6.3. Working with Logs #

This section describes the steps required to manage logs.

6.3.1. Adding and Configuring the filelog Receiver #

The filelog receiver is an open component of OpenTelemetry that is used for collecting logs from the DBMS instance. Detailed information about this receiver can be found here.

The filelog receiver should be added to the receivers section and configured.

The receiver configuration depends on the database instance setup and the log format used (see the logging_collector and log_destination parameters). The collector supports log collection in the CSV and JSON formats.

Regardless of the log format, the path to the log directory and the template for log file names need to be specified.

An example of setting up a receiver for collecting logs in the JSON format:

receivers:
  filelog:
    include: [ /var/log/postgresql/*.json ]
    start_at: end
    retry_on_failure:
      enabled: true
      initial_interval: 1s
      max_interval: 30s
      max_elapsed_time: 5m
    operators:
      - type: csv_parser
        parse_ints: true
        timestamp:
          parse_from: attributes.timestamp
          layout_type: strptime
          layout: '%Y-%m-%d %H:%M:%S.%L %Z'
      - type: remove
        field: attributes.timestamp

An example of setting up a receiver for collecting logs in the CVS format:

receivers:
  filelog:
    include: [ /var/log/postgresql/*.csv ]
    start_at: end
    retry_on_failure:
      enabled: true
      initial_interval: 1s
      max_interval: 30s
      max_elapsed_time: 5m
    multiline:
      line_start_pattern: ^[0-9]{4}-[0-9]{2}-[0-9]{2}
    operators:
      - type: csv_parser
        header: timestamp,user,dbname,pid,connection_from,session_id,line_num,ps,session_start,vxid,txid,error_severity,state_code,message,detail,hint,internal_query,internal_position,context,statement,cursor_position,func_name,application_name,backend_type,leader_pid,query_id
        timestamp:
          parse_from: attributes.timestamp
          layout_type: strptime
          layout: '%Y-%m-%d %H:%M:%S.%L %Z'
      - type: remove
        field: attributes.timestamp

Note

CSV configuration requires specifying more parameters than other formats, as it has to adapt to CSV logging specifics.

A detailed description of configuration parameters with examples can be found in the /usr/share/doc/pgpro-otel-collector/examples directory.

6.3.2. Adding and Configuring the attributes and resource Processors #

The attributes and resource processors are open components of OpenTelemetry.

The processor configuration also depends on the database instance setup and the log format used (see the logging_collector and log_destination parameters).

The resource processor needs to be configured when sending logs to Elastic. Regardless of the log format, the service.name and service.instance.id attributes need to be specified.

An example of setting up processors for collecting logs in the JSON format:

processors:
  attributes/convert:
    actions:
      - key: query_id
        action: convert
        converted_type: string
  resource:
    attributes:
      - key: service.name
        action: upsert
        value: postgresql
      - key: service.instance.id
        action: upsert
        value: 1.2.3.4:5432

An example of setting up processors for collecting logs in the CSV format:

processors:
  attributes/convert:
    actions:
      - key: pid
        action: convert
        converted_type: int
      - key: line_num
        action: convert
        converted_type: int
      - key: txid
        action: convert
        converted_type: int
      key: remote_port
        action: convert
        converted_type: int
      - key: cursor_position
        action: convert
        converted_type: int
      - key: internal_position
        action: convert
        converted_type: int
      - key: leader_pid
        action: convert
        converted_type: int
  resource:
    attributes:
      - key: service.name
        action: upsert
        value: postgresql
      - key: service.instance.id
        action: upsert
        value: 1.2.3.4:5432

6.3.3. Adding and Configuring the otlphttp Exporter #

The otlphttp exporter is an open component of OpenTelemetry and is used for exporting collected logs to an OTLP-compatible storage or monitoring system that has to be predeployed and accessible. Read here to learn more.

To configure the otlphttp exporter, it is sufficient to specify the address of the target system where data should be sent:

exporters:
  otlphttp:
    endpoint: https://otlp.example.org

6.3.4. Setting up a Pipeline #

Once receivers, processors, and exporters are added and configured, they need to be combined into a pipeline. The pipeline is configured in the service section. The pipeline contents depend altogether on the previously added components (there is no default configuration).

Below is the example of how to set up a pipeline for log management. The data is collected by the filelog receiver, processed by the resource and attributes processors and exported by the otlphttp exporter.

Thus, all the components used in the pipeline should also be added in the configuration file and set up.

service:
  extensions: []
  pipelines:
    logs:
      receivers:
        - filelog
      processors:
        - resource
        - attributes/convert
      exporters:
        - otlphttp