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.

• OpenTelemetry Exporters
• OpenTelemetry HTTP spec
• HTTP metrics spec

Usage

Add the OpenTelemetry middleware dependency with Go modules:

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

Note

Echo v4 applications use github.com/labstack/echo-otel/v4. github.com/labstack/echo-opentelemetry is the deprecated previous name of this module; see Migrating from echo-opentelemetry.

Import the middleware and the OpenTelemetry trace API:

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

Register it with full configuration:

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