-east-1:123456789012:my-elb-log-queue"
        ]
    },
    {
        "Effect": "Allow",
        "Action": [
            "s3:Get*",
            "s3:List*"
        ],
        "Resource": [
            "arn:aws:s3:::my-elb-logs",
            "arn:aws:s3:::my-elb-logs/*"
        ]
    }
]

}

Constant Summary collapse

BACKOFF_SLEEP_TIME = 
1
BACKOFF_FACTOR = 
2
MAX_TIME_BEFORE_GIVING_UP = 
60
EVENT_SOURCE = 
'aws:s3'
EVENT_TYPE = 
'ObjectCreated'

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#poller ⇒ Object (readonly)

Returns the value of attribute poller.



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# File 'lib/logstash/inputs/s3sqs.rb', line 90

def poller
  @poller
end

#s3 ⇒ Object (readonly)

Returns the value of attribute s3.



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# File 'lib/logstash/inputs/s3sqs.rb', line 91

def s3
  @s3
end

Instance Method Details

#handle_message(message, queue) ⇒ Object 



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# File 'lib/logstash/inputs/s3sqs.rb', line 121

def handle_message(message, queue)
  hash = JSON.parse message.body
  # there may be test events sent from the s3 bucket which won't contain a Records array,
  # we will skip those events and remove them from queue
  if hash['Records'] then
    # typically there will be only 1 record per event, but since it is an array we will
    # treat it as if there could be more records
    hash['Records'].each do |record|
      # in case there are any events with Records that aren't s3 object-created events and can't therefore be
      # processed by this plugin, we will skip them and remove them from queue
      if record['eventSource'] == EVENT_SOURCE and record['eventName'].start_with?(EVENT_TYPE) then
        # try download and :skip_delete if it fails
        begin
          response = @s3.get_object(
            bucket: record['s3']['bucket']['name'],
            key: record['s3']['object']['key']
          )
        rescue => e
          @logger.warn("issuing :skip_delete on failed download", :bucket => record['s3']['bucket']['name'], :object => record['s3']['object']['key'], :error => e)
          throw :skip_delete
        end
        # verify downloaded content size
        if response.content_length == record['s3']['object']['size'] then
          body = response.body
          # if necessary unzip
          if response.content_encoding == "gzip" or record['s3']['object']['key'].end_with?(".gz") then
            begin
            temp = Zlib::GzipReader.new(body)
            rescue => e
              @logger.warn("content is marked to be gzipped but can't unzip it, assuming plain text", :bucket => record['s3']['bucket']['name'], :object => record['s3']['object']['key'], :error => e)
              temp = body
            end
            body = temp
          end
          # process the plain text content
          begin
            lines = body.read.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: "\u2370").split(/\n/)
            lines.each do |line|
              @codec.decode(line) do |event|
                decorate(event)

                event['[@metadata][s3_bucket_name]'] = record['s3']['bucket']['name']
                event['[@metadata][s3_object_key]']  = record['s3']['object']['key']

                queue << event
              end
            end
          rescue => e
            @logger.warn("issuing :skip_delete on failed plain text processing", :bucket => record['s3']['bucket']['name'], :object => record['s3']['object']['key'], :error => e)
            throw :skip_delete
          end
        # otherwise try again later
        else
          @logger.warn("issuing :skip_delete on wrong download content size", :bucket => record['s3']['bucket']['name'], :object => record['s3']['object']['key'],
            :download_size => response.content_length, :expected => record['s3']['object']['size'])
          throw :skip_delete
        end
      end
    end
  end
end

#polling_options ⇒ Object 



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# File 'lib/logstash/inputs/s3sqs.rb', line 109

def polling_options
  {
    # we will query 1 message at a time, so we can ensure correct error handling if we can't download a single file correctly
    # (we will throw :skip_delete if download size isn't correct to process the event again later
    # -> set a reasonable "Default Visibility Timeout" for your queue, so that there's enough time to process the log files)
    :max_number_of_messages => 1,
    # we will use the queue's setting, a good value is 10 seconds
    # (to ensure fast logstash shutdown on the one hand and few api calls on the other hand)
    :wait_time_seconds => nil,
  }
end

#register ⇒ Object 



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# File 'lib/logstash/inputs/s3sqs.rb', line 93

def register
  require "aws-sdk"
  @logger.info("Registering SQS input", :queue => @queue)
  setup_queue
end

#run(queue) ⇒ Object 



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# File 'lib/logstash/inputs/s3sqs.rb', line 183

def run(queue)
  # ensure we can stop logstash correctly
  poller.before_request do |stats|
    if stop? then
      @logger.warn("issuing :stop_polling on stop?", :queue => @queue)
      # this can take up to "Receive Message Wait Time" (of the sqs queue) seconds to be recognized
      throw :stop_polling
    end
  end
  # poll a message and process it
  run_with_backoff do
    poller.poll(polling_options) do |message|
      handle_message(message, queue)
    end
  end
end

#setup_queue ⇒ Object 



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# File 'lib/logstash/inputs/s3sqs.rb', line 99

def setup_queue
  aws_sqs_client = Aws::SQS::Client.new(aws_options_hash)
  queue_url = aws_sqs_client.get_queue_url(:queue_name =>  @queue)[:queue_url]
  @poller = Aws::SQS::QueuePoller.new(queue_url, :client => aws_sqs_client)
  @s3 = Aws::S3::Client.new(aws_options_hash)
rescue Aws::SQS::Errors::ServiceError => e
  @logger.error("Cannot establish connection to Amazon SQS", :error => e)
  raise LogStash::ConfigurationError, "Verify the SQS queue name and your credentials"
end