Rustic - A minimalistic library in Go for HTTP Client and tracing constructs

Yet another HTTP Client in go with very simple yet essential features

Features of HTTPClient

• http client with type safety
• Different http configurations support - Timeout, Headers, QueryParams, FormParams, MultipartFormParams, CircuitBreaker
• Supports GET, POST, POSTMultiPartFormData, POSTFormData, PUT
  • DELETE, PATCH
• Add metrics either via open telemetry or prometheus metrics
• Add support for retries, it should have either default/custom or without any retrier

Features of Tracing constructs

• supports opentelemetry - stdOut and OTLP Http exporter
• tracing middleware for echo v3 and v4

NOTE: For circuit breaker https://github.com/sony/gobreaker is used.

Usage

go get github.com/rag594/rustic

How to use it

HTTP Client

// UserPost represents the post/blog by a specific user 
type UserPost struct {
	UserId int    `json:"userId"`
	Id     int    `json:"id"`
	Title  string `json:"title"`
	Body   string `json:"body"`
}

Initialise tracer for HTTP client

shutdown := rusticTracer.InitTracer("microserviceA", "dev", rusticTracer.StdOutExporter())
defer shutdown()

// configure your http client
client := httpClient.NewHTTPClient(httpClient.WithTraceEnabled(true))
url := "https://jsonplaceholder.typicode.com/posts"

// define your query params
params := url2.Values{}
params.Add("userId", "1")

// configure your circuit breaker(currently only sony circuit breaker is supported)
st := &gobreaker.Settings{}
st.Name = "HTTP GET"

st.ReadyToTrip = func(counts gobreaker.Counts) bool {
        failureRatio := float64(counts.TotalFailures) / float64(counts.Requests)
        return counts.Requests >= 3 && failureRatio >= 0.6
}

cb := gobreaker.NewCircuitBreaker[any](*st)

Trigger HTTP client

post, err := rustic.GET[[]UserPost](context.Background(),
        url,
        rustic.WithQueryParams(params),
        rustic.WithHttpClient(client),
        rustic.WithTimeout(time.Duration(1)*time.Second),
        rustic.WithCircuitBreaker(cb), 
			)
    if err != nil {
        fmt.Println(err)
    }

    fmt.Println(post)

Opentelementry Tracing

Using with Echo Framework

Initialise the trace with service name, environment and exporter()below is an OTLP exporter with configured telemetry backend. That's it, you have configured the traces

// you can try out with tracer.StdOutExporter() in your localhost
	shutdown := rusticTracer.InitTracer("userService", "dev", rusticTracer.OTLPExporter("localhost", "4318"))

	defer shutdown()
	e.Use(rusticTracer.Echov4TracerMiddleware("userService"))

You can run the sample under example/echoTraceMiddleware and observe the trace as below:

Important information wrt context

1. If you pass the context as nil, then context is set as Background
2. If you pass the timeout, new context is derived from parent context
3. If you wish to maintain context timeout at the parent level, do not pass timeout