add postgres connection test

server/api/api.go

@@ -25,6 +25,9 @@ func Start() {
 
 	r.Route("/users", func(r chi.Router) {
 		r.Get("/", ListUsers)
+		r.Route("/{userID}", func(r chi.Router) {
+			r.Get("/", GetUser)
+		})
 	})
 
 	r.Route("/register", func(r chi.Router) {

server/api/db.go

@@ -10,13 +10,15 @@ import (
 	"github.com/jackc/pgx/v5"
 )
 
+var ErrUserNotFound = errors.New("db: user not found")
+
 func dbGetUser(id string) (*User, error) {
 	query := `SELECT id, name, password FROM users WHERE id = $1`
 	var user User
 	err := db.Pool.QueryRow(context.Background(), query, id).Scan(&user.ID, &user.Name, &user.Password)
 	if errors.Is(err, pgx.ErrNoRows) {
 		slog.Debug("db: user not found", "userid", id)
-		return nil, errors.New("user not found")
+		return nil, ErrUserNotFound
 	} else if err != nil {
 		slog.Error("db: failed to query user", "error", err)
 		return nil, fmt.Errorf("failed to query user")
@@ -32,7 +34,7 @@ func dbGetUserByName(username string) (*User, error) {
 	err := db.Pool.QueryRow(context.Background(), query, username).Scan(&user.ID, &user.Name, &user.Password)
 	if errors.Is(err, pgx.ErrNoRows) {
 		slog.Debug("db: user not found", "username", username)
-		return nil, errors.New("user not found")
+		return nil, ErrUserNotFound
 	} else if err != nil {
 		slog.Error("db: failed to query user", "error", err)
 		return nil, fmt.Errorf("failed to query user")

server/api/user.go

@@ -1,9 +1,11 @@
 package api
 
 import (
+	"errors"
 	"log/slog"
 	"net/http"
 
+	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/render"
 	"github.com/google/uuid"
 )
@@ -35,6 +37,34 @@ func ListUsers(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func GetUser(w http.ResponseWriter, r *http.Request) {
+	slog.Debug("user: entering GetUser handler")
+
+	userID := chi.URLParam(r, "userID")
+	parsed, err := uuid.Parse(userID)
+	if err != nil {
+		render.Render(w, r, ErrInvalidRequest(err))
+		return
+	}
+
+	user, err := dbGetUser(parsed.String())
+	if err != nil {
+		if errors.Is(err, ErrUserNotFound) {
+			render.Render(w, r, ErrNotFound)
+		} else {
+			slog.Error("user: failed to fetch user", "userid", parsed.String(), "error", err)
+			render.Render(w, r, ErrRender(err))
+		}
+		return
+	}
+
+	slog.Debug("user: rendering user", "userid", user.ID, "username", user.Name)
+	if err := render.Render(w, r, NewUserPayloadResponse(user)); err != nil {
+		slog.Error("user: failed to render user", "userid", parsed.String(), "error", err)
+		render.Render(w, r, ErrRender(err))
+	}
+}
+
 func newUserID() uuid.UUID {
 	return uuid.New()
 }

server/db/postgres.go

@@ -17,6 +17,11 @@ func InitPostgres(ctx context.Context) {
 		os.Exit(1)
 	}
 	Pool = pool
+	err = pool.Ping(ctx)
+	if err != nil {
+		slog.Error("Failed to connect to Postgres", "error", err)
+		os.Exit(1)
+	}
 	slog.Info("Connected to Postgres")
 }