Writing documentation

.github/workflows/ghcr-build-push.yml

@@ -5,6 +5,8 @@ on:
   push:
     branches:
       - main
+    paths-ignore:
+      - '**/README.md'
 
 env:
   REGISTRY: ghcr.io

README.md

@@ -1 +1,40 @@
 # geo-3d-otel
+
+[![golangci-lint](https://github.com/efumagal/geo-3d-otel/actions/workflows/golangci-lint.yml/badge.svg)](https://github.com/efumagal/geo-3d-otel/actions/workflows/golangci-lint.yml)
+
+## Introduction
+
+A simple HTTP client to serve APIs to calculate distance between 3D points.  
+Implemented using [Fiber](https://gofiber.io) and instrumented using [OpenTelemetry](https://opentelemetry.io).  
+
+When pushing on main the [Publish Docker image to GHCR](.github/workflows/ghcr-build-push.yml) is triggered this performs:  
+- Build the Docker image and push it to ghcr.io registry
+- Scan the docker image using [Snyk](https://snyk.io)
+- Update [kustomization.yaml](kustomize/kustomization.yaml) with the newly generated Docker image
+
+
+## Run
+
+```shell
+go run main.go
+```
+
+## Load test
+
+Pre-requiste [K6](https://k6.io)
+
+[Load test K6 script](k6-load/load_distance.js)
+
+```shell
+k6 run load_distance.js
+```
+
+## TO DOs
+
+- For a real app consider structuring the Go code using DDD Hexagonal pattern
+- Add unit tests and run them on PRs
+- Generate OpenAPI specs
+
+## Notes
+
+- 

k6-load/load_distance.js

@@ -0,0 +1,21 @@
+import http from "k6/http";
+import { check, group, sleep } from "k6";
+
+export const options = {
+  stages: [
+    { duration: "10s", target: 20 }, // simulate ramp-up of traffic from 1 to 20 users over 10s.
+    { duration: "20s", target: 100 }, // stay at 100 users for 20 seconds
+    { duration: "10s", target: 0 }, // ramp-down to 0 users
+  ],
+  thresholds: {
+    http_req_duration: ["p(99)<100"], // 99% of requests must completed below 100ms
+  },
+};
+
+const BASE_URL = "http://localhost:8080/distance";
+
+export default () => {
+  check(http.get(BASE_URL), {
+    "status is 200": (r) => r.status == 200,
+  });
+};

k6-load/load.js → k6-load/load_high_cpu.js

@@ -12,10 +12,10 @@ export const options = {
   },
 };
 
-const BASE_URL = "http://localhost:8080/cpu";
+const BASE_URL = "http://localhost:8080/action/cpu-load";
 
 export default () => {
-  check(http.get(BASE_URL), {
+  check(http.post(BASE_URL), {
     "status is 200": (r) => r.status == 200,
   });
 };

main.go

@@ -24,7 +24,6 @@ import (
 var tracer trace.Tracer
 
 func init() {
-	// Name the tracer after the package, or the service if you are in main
 	tracer = otel.Tracer("github.com/efumagal/geo-3d-otel")
 }
 
@@ -49,6 +48,7 @@ func main() {
 
 	app := fiber.New()
 
+	// Exclude instrumentation for /health 
 	app.Use(otelfiber.Middleware(otelfiber.WithNext(func(c *fiber.Ctx) bool {
 		return c.Path() == "/health"
 	})))
@@ -62,7 +62,8 @@ func main() {
 	})
 
 	app.Get("/hello", func(c *fiber.Ctx) error {
-		return c.SendStatus(http.StatusOK)
+		c.Set(fiber.HeaderContentType, fiber.MIMETextHTML)
+		return c.SendString("<h1>Hello, World !</h1>")
 	})
 
 	app.Get("/distance", func(c *fiber.Ctx) error {
@@ -78,11 +79,11 @@ func main() {
 		return c.JSON(map[string]any{"distance": distance})
 	})
 
-	app.Get("/cpu", func(c *fiber.Ctx) error {
+	app.Post("/action/cpu-load", func(c *fiber.Ctx) error {
 		// Create a child span
 		_, childSpan := tracer.Start(c.UserContext(), "distance_computation")
 
-		for i := 0; i < 1_000_000; i++ {
+		for i := 0; i < 1_000; i++ {
 			start := geo.NewCoord3d(randFloat(-90, 90), randFloat(-180, 180), randFloat(0, 10000))
 			end := geo.NewCoord3d(randFloat(-90, 90), randFloat(-180, 180), randFloat(0, 10000))
 			geo.Distance3D(start, end)