OpenTelemetry

Echo OpenTelemetry is a middleware that provides OpenTelemetry instrumentation for HTTP requests.

OpenTelemetry is a set of open-source tools that provide instrumentation for cloud-native applications.

Usage

Add the OpenTelemetry middleware dependency with Go modules:

go get github.com/labstack/echo-otel/v5

Import the middleware and the OpenTelemetry trace API:

import (
  echootel "github.com/labstack/echo-otel/v5"
  "go.opentelemetry.io/otel/trace"
)

e.Use(echootel.NewMiddlewareWithConfig(echootel.Config{
  ServerName:     "my-server",
  TracerProvider: tp,

  //Skipper:             nil,
  //OnNextError:         nil,
  //OnExtractionError:   nil,
  //MeterProvider:       nil,
  //Propagators:         nil,
  //SpanStartOptions:    nil,
  //SpanStartAttributes: nil,
  //SpanEndAttributes:   nil,
  //MetricAttributes:    nil,
  //Metrics:             nil,
}))

For configuration options, see the Config struct.

Add the middleware in simplified form by providing only the server name:

e.Use(echootel.NewMiddleware("app.example.com"))

Add the middleware with configuration options:

e.Use(echootel.NewMiddlewareWithConfig(echootel.Config{
  TracerProvider: tp,
}))

Retrieve the tracer from the Echo context:

tracer, err := echo.ContextGet[trace.Tracer](c, echootel.TracerKey)

Example

The example exports spans to stdout, but you can use any exporter (OTLP, etc.). See the OpenTelemetry exporters documentation.

API reference

Config · github.com/labstack/echo-otel/[email protected]

Fields from package source
Field	Type	Description	Source
`ServerName`	`string`	ServerName is set as `server.address` and `server.port` span attributes. They are not added to metrics by default (Opt-In in the semantic conventions); add them with MetricAttributes if needed. Example: "api.example.com" or "example.com:8080". Without a port, `server.port` is not set. If known, this value must be set to the server’s canonical (primary) name. For example, in Apache this corresponds to the ServerName directive (https://httpd.apache.org/docs/2.4/mod/core.html#servername), and in NGINX to the server_name directive (http://nginx.org/en/docs/http/ngx_http_core_module.html#server_name). More generally, the primary server name is the host header value that maps to the HTTP server’s default virtual host. It must include the hostname, and if the server is accessed via a non-default port, the port must be appended using the standard ":port" suffix. If the primary server name is unknown, this field should be set to an empty string. In that case, Request.Host will be used to resolve the effective server name and port. Request.Host is chosen by the client.	L50
`Skipper`	`middleware.Skipper`	Skipper defines a function to skip middleware.	L53
`OnNextError`	`OnErrorFunc`	OnNextError is used to specify how errors returned from the next middleware / handler are handled.	L56
`OnExtractionError`	`OnErrorFunc`	OnExtractionError is used to specify how errors returned from request extraction are handled.	L59
`TracerProvider`	`oteltrace.TracerProvider`	TracerProvider allows overriding the default tracer provider.	L62
`MeterProvider`	`metric.MeterProvider`	MeterProvider allows overriding the default meter provider.	L65
`Propagators`	`propagation.TextMapPropagator`	Propagators allow overriding the default propagators.	L68
`SpanStartOptions`	`[]oteltrace.SpanStartOption`	SpanStartOptions configures an additional set of trace.SpanStartOptions, which are applied to each new span.	L71
`SpanStartAttributes`	`AttributesFunc`	SpanStartAttributes is used to extract additional attributes from the echo.Context and return them as a slice of attribute.KeyValue.	L75
`SpanEndAttributes`	`AttributesFunc`	SpanEndAttributes is used to extract additional attributes from the echo.Context and return them as a slice of attribute.KeyValue.	L79
`MetricAttributes`	`MetricAttributesFunc`	MetricAttributes is used to compose attributes just before Metrics.Record call.	L82
`Metrics`	`MetricsRecorder`	Metrics is used to record custom metrics instead of default.	L85

Functions from package source
Type	Source
`func NewMiddleware(serverName string) echo.MiddlewareFunc`	L105
`func NewMiddlewareWithConfig(config Config) echo.MiddlewareFunc`	L110