Google_pubsub input plugin

  • Plugin version: v1.2.1
  • Released on: 2018-08-17
  • Changelog

For other versions, see theVersioned plugin docs.

Installation

For plugins not bundled by default, it is easy to install by running bin/logstash-plugin install logstash-input-google_pubsub. See Working with plugins for more details.

Getting Help

For questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github.For the list of Elastic supported plugins, please consult the Elastic Support Matrix.

Description

Author: Eric Johnson <erjohnso@google.com>Date: 2016-06-01

Copyright 2016 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");you may not use this file except in compliance with the License.You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, softwaredistributed under the License is distributed on an "AS IS" BASIS,WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.See the License for the specific language governing permissions andlimitations under the License.Google depsThis is a Logstash input plugin forGoogle Pub/Sub. The plugin can subscribeto a topic and ingest messages.

The main motivation behind the development of this plugin was to ingestStackdriver Logging messages via theExported Logsfeature of Stackdriver Logging.

Prerequisites

You must first create a Google Cloud Platform project and enable theGoogle Pub/Sub API. If you intend to use the plugin ingest Stackdriver Loggingmessages, you must also enable the Stackdriver Logging API and configure logexporting to Pub/Sub. There is plentiful information onhttps://cloud.google.com/ to get started:

Cloud Pub/Sub

Currently, this module requires you to create a topic manually and specifyit in the logstash config file. You must also specify a subscription, butthe plugin will attempt to create the pull-based subscription on its own.

All messages received from Pub/Sub will be converted to a logstash eventand added to the processing pipeline queue. All Pub/Sub messages will beacknowledged and removed from the Pub/Sub topic (please see more aboutPub/Sub concepts.

It is generally assumed that incoming messages will be in JSON and added tothe logstash event as-is. However, if a plain text message is received, theplugin will return the raw text in as raw_message in the logstash event.

Authentication

You have two options for authentication depending on where you run Logstash.

  1. If you are running Logstash outside of Google Cloud Platform, then you willneed to create a Google Cloud Platform Service Account and specify the fullpath to the JSON private key file in your config. You must assign sufficientroles to the Service Account to create a subscription and to pull messagesfrom the subscription. Learn more about GCP Service Accounts and IAM roleshere:

  2. If you are running Logstash on a Google Compute Engine instance, you may optto use Application Default Credentials. In this case, you will not need tospecify a JSON private key file in your config.

Stackdriver Logging (optional)

If you intend to use the logstash plugin for Stackdriver Logging messageingestion, you must first manually set up the Export option to Cloud Pub/Sub andthe manually create the topic. Please see the more detailed instructions at,https://cloud.google.com/logging/docs/export/using_exported_logs [Exported Logs]and ensure that the necessary permissionshave also been manually configured.

Logging messages from Stackdriver Logging exported to Pub/Sub are received asJSON and converted to a logstash event as-is inthis format.

Sample Configuration

Below is a copy of the included example.conf-tmpl file that shows a basicconfiguration for this plugin.

input {    google_pubsub {        # Your GCP project id (name)        project_id => "my-project-1234"        # The topic name below is currently hard-coded in the plugin. You        # must first create this topic by hand and ensure you are exporting        # logging to this pubsub topic.        topic => "logstash-input-dev"        # The subscription name is customizeable. The plugin will attempt to        # create the subscription (but use the hard-coded topic name above).        subscription => "logstash-sub"        # If you are running logstash within GCE, it will use        # Application Default Credentials and use GCE's metadata        # service to fetch tokens.  However, if you are running logstash        # outside of GCE, you will need to specify the service account's        # JSON key file below.        #json_key_file => "/home/erjohnso/pkey.json"        # Should the plugin attempt to create the subscription on startup?        # This is not recommended for security reasons but may be useful in        # some cases.        #create_subscription => false    }}output { stdout { codec => rubydebug } }

Metadata and Attributes

The original Pub/Sub message is preserved in the special Logstash[@metadata][pubsub_message] field so you can fetch:

  • Message attributes
  • The origiginal base64 data
  • Pub/Sub message ID for de-duplication
  • Publish time

You MUST extract any fields you want in a filter prior to the data being sentto an output because Logstash deletes @metadata fields otherwise.

See the PubsubMessagedocumentationfor a full description of the fields.

Example to get the message ID:

input {google_pubsub {...}}filter {  mutate {    add_field => { "messageId" => "%{[@metadata][pubsub_message][messageId]}" }  }}output {...}

Google_pubsub Input Configuration Options

This plugin supports the following configuration options plus the Common Options described later.

Setting Input type Required

json_key_file

a valid filesystem path

No

max_messages

number

Yes

project_id

string

Yes

subscription

string

Yes

topic

string

Yes

include_metadata

boolean

No

create_subscription

boolean

No

Also see Common Options for a list of options supported by allinput plugins.

 

json_key_file

  • Value type is path
  • There is no default value for this setting.

If logstash is running within Google Compute Engine, the plugin will useGCE’s Application Default Credentials. Outside of GCE, you will need tospecify a Service Account JSON key file.

max_messages

  • This is a required setting.
  • Value type is number
  • Default value is 5

The maximum number of messages returned per request.The Pub/Sub system may return fewer than the number specified.

project_id

  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

Google Cloud Project ID (name, not number).

subscription

  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

topic

  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

Google Cloud Pub/Sub Topic and Subscription.Note that the topic must be created manually with Cloud Loggingpre-configured export to PubSub configured to use the defined topic.The subscription will be created automatically by the plugin.

include_metadata

  • Value type is boolean
  • Default value is false.

If set true, will include the full message data in the [@metadata][pubsub_message] field.

create_subscription

Note

Added in 1.2.0.

  • Value type is boolean
  • Default value is false.

If true, the plugin will try to create the subscription before publishing.Note: this requires additional permissions to be granted to the client and is notrecommended for most use-cases.

Common Options

The following configuration options are supported by all input plugins:

Setting Input type Required

add_field

hash

No

codec

codec

No

enable_metric

boolean

No

id

string

No

tags

array

No

type

string

No

Details

 

add_field

  • Value type is hash
  • Default value is {}

Add a field to an event

codec

  • Value type is codec
  • Default value is "plain"

The codec used for input data. Input codecs are a convenient method for decoding your data before it enters the input, without needing a separate filter in your Logstash pipeline.

enable_metric

  • Value type is boolean
  • Default value is true

Disable or enable metric logging for this specific plugin instanceby default we record all the metrics we can, but you can disable metrics collectionfor a specific plugin.

id

  • Value type is string
  • There is no default value for this setting.

Add a unique ID to the plugin configuration. If no ID is specified, Logstash will generate one.It is strongly recommended to set this ID in your configuration. This is particularly usefulwhen you have two or more plugins of the same type, for example, if you have 2 google_pubsub inputs.Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.

input {  google_pubsub {    id => "my_plugin_id"  }}

tags

  • Value type is array
  • There is no default value for this setting.

Add any number of arbitrary tags to your event.

This can help with processing later.

type

  • Value type is string
  • There is no default value for this setting.

Add a type field to all events handled by this input.

Types are used mainly for filter activation.

The type is stored as part of the event itself, so you canalso use the type to search for it in Kibana.

If you try to set a type on an event that already has one (forexample when you send an event from a shipper to an indexer) thena new input will not override the existing type. A type set atthe shipper stays with that event for its life evenwhen sent to another Logstash server.