Documentation Grafana Cloud Instrument and send data Grafana Alloy Reference Components otelcol otelcol.receiver.otlp

otelcol.receiver.otlp

otelcol.receiver.otlp accepts OTLP-formatted data over the network and forwards it to other otelcol.* components.

Multiple otelcol.receiver.otlp components can be specified by giving them different labels.

Usage

alloy Copy

otelcol.receiver.otlp "<LABEL>" {
  grpc { ... }
  http { ... }

  output {
    metrics = [...]
    logs    = [...]
    traces  = [...]
  }
}

Arguments

The otelcol.receiver.otlp component doesn’t support any arguments. You can configure this component with blocks.

Blocks

You can use the following blocks with otelcol.receiver.otlp:

The > symbol indicates deeper levels of nesting. For example, grpc > tls refers to a tls block defined inside a grpc block.

output

Required

The output block configures a set of components to forward resulting telemetry data to.

The following arguments are supported:

You must specify the output block, but all its arguments are optional. By default, telemetry data is dropped. Configure the metrics, logs, and traces arguments accordingly to send telemetry data to other components.

debug_metrics

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

disable_high_cardinality_metrics is the Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.

grpc

The grpc block configures the gRPC server used by the component. If the grpc block isn’t provided, a gRPC server isn’t started.

The following arguments are supported:

keepalive

The keepalive block configures keepalive settings for connections to a gRPC server.

keepalive doesn’t support any arguments and is configured fully through inner blocks.

enforcement_policy

The enforcement_policy block configures the keepalive enforcement policy for gRPC servers. The server will close connections from clients that violate the configured policy.

The following arguments are supported:

server_parameters

The server_parameters block controls keepalive and maximum age settings for gRPC servers.

The following arguments are supported:

tls

The tls block configures TLS settings used for a server. If the tls block isn’t provided, TLS won’t be used for connections to the server.

The following arguments are supported:

If reload_interval is set to "0s", the certificate never reloaded.

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

• ca_pem and ca_file
• cert_pem and cert_file
• key_pem and key_file

If cipher_suites is left blank, a safe default list is used. Refer to the Go Cipher Suites documentation for a list of supported cipher suites.

client_ca_file sets the ClientCA and ClientAuth to RequireAndVerifyClientCert in the TLSConfig. Refer to the Go TLS documentation for more information.

The curve_preferences argument determines the set of elliptic curves to prefer during a handshake in preference order. If not provided, a default list is used. The set of elliptic curves available are X25519, P521, P256, and P384.

http

The http block configures the HTTP server used by the component. If the http block isn’t specified, an HTTP server isn’t started.

The following arguments are supported:

To send telemetry signals to otelcol.receiver.otlp with HTTP/JSON, POST to:

• [endpoint][traces_url_path] for traces.
• [endpoint][metrics_url_path] for metrics.
• [endpoint][logs_url_path] for logs.

cors

The cors block configures CORS settings for an HTTP server.

The following arguments are supported:

The allowed_headers argument specifies which headers are acceptable from a CORS request. The following headers are always implicitly allowed:

• Accept
• Accept-Language
• Content-Type
• Content-Language

If allowed_headers includes "*", all headers are permitted.

Exported fields

otelcol.receiver.otlp doesn’t export any fields.

Component health

otelcol.receiver.otlp is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.receiver.otlp doesn’t expose any component-specific debug information.

Debug metrics

• otelcol_receiver_accepted_spans_total (counter): Number of spans successfully pushed into the pipeline.
• otelcol_receiver_refused_spans_total (counter): Number of spans that couldn’t be pushed into the pipeline.
• rpc_server_duration_milliseconds (histogram): Duration of RPC requests from a gRPC server.
• rpc_server_request_size_bytes (histogram): Measures size of RPC request messages (uncompressed).
• rpc_server_requests_per_rpc (histogram): Measures the number of messages received per RPC. Should be 1 for all non-streaming RPCs.
• rpc_server_response_size_bytes (histogram): Measures size of RPC response messages (uncompressed).
• rpc_server_responses_per_rpc (histogram): Measures the number of messages received per RPC. Should be 1 for all non-streaming RPCs.

Example

This example forwards received telemetry data through a batch processor before finally sending it to an OTLP-capable endpoint:

alloy Copy

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

  output {
    metrics = [otelcol.processor.batch.default.input]
    logs    = [otelcol.processor.batch.default.input]
    traces  = [otelcol.processor.batch.default.input]
  }
}

otelcol.processor.batch "default" {
  output {
    metrics = [otelcol.exporter.otlp.default.input]
    logs    = [otelcol.exporter.otlp.default.input]
    traces  = [otelcol.exporter.otlp.default.input]
  }
}

otelcol.exporter.otlp "default" {
  client {
    endpoint = sys.env("<OTLP_ENDPOINT>")
  }
}

Technical details

otelcol.receiver.otlp supports Gzip for compression.

Enable authentication

You can create a otelcol.reciever.otlp component that requires authentication for requests. This is useful for limiting who can push data to the server.

alloy Copy

otelcol.receiver.otlp "default" {
  http {
    auth = otelcol.auth.basic.creds.handler
  }
  grpc {
     auth = otelcol.auth.basic.creds.handler
  }

  output {
   ...
  }
}

otelcol.auth.basic "creds" {
    username = sys.env("<USERNAME>")
    password = sys.env("<PASSWORD>")
}

Compatible components

otelcol.receiver.otlp can accept arguments from the following components:

• Components that export OpenTelemetry otelcol.Consumer