Grafana Alloy

Grafana Alloy is an observability data pipeline for OpenTelemetry (OTel), Prometheus, Pyroscope, Loki, and many other metrics, logs, traces, and profiling tools. You can integrate GreptimeDB as a data sink for Alloy.

Prometheus Remote Write

Configure GreptimeDB as remote write target:

prometheus.remote_write "greptimedb" {
    endpoint {
        url = "${GREPTIME_SCHEME:=http}://${GREPTIME_HOST:=greptimedb}:${GREPTIME_PORT:=4000}/v1/prometheus/write?db=${GREPTIME_DB:=public}"

        basic_auth {
            username = "${GREPTIME_USERNAME}"
            password = "${GREPTIME_PASSWORD}"
        }
    }
}

• GREPTIME_HOST: GreptimeDB host address, e.g., localhost.
• GREPTIME_DB: GreptimeDB database name, default is public.
• GREPTIME_USERNAME and GREPTIME_PASSWORD: The authentication credentials for GreptimeDB.

For details on the data model transformation from Prometheus to GreptimeDB, refer to the Data Model section in the Prometheus Remote Write guide.

OpenTelemetry

GreptimeDB can also be configured as OpenTelemetry collector.

Metrics

otelcol.exporter.otlphttp "greptimedb" {
  client {
    endpoint = "${GREPTIME_SCHEME:=http}://${GREPTIME_HOST:=greptimedb}:${GREPTIME_PORT:=4000}/v1/otlp/"
    headers  = {
      "X-Greptime-DB-Name" = "${GREPTIME_DB:=public}",
    }
    auth     = otelcol.auth.basic.credentials.handler
  }
}

otelcol.auth.basic "credentials" {
  username = "${GREPTIME_USERNAME}"
  password = "${GREPTIME_PASSWORD}"
}

• GREPTIME_HOST: GreptimeDB host address, e.g., localhost.
• GREPTIME_DB: GreptimeDB database name, default is public.
• GREPTIME_USERNAME and GREPTIME_PASSWORD: The authentication credentials for GreptimeDB.

For details on the metrics data model transformation from OpenTelemetry to GreptimeDB, refer to the Data Model section in the OpenTelemetry guide.

Logs

This example sends logs to GreptimeDB through an OpenTelemetry pipeline. For production log pipelines, add an explicit batch processor before the exporter. See the Batching section for details.

loki.source.file "greptime" {
  targets = [
    {__path__ = "/tmp/foo.txt"},
  ]
  forward_to = [otelcol.receiver.loki.greptime.receiver]
}

otelcol.receiver.loki "greptime" {
  output {
    logs = [otelcol.processor.batch.greptimedb_logs.input]
  }
}

otelcol.processor.batch "greptimedb_logs" {
  send_batch_size     = 5000
  send_batch_max_size = 10000
  timeout             = "1s"

  output {
    logs = [otelcol.exporter.otlphttp.greptimedb_logs.input]
  }
}

otelcol.auth.basic "credentials" {
  username = "${GREPTIME_USERNAME}"
  password = "${GREPTIME_PASSWORD}"
}

otelcol.exporter.otlphttp "greptimedb_logs" {
  client {
    endpoint = "${GREPTIME_SCHEME:=http}://${GREPTIME_HOST:=greptimedb}:${GREPTIME_PORT:=4000}/v1/otlp/"
    headers = {
      "X-Greptime-DB-Name"          = "${GREPTIME_DB:=public}",
      "X-Greptime-Log-Table-Name"   = "${GREPTIME_LOG_TABLE_NAME:=demo_logs}",
      "X-Greptime-Log-Extract-Keys" = "filename,log.file.name,loki.attribute.labels",
    }
    auth = otelcol.auth.basic.credentials.handler
  }

  sending_queue {
    queue_size    = 10000
    num_consumers = 10
  }
}

• GREPTIME_HOST: GreptimeDB host address, such as localhost.
• GREPTIME_DB: GreptimeDB database name, default is public.
• GREPTIME_LOG_TABLE_NAME: Target log table name, default is demo_logs.
• GREPTIME_USERNAME and GREPTIME_PASSWORD: The authentication credentials for GreptimeDB.
• X-Greptime-Log-Extract-Keys: Keys extracted from OTLP log attributes. See the OTLP/HTTP API documentation for details.

For details on the log data model transformation from OpenTelemetry to GreptimeDB, refer to the Data Model section in the OpenTelemetry guide.

Loki

GreptimeDB also supports the Loki push protocol for logs. If your Alloy pipeline is already built with Loki components, we recommend using the native Loki ingestion path first. See the Loki guide for the Loki protocol details and data model mapping.

Logs

This example uses only Loki components to read, process, and send logs to GreptimeDB through the Loki push API:

loki.source.file "greptime" {
  targets = [
    {__path__ = "/tmp/foo.txt"},
  ]
  forward_to = [loki.process.greptime.receiver]
}

loki.process "greptime" {
  forward_to = [loki.write.greptimedb.receiver]

  stage.static_labels {
    values = {
      job  = "greptime",
      from = "alloy",
    }
  }
}

loki.write "greptimedb" {
  endpoint {
    url = "${GREPTIME_SCHEME:=http}://${GREPTIME_HOST:=greptimedb}:${GREPTIME_PORT:=4000}/v1/loki/api/v1/push"
    headers = {
      "X-Greptime-DB-Name"        = "${GREPTIME_DB:=public}",
      "X-Greptime-Log-Table-Name" = "${GREPTIME_LOG_TABLE_NAME:=loki_demo_logs}",
    }

    basic_auth {
      username = "${GREPTIME_USERNAME}"
      password = "${GREPTIME_PASSWORD}"
    }
  }
}

• GREPTIME_HOST: GreptimeDB host address, such as localhost.
• GREPTIME_DB: GreptimeDB database name, default is public.
• GREPTIME_LOG_TABLE_NAME: Target log table name, default is loki_demo_logs.
• GREPTIME_USERNAME and GREPTIME_PASSWORD: The authentication credentials for GreptimeDB.

This configuration tails /tmp/foo.txt, adds two static labels, and sends the logs directly to GreptimeDB with loki.write.

Batching

otelcol.exporter.otlphttp does not enable batching by default. When Alloy reads a burst of logs, such as a large backlog from files or Docker containers, the exporter queue can fill before enough records are grouped together, which leads to errors like sending queue is full.

Based on the behavior reported in production testing, enabling the exporter's internal sending_queue.batch block alone may still be insufficient for bursty log workloads. Putting otelcol.processor.batch in front of the exporter is a more reliable pattern for logs because the exporter receives larger bundled batches instead of many individual log records.

If you use OTLP/HTTP for logs, we recommend this order:

1. loki.source.*
2. otelcol.receiver.loki
3. otelcol.processor.batch
4. otelcol.exporter.otlphttp

If your pipeline is already Loki-native and you do not need OpenTelemetry processing, prefer loki.write and the Loki push protocol instead.

NOTE

Refer to the official Grafana Alloy documentation for the latest component behavior and tuning guidance, especially for loki.write, otelcol.processor.batch, and otelcol.exporter.otlphttp.