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Documentation Grafana Agent Grafana Agent Flow Reference Components loki.write

loki.write

loki.write receives log entries from other loki components and sends them over the network using Loki’s logproto format.

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

Usage

river Copy

loki.write "LABEL" {
  endpoint {
    url = REMOTE_WRITE_URL
  }
}

Arguments

loki.write supports the following arguments:

Blocks

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

The > symbol indicates deeper levels of nesting. For example, endpoint > basic_auth refers to a basic_auth block defined inside an endpoint block.

endpoint block

The endpoint block describes a single location to send logs to. Multiple endpoint blocks can be provided to send logs to multiple locations.

The following arguments are supported:

At most one of the following can be provided:

• bearer_token argument.
• bearer_token_file argument.
• basic_auth block.
• authorization block.
• oauth2 block.

If no tenant_id is provided, the component assumes that the Loki instance at endpoint is running in single-tenant mode and no X-Scope-OrgID header is sent.

When multiple endpoint blocks are provided, the loki.write component creates a client for each. Received log entries are fanned-out to these clients in succession. That means that if one client is bottlenecked, it may impact the rest.

Endpoints can be named for easier identification in debug metrics by using the name argument. If the name argument isn’t provided, a name is generated based on a hash of the endpoint settings.

basic_auth block

password and password_file are mututally exclusive and only one can be provided inside of a basic_auth block.

authorization block

credential and credentials_file are mutually exclusive and only one can be provided inside of an authorization block.

oauth2 block

client_secret and client_secret_file are mututally exclusive and only one can be provided inside of an oauth2 block.

The oauth2 block may also contain its own separate tls_config sub-block.

tls_config block

When min_version is not provided, the minimum acceptable TLS version is inherited from Go’s default minimum version, TLS 1.2. If min_version is provided, it must be set to one of the following strings:

• "TLS10" (TLS 1.0)
• "TLS11" (TLS 1.1)
• "TLS12" (TLS 1.2)
• "TLS13" (TLS 1.3)

Exported fields

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

Component health

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

Debug information

loki.write does not expose any component-specific debug information.

Debug metrics

• loki_write_encoded_bytes_total (counter): Number of bytes encoded and ready to send.
• loki_write_sent_bytes_total (counter): Number of bytes sent.
• loki_write_dropped_bytes_total (counter): Number of bytes dropped because failed to be sent to the ingester after all retries.
• loki_write_sent_entries_total (counter): Number of log entries sent to the ingester.
• loki_write_dropped_entries_total (counter): Number of log entries dropped because they failed to be sent to the ingester after all retries.
• loki_write_request_duration_seconds (histogram): Duration of sent requests.
• loki_write_batch_retries_total (counter): Number of times batches have had to be retried.
• loki_write_stream_lag_seconds (gauge): Difference between current time and last batch timestamp for successful sends.

Example

This example creates a loki.write component that sends received entries to a local Loki instance:

river Copy

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