add healthcheck route

cmd/api/errors.go

@@ -0,0 +1,24 @@
+package main
+
+import "net/http"
+
+func (app *application) logError(r *http.Request, err error) {
+	app.slogger.Error(err.Error(), "request_method", r.Method, "request_url", r.URL.String())
+}
+
+func (app *application) errorResponse(w http.ResponseWriter, r *http.Request, status int, message any) {
+	env := envelope{"error": message}
+
+	err := app.writeJSON(w, status, env, nil)
+	if err != nil {
+		app.logError(r, err)
+		w.WriteHeader(500)
+	}
+}
+
+func (app *application) serverErrorResponse(w http.ResponseWriter, r *http.Request, err error) {
+	app.logError(r, err)
+
+	message := "the server encountered a problem and could not process your request"
+	app.errorResponse(w, r, http.StatusInternalServerError, message)
+}

cmd/api/healthcheck.go

@@ -0,0 +1,21 @@
+package main
+
+import "net/http"
+
+func (app *application) healthcheckHandler(w http.ResponseWriter, r *http.Request) {
+	env := envelope{
+		"status": "available",
+		"system_info": map[string]string{
+			"environment": app.cfg.env,
+			"version":     version,
+		},
+		"foundry": map[string]any{
+			"status":       app.foundryApp.Status,
+			"is_available": app.foundryApp.IsAvailable,
+		},
+	}
+	err := app.writeJSON(w, http.StatusOK, env, nil)
+	if err != nil {
+		app.serverErrorResponse(w, r, err)
+	}
+}

cmd/api/helpers.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type envelope map[string]any
+
+func (app *application) writeJSON(w http.ResponseWriter, status int, data envelope, headers http.Header) error {
+	js, err := json.MarshalIndent(data, "", "\t")
+	if err != nil {
+		return err
+	}
+	js = append(js, '\n')
+	for key, value := range headers {
+		w.Header()[key] = value
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	w.Write(js)
+
+	return nil
+}

cmd/api/main.go

@@ -44,6 +44,8 @@ type application struct {
 	logger     *log.Logger
 }
 
+var version = "0.1.0"
+
 func openDB(cfg config) (*sql.DB, error) {
 	db, err := sql.Open("sqlite3", cfg.db.dsn)
 	if err != nil {

cmd/api/router.go

@@ -11,6 +11,7 @@ func (app *application) routes() http.Handler {
 
 	router.HandlerFunc(http.MethodGet, "/", app.ShowText)
 	router.HandlerFunc(http.MethodGet, "/v1/when", app.WhenNextSession)
+	router.HandlerFunc(http.MethodGet, "/v1/healthcheck", app.healthcheckHandler)
 
 	return router
 }