For Mentor Review | output-and-error-handling | Prince Wilson

projects/output-and-error-handling/go.mod

@@ -0,0 +1,3 @@
+module github.com/CodeYourFuture/immersive-go-course/projects/output-and-error-handling
+
+go 1.22.4

projects/output-and-error-handling/main.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+)
+
+// Global constants
+const (
+	delayLimit = 5
+	url        = "http://localhost:8080"
+)
+
+func main() {
+
+	// Fetch weather updates
+	update, err := getWeatherUpdate(url)
+
+	// Handle errors and
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v ", err)
+		os.Exit(1)
+	} else if update == "" {
+		fmt.Fprint(os.Stderr, "error: no updates for today ")
+		os.Exit(1)
+	}
+
+	// Prints weather update
+	fmt.Fprintln(os.Stdout, update)
+
+}
+
+// Function to fetch weather updates
+func getWeatherUpdate(url string) (string, error) {
+
+	// HTTP GET request
+	resp, err := http.Get(url)
+
+	if err != nil {
+		return "", errors.New("sorry, could not get weather updates from " + url)
+	}
+
+	defer resp.Body.Close()
+
+	// Handle different HTTP status codes
+	switch resp.StatusCode {
+	case http.StatusOK:
+		return parseBody(resp)
+	case http.StatusTooManyRequests:
+		return "", retryServer(resp)
+	default:
+		return "", errors.New("an unexpected error occured, try later ")
+	}
+
+}
+
+// Function to parse response body
+func parseBody(request *http.Response) (string, error) {
+
+	body, err := io.ReadAll(request.Body)
+
+	if err != nil {
+		return "", errors.New("could not get the weather response ")
+	}
+
+	weatherUpdate := string(body)
+
+	return weatherUpdate, nil
+
+}
+
+// Function to handle retry logic based on Retry-After header
+func retryServer(request *http.Response) error {
+
+	const retryHeader = "Retry-After"
+	retryTime := request.Header.Get(retryHeader)
+
+	delay, err := strconv.Atoi(retryTime)
+
+	if err != nil {
+		return errors.New("service temporarily unavailable, retry later ")
+	}
+
+	// if delay within limit, retry after waiting
+	if delay <= delayLimit {
+		fmt.Fprintln(os.Stderr, "retrying, it might a take a while.....")
+		time.Sleep(time.Duration(delay) * time.Second)
+		getWeatherUpdate(url) //Retry fetching weather updates
+		return nil
+	}
+
+	return nil
+}