Documentation Grafana Cloud Instrument and send data Grafana Alloy Reference Components otelcol otelcol.exporter.loki

otelcol.exporter.loki

otelcol.exporter.loki accepts OTLP-formatted logs from other otelcol components, converts them to Loki-formatted log entries, and forwards them to loki components.

The attributes of the OTLP log are not converted to Loki attributes by default. To convert them, the OTLP log should contain special “hint” attributes:

• To convert OTLP resource attributes to Loki labels, use the loki.resource.labels hint attribute.
• To convert OTLP log attributes to Loki labels, use the loki.attribute.labels hint attribute.

Labels will be translated to a Prometheus format, which is more constrained than the OTLP format. For examples on label translation, see the Converting OTLP attributes to Loki labels section.

Multiple otelcol.exporter.loki components can be specified by giving them different labels.

Usage

alloy Copy

otelcol.exporter.loki "LABEL" {
  forward_to = [...]
}

Arguments

otelcol.exporter.loki supports the following arguments:

Exported fields

The following fields are exported and can be referenced by other components:

input accepts otelcol.Consumer data for logs. Other telemetry signals are ignored.

Logs sent to input are converted to Loki-compatible log entries and are forwarded to the forward_to argument in sequence.

Component health

otelcol.exporter.loki is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.exporter.loki does not expose any component-specific debug information.

Examples

Basic usage

This example accepts OTLP logs over gRPC, transforms them and forwards the converted log entries to loki.write:

alloy Copy

otelcol.receiver.otlp "default" {
  grpc {}

  output {
    logs = [otelcol.exporter.loki.default.input]
  }
}

otelcol.exporter.loki "default" {
  forward_to = [loki.write.local.receiver]
}

loki.write "local" {
  endpoint {
    url = "loki:3100"
  }
}

Converting OTLP attributes to Loki labels

The example below will convert the following attributes to Loki labels:

• The service.name and service.namespace OTLP resource attributes.
• The event.domain and event.name OTLP log attributes.

Labels will be translated to a Prometheus format. For example:

alloy Copy

otelcol.receiver.otlp "default" {
  grpc {}

  output {
    logs = [otelcol.processor.attributes.default.input]
  }
}

otelcol.processor.attributes "default" {
  action {
    key = "loki.attribute.labels"
    action = "insert"
    value = "event.domain, event.name"
  }

  action {
    key = "loki.resource.labels"
    action = "insert"
    value = "service.name, service.namespace"
  }

  output {
    logs = [otelcol.exporter.loki.default.input]
  }
}

otelcol.exporter.loki "default" {
  forward_to = [loki.write.local.receiver]
}

loki.write "local" {
  endpoint {
      url = "loki:3100"
  }
}

Compatible components

otelcol.exporter.loki can accept arguments from the following components:

• Components that export Loki LogsReceiver

otelcol.exporter.loki has exports that can be consumed by the following components:

• Components that consume OpenTelemetry otelcol.Consumer