1 files changed, 147 insertions, 0 deletions
diff --git a/idvoc-2025/CommentsInteractor/main.go b/idvoc-2025/CommentsInteractor/main.go
new file mode 100644
index 0000000..9a19243
--- /dev/null
+++ b/idvoc-2025/CommentsInteractor/main.go
@@ -0,0 +1,147 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"github.com/gorilla/handlers"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+)
+
+func getenv(key, fallback string) string {
+	value := os.Getenv(key)
+	if len(value) == 0 {
+		return fallback
+	}
+	return value
+}
+
+type Comment struct {
+	Comment string `json:"comment"`
+}
+
+type EngineError struct {
+	Message        string `json:"message"`
+	AdditionalInfo string `json:"additionalInfo"`
+}
+
+var comments_engine_endpoint string
+var (
+	httpHits = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "comments_interactor_http_hits_total",
+		Help: "The total number of hits on a given route",
+	}, []string{"route", "method"})
+	commentsReceived = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "comments_interactor_comments_received_total",
+		Help: "The total number of comments received (successfully posted or not)",
+	})
+	commentsPosted = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "comments_interactor_comments_posted_total",
+		Help: "The total number of comments posted (successfully posted)",
+	})
+)
+
+func sendComment(w http.ResponseWriter, r *http.Request) {
+	commentsReceived.Inc()
+	if err := r.ParseForm(); err != nil {
+		fmt.Fprintf(w, "<h1>error</h1><p>ParseForm() err: %v</p>", err)
+		return
+	}
+	var comment Comment
+	comment.Comment = r.FormValue("comment")
+	if comment.Comment == "" {
+		fmt.Fprintf(w, "<h1>error</h1><p>Empty comment or malformed</p>")
+		return
+	}
+	obj, err := json.Marshal(comment)
+	if err != nil {
+		fmt.Fprintf(w, "<h1>error</h1><p>Empty comment or malformed</p>")
+		return
+	}
+	_, err = http.Post("http://"+comments_engine_endpoint+"/comment", "application/json", bytes.NewReader(obj))
+	if err == nil {
+		fmt.Fprintf(w, "<h1>Success !</h1><p>Comment posted</p>")
+		commentsPosted.Inc()
+	} else {
+		fmt.Fprintf(w, "<h1>Error</h1><p>Error while trying to send a comment: %s", err)
+	}
+}
+
+func showDashboard(w http.ResponseWriter, r *http.Request) {
+	io.WriteString(w, "<h1>Latest comments</h1>")
+	io.WriteString(w, "<p>")
+	resp, err := http.Get("http://" + comments_engine_endpoint + "/latest")
+	if err != nil {
+		log.Printf("Could not HTTP get on CommentsEngine: %s", err)
+		io.WriteString(w, fmt.Sprintf("Error contacting the backend, %s", err))
+	} else {
+		defer resp.Body.Close()
+		body, err := io.ReadAll(resp.Body)
+		var comments []string
+		err = json.Unmarshal(body, &comments)
+		if err != nil {
+			var engineError EngineError
+			err = json.Unmarshal(body, &engineError)
+			if err != nil {
+				log.Printf("CommentsEngine returned unexpected value: %s", err)
+				io.WriteString(w, fmt.Sprintf("CommentsEngine returned badly formated values, %s", err))
+			} else {
+				io.WriteString(w, fmt.Sprintf("CommentsEngine returned an error: %s<br/>Additional info: %s", engineError.Message, engineError.AdditionalInfo))
+			}
+		} else {
+			for i, comment := range comments {
+				io.WriteString(w, "<div><h3>comment "+strconv.Itoa(i)+"</h3><p>"+comment+"</p></div>")
+			}
+		}
+	}
+	io.WriteString(w, "</p>")
+	io.WriteString(w, "<h1>Send comment</h1>")
+	io.WriteString(w, "<form method=\"post\"><textarea name=\"comment\" autofocus=\"true\" placeholder=\"your comment ...\" rows=\"5\" cols=\"80\"></textarea><br/><input type=\"submit\" value=\"send comment\"></form>")
+}
+
+func getRoot(w http.ResponseWriter, r *http.Request) {
+	httpHits.With(prometheus.Labels{"route": "/", "method": r.Method}).Inc()
+	io.WriteString(w, "<!doctype html><html><head><title>CommentsInteractor</title></head><body>")
+	if r.Method == http.MethodPost {
+		sendComment(w, r)
+	}
+	showDashboard(w, r)
+	io.WriteString(w, "</body></html>")
+}
+
+func sendError(w http.ResponseWriter, err error, additionalInfo string) {
+	w.WriteHeader(http.StatusInternalServerError)
+	resp := make(map[string]string)
+	resp["message"] = fmt.Sprint(err)
+	resp["additionalInfo"] = additionalInfo
+	jsonResp, err := json.Marshal(resp)
+	if err != nil {
+		log.Fatalf("Error happened in JSON marshal. Err: %s", err)
+	}
+	w.Write(jsonResp)
+}
+
+func main() {
+	http.HandleFunc("/", getRoot)
+	prometheus.Unregister(prometheus.NewGoCollector())
+	http.Handle("/metrics", promhttp.Handler())
+
+	listeningHostPort := getenv("HOST", "127.0.0.1") + ":" + getenv("PORT", "9000")
+	comments_engine_endpoint = getenv("COMMENTS_ENGINE_ENDPOINT", "127.0.0.1:8000")
+	fmt.Printf("Starting the server on %s\n", listeningHostPort)
+	err := http.ListenAndServe(listeningHostPort, handlers.LoggingHandler(os.Stdout, http.DefaultServeMux))
+	if errors.Is(err, http.ErrServerClosed) {
+		fmt.Printf("server closed\n")
+	} else if err != nil {
+		fmt.Printf("error starting server: %s\n", err)
+		os.Exit(1)
+	}
+}