middleware Package

The twistingmercury/middleware package is a Go library that provides middleware for instrumenting and tracing incoming requests in a Gin web application. It uses twistingmercury/telemetry to collect and export telemetry data, including metrics and traces.

Features

• Middleware for instrumenting incoming requests in a gin-gonic/gin web application
• Integration with OpenTelemetry for collecting and exporting traces
• Automatic generation of request duration and count metrics
• Parsing of user agent and request headers for detailed telemetry data
• Customizable span naming and attribute generation
• Correlation of logs with trace and span information

Installation

go get github.com/twistingmercury/middleware

Usage

Please visit middleware-example for a comprehensive example of how to utilize both the middleware as well as the twistingmercury/telemetry package.

1. Initialize the logging package.
2. Initialize the metrics package.
3. Invoke metrics.Publish()
4. Initialize the tracing package.
5. Create a gin router and invoke gin.Use(middleware.PrometheusMetrics(..), middleware.OtelTracing(..), middleware.Logging(..)).

After that, you can define your routes and handlers as usual, and the middleware will automatically instrument and trace the incoming requests.

Telemetry Data

The Gin Middleware package generates the following telemetry data for the gin handlers (RESTful endpoints):

• Request duration metric: Measures the duration of each incoming request in milliseconds.
• Request count metric: Counts the number of incoming requests.
• Current request gauge metric: the current number of active requests.
• Request trace: Creates a trace for each incoming request, including span information.
• Detailed request information: Parses the user agent and request headers to include additional attributes in the telemetry data.

Telemetry collection

• Logs: Logs are written to stdout and correlated with traces if tracing middleware is used.
• Traces: Traces are sent to the configured exporter. In a production environment, you'd create gRPC exporter and send the data to an OTel collector.
• Metrics: Metrics are exposed by default over http on port 9090, i.e., http://[my-api]:9090/metrics

Contributing

Contributions to the twistingmercury/telemetry package are welcome! If you find any issues or have suggestions for improvements, please open an issue or submit a pull request on the GitHub repository.

License

The twistingmercury/middleware package is open-source and released under the MIT License.