// This file is an example of integrating an external APM system (DataDog)

// which needs to be able to do some setup, wrap all handlers, and do teardown

// when RAIS is shutting down. Use of this plugin should be fairly

// straightforward, but you will have to add some configuration for DataDog.

//

// First, you must set up a DataDog agent. If you do this with compose,

// DD_API_KEY should be added to your .env, but you should be able to use our

// demo compose.yml file otherwise.

//

// Then, "DatadogAddress" must be added to your rais.toml or else

// RAIS_DATADOGADDRESS must be in your RAIS environment. This is shown in our

// demo compose.yml.

//

// If you want to set a custom service name, set "DatadogServiceName" or else

// expose RAIS_DatadogServiceName in your environment. The default service

// name is "RAIS/datadog".

//

// If you want instrumentation that goes deeper than request round-tripping,

// please be aware that RAIS does not currently support this.

package main

import (

"net/http"

"github.com/spf13/viper"

"github.com/uoregon-libraries/gopkg/logger"

httptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/net/http"

"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"

)

var l *logger.Logger

var serviceName string

// Disabled lets the plugin manager know not to add this plugin's functions to

// the global list unless sanity checks in Initialize() pass

var Disabled = true

// Initialize reads configuration and sets up the datadog agent

func Initialize() {

var ddaddr = viper.GetString("DatadogAddress")

viper.SetDefault("DatadogServiceName", "RAIS/datadog")

serviceName = viper.GetString("DatadogServiceName")

if ddaddr == "" {

l.Warnf("DatadogAddress must be configured, or RAIS_DATADOGADDRESS must be set in the environment **DataDog plugin is disabled**")

return

}

Disabled = false

l.Debugf("Connecting to datadog agent at %q", ddaddr)

tracer.Start(tracer.WithAgentAddr(ddaddr))

}

// WrapHandler takes all RAIS routes' handlers and puts the datadog

// instrumentation into them

func WrapHandler(pattern string, handler http.Handler) (http.Handler, error) {

return httptrace.WrapHandler(handler, serviceName, pattern), nil

}

// Teardown tells datadog to shut down the tracer gracefully

func Teardown() {

tracer.Stop()

}

// SetLogger is called by the RAIS server's plugin manager to let plugins use

// the central logger

func SetLogger(raisLogger *logger.Logger) {

l = raisLogger

}