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Documentation Grafana Agent Flow mode Reference Components reference loki.source.gcplog

loki.source.gcplog

loki.source.gcplog retrieves logs from cloud resources such as GCS buckets, load balancers, or Kubernetes clusters running on GCP by making use of Pub/Sub subscriptions.

The component uses either the ‘push’ or ‘pull’ strategy to retrieve log entries and forward them to the list of receivers in forward_to.

Multiple loki.source.gcplog components can be specified by giving them different labels.

Usage

Alloy Copy

loki.source.gcplog "LABEL" {
  pull {
    project_id   = "PROJECT_ID"
    subscription = "SUB_ID"
  }

  forward_to = RECEIVER_LIST
}

Arguments

loki.source.gcplog supports the following arguments:

Blocks

The following blocks are supported inside the definition of loki.source.gcplog:

The pull and push inner blocks are mutually exclusive; a component must contain exactly one of the two in its definition. The http and grpc block are just used when the push block is configured.

pull block

The pull block defines which GCP project ID and subscription to read log entries from.

The following arguments can be used to configure the pull block. Any omitted fields take their default values.

To make use of the pull strategy, the GCP project must have been configured to forward its cloud resource logs onto a Pub/Sub topic for loki.source.gcplog to consume.

Typically, the host system also needs to have its GCP credentials configured. One way to do it is to point the GOOGLE_APPLICATION_CREDENTIALS environment variable to the location of a credential configuration JSON file or a service account key.

push block

The push block defines the configuration of the server that receives push requests from GCP’s Pub/Sub servers.

The following arguments can be used to configure the push block. Any omitted fields take their default values.

The server listens for POST requests from GCP’s Push subscriptions on HOST:PORT/gcp/api/v1/push.

By default, for both strategies the component assigns the log entry timestamp as the time it was processed, except if use_incoming_timestamp is set to true.

The labels map is applied to every entry that passes through the component.

http

grpc

Exported fields

loki.source.gcplog does not export any fields.

Component health

loki.source.gcplog is only reported as unhealthy if given an invalid configuration.

Debug information

loki.source.gcplog exposes some debug information per gcplog listener:

• The configured strategy.
• Their label set.
• When using a push strategy, the listen address.

Debug metrics

When using the pull strategy, the component exposes the following debug metrics:

• loki_source_gcplog_pull_entries_total (counter): Number of entries received by the gcplog target.
• loki_source_gcplog_pull_parsing_errors_total (counter): Total number of parsing errors while receiving gcplog messages.
• loki_source_gcplog_pull_last_success_scrape (gauge): Timestamp of target’s last successful poll.

When using the push strategy, the component exposes the following debug metrics:

• loki_source_gcplog_push_entries_total (counter): Number of entries received by the gcplog target.
• loki_source_gcplog_push_entries_total (counter): Number of parsing errors while receiving gcplog messages.

Example

This example listens for GCP Pub/Sub PushRequests on 0.0.0.0:8080 and forwards them to a loki.write component.

Alloy Copy

loki.source.gcplog "local" {
  push {}

  forward_to = [loki.write.local.receiver]
}

loki.write "local" {
  endpoint {
    url = "loki:3100/api/v1/push"
  }
}

On the other hand, if we need the server to listen on 0.0.0.0:4040, and forwards them to a loki.write component.

Alloy Copy

loki.source.gcplog "local" {
  push {
    http {
        listen_port = 4040
    }
  }

  forward_to = [loki.write.local.receiver]
}

loki.write "local" {
  endpoint {
    url = "loki:3100/api/v1/push"
  }
}

Compatible components

loki.source.gcplog can accept arguments from the following components:

• Components that export Loki LogsReceiver