Crate otlp_stdout_client

otlp-stdout-client

otlp-stdout-client is a Rust library that provides an OpenTelemetry exporter designed for serverless environments, particularly AWS Lambda functions. This crate is part of the serverless-otlp-forwarder project, which provides a comprehensive solution for OpenTelemetry telemetry collection in AWS Lambda environments.

This exporter implements the opentelemetry_http::HttpClient interface and can be used in an OpenTelemetry OTLP pipeline to send OTLP data (both JSON and Protobuf formats) to stdout. This allows the data to be easily ingested and forwarded to an OTLP collector.

Key Features

• Implements opentelemetry_http::HttpClient for use in OTLP pipelines
• Exports OpenTelemetry data to stdout in a structured format
• Designed for serverless environments, especially AWS Lambda
• Configurable through environment variables
• Optional GZIP compression of payloads
• Supports both JSON and Protobuf payloads

Usage

This library can be integrated into OpenTelemetry OTLP pipelines to redirect telemetry data to stdout. It’s particularly useful in serverless environments where direct network access to a collector might not be available or desired.

use otlp_stdout_client::StdoutClient;
use opentelemetry_sdk::trace::SdkTracerProvider;
use opentelemetry_otlp::{WithExportConfig, WithHttpConfig};
use opentelemetry::trace::Tracer;
use opentelemetry::global;

fn init_tracer_provider() -> Result<SdkTracerProvider, Box<dyn std::error::Error>> {
    let exporter = opentelemetry_otlp::SpanExporter::builder()
        .with_http()
        .with_http_client(StdoutClient::default())
        .build()?;
     
    let tracer_provider = opentelemetry_sdk::trace::SdkTracerProvider::builder()
        .with_simple_exporter(exporter)
        .build();

    Ok(tracer_provider)
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let tracer_provider = init_tracer_provider()?;
    global::set_tracer_provider(tracer_provider.clone());
     
    let tracer = global::tracer("my_tracer");
     
    // Use the tracer for instrumenting your code
    // For example:
    tracer.in_span("example_span", |_cx| {
        // Your code here
    });

    Ok(())
}

Configuration

The exporter can be configured using the following standard OTEL environment variables:

• OTEL_EXPORTER_OTLP_PROTOCOL: Specifies the protocol to use for the OTLP exporter. Valid values are:

  • “http/json” (default): Uses HTTP with JSON payload
  • “http/protobuf”: Uses HTTP with Protobuf payload

• OTEL_EXPORTER_OTLP_ENDPOINT: Sets the endpoint for the OTLP exporter. Specify the endpoint of your OTLP collector.

• OTEL_EXPORTER_OTLP_HEADERS: Sets additional headers for the OTLP exporter. Format: “key1=value1,key2=value2”

• OTEL_EXPORTER_OTLP_COMPRESSION: Specifies the compression algorithm to use. Valid values are:

  • “gzip”: Compresses the payload using GZIP
  • If not set or any other value, no compression is applied

For more detailed information on usage and configuration, please refer to the README.md file.

Structs

LogRecord

StdoutClient

Constants

CONTENT_ENCODING_HEADER

CONTENT_TYPE_HEADER

CONTENT_TYPE_JSON

CONTENT_TYPE_PROTOBUF

ENCODING_GZIP

KEY_BASE64

KEY_ENDPOINT

KEY_HEADERS

KEY_METHOD

KEY_PAYLOAD

KEY_SOURCE

OTEL_VERSION_PREFIX