MQTT input

Use the MQTT input to read data transmitted using lightweight messaging protocol for small and mobile devices, optimized for high-latency or unreliable networks.

This input connects to the MQTT broker, subscribes to selected topics and parses data into common message lines. Everything happens before line filtering, multiline, and JSON decoding, so this input can be used in combination with those settings.

Example configuration:

filebeat.inputs:
- type: mqtt
  hosts: 
    - tcp://broker:1883
    - ssl://secure_broker:8883
  topics: 
    - sample_topic

hosts are required.

paths are required.

All other settings are optional.

Configuration options

The mqtt input supports the following configuration options plus the Common options described later.

hosts

A list of MQTT brokers to connect to.

topics

A list of topics to subscribe to and read from.

qos

An agreement level between the sender of a message and the receiver of a message that defines the guarantee of delivery.

There are 3 QoS levels in MQTT:

  • At most once (0),
  • At least once (1),
  • Exactly once (2).

client_id

A unique identifier of each MQTT client connecting to a MQTT broker.

username

A client username used for authentication provided on the application level by the MQTT protocol.

password

A client password used for authentication provided on the application level by the MQTT protocol.

ssl

Configuration options for SSL parameters like the certificate, key and the certificate authorities to use.

See SSL for more information.

Common options

The following configuration options are supported by all inputs.

enabled

Use the enabled option to enable and disable inputs. By default, enabled is set to true.

tags

A list of tags that Filebeat includes in the tags field of each published event. Tags make it easy to select specific events in Kibana or apply conditional filtering in Logstash. These tags will be appended to the list of tags specified in the general configuration.

Example:

filebeat.inputs:
- type: mqtt
  . . .
  tags: ["json"]
fields

Optional fields that you can specify to add additional information to the output. For example, you might add fields that you can use for filtering log data. Fields can be scalar values, arrays, dictionaries, or any nested combination of these. By default, the fields that you specify here will be grouped under a fields sub-dictionary in the output document. To store the custom fields as top-level fields, set the fields_under_root option to true. If a duplicate field is declared in the general configuration, then its value will be overwritten by the value declared here.

filebeat.inputs:
- type: mqtt
  . . .
  fields:
    app_id: query_engine_12
fields_under_root

If this option is set to true, the custom fields are stored as top-level fields in the output document instead of being grouped under a fields sub-dictionary. If the custom field names conflict with other field names added by Filebeat, then the custom fields overwrite the other fields.

processors

A list of processors to apply to the input data.

See Processors for information about specifying processors in your config.

pipeline

The Ingest Node pipeline ID to set for the events generated by this input.

The pipeline ID can also be configured in the Elasticsearch output, but this option usually results in simpler configuration files. If the pipeline is configured both in the input and output, the option from the input is used.

keep_null

If this option is set to true, fields with null values will be published in the output document. By default, keep_null is set to false.

index

If present, this formatted string overrides the index for events from this input (for elasticsearch outputs), or sets the raw_index field of the event’s metadata (for other outputs). This string can only refer to the agent name and version and the event timestamp; for access to dynamic fields, use output.elasticsearch.index or a processor.

Example value: "%{[agent.name]}-myindex-%{+yyyy.MM.dd}" might expand to "filebeat-myindex-2019.11.01".