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Documentation Grafana Alloy Reference Configuration blocks logging

logging block

logging is an optional configuration block used to customize how Alloy produces log messages. logging is specified without a label and can only be provided once per configuration file.

Example

alloy Copy

logging {
  level  = "info"
  format = "logfmt"
}

Arguments

The following arguments are supported:

Log level

The following strings are recognized as valid log levels:

• "error": Only write logs at the error level.
• "warn": Only write logs at the warn level or above.
• "info": Only write logs at info level or above.
• "debug": Write all logs, including debug level logs.

Log format

The following strings are recognized as valid log line formats:

• "logfmt": Write logs as logfmt lines.
• "json": Write logs as JSON objects.

Log receivers

The write_to argument allows Alloy to tee its log entries to one or more loki.* component log receivers in addition to the default location. This, for example can be the export of a loki.write component to ship log entries directly to Loki, or a loki.relabel component to add a certain label first.

Log location

Alloy writes all logs to stderr.

When running Alloy as a systemd service, view logs written to stderr through journald.

When running Alloy as a container, view logs written to stderr through docker logs or kubectl logs, depending on whether Docker or Kubernetes was used for deploying Alloy.

When running Alloy as a Windows service, logs are instead written as event logs. You can view the logs through Event Viewer.

In other cases, redirect stderr of the Alloy process to a file for logs to persist on disk.