Performance considerations for Golang API in microservice architecture

// ./handlers/cache.go
package handlers

import (
    "net/http"
    "time"

    "github.com/go-cache/go-cache"
)

// Cache is an in-memory cache.
var Cache = cache.New(5*time.Minute, 10*time.Minute)

// CacheRequestHandler is a middleware that caches HTTP responses.
func CacheRequestHandler(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // Check if the response is already cached.
        if cachedResponse, found := Cache.Get(r.URL.Path); found {
            // If found, serve the cached response.
            w.Write(cachedResponse.([]byte))
            return
        }
        // If not found, call the next handler.
        next.ServeHTTP(w, r)
        // Cache the response for future requests.
        Cache.Set(r.URL.Path, w, cache.DefaultExpiration)
    })
}

// ./main.go
package main

import (
    "fmt"
    "net/http"

    "github.com/gorilla/mux"

    "./handlers"
)

func main() {
    r := mux.NewRouter()

    // Add middleware to cache static file responses.
    r.Use(handlers.CacheRequestHandler)
}

// ./handlers/trace.go
package handlers

import (
    "context"
    "fmt"
    "net/http"

    "github.com/opentracing/opentracing-go"
    "github.com/opentracing/opentracing-go/ext"
)

func TracesHandler(w http.ResponseWriter, r *http.Request) {
    // Create a new span for this request.
    span, ctx := opentracing.StartSpanFromContext(r.Context(), "traces")

    // Add some tags to the span.
    ext.HTTPMethod.Set(span, r.Method)
    ext.HTTPUrl.Set(span, r.RequestURI)

    // Simulate work being done.
    fmt.Fprintln(w, "Hello, traces!")

    // Finish the span.
    span.Finish()
}

// ./main.go
package main

import (
    "fmt"
    "net/http"

    "github.com/gorilla/mux"
    "github.com/opentracing/opentracing-go"
    "github.com/uber/jaeger-client-go"
    "github.com/uber/jaeger-client-go/config"
)

func main() {
    // Configure and initialize Jaeger tracer.
    cfg := &config.Configuration{
        ServiceName: "go-api",
    }
    tracer, closer, err := cfg.NewTracer()
    if err != nil {
        panic(err)
    }
    defer closer.Close()

    opentracing.SetGlobalTracer(tracer)

    r := mux.NewRouter()

    // Add route that uses tracing.
    r.HandleFunc("/traces", handlers.TracesHandler)
}