Add timezone support

.gitlab-ci.yml

@@ -0,0 +1,29 @@
+default:
+  image: $CI_REGISTRY/imageroot/buildah:latest
+
+stages:
+  - build
+
+.container:
+  before_script:
+    - podman login -u $CI_REGISTRY_USER --password-stdin $CI_REGISTRY <<<$CI_REGISTRY_PASSWORD
+    - podman login -u $NEXUS_USERNAME --password-stdin $NEXUS_DOCKER_IO <<<$NEXUS_PASSWORD
+
+build-master-container:
+  extends: .container
+  stage: build
+  script:
+    - podman build --build-arg DOCKER_IO=${NEXUS_DOCKER_IO} -t ${CI_REGISTRY_IMAGE}:master .
+    - podman push ${CI_REGISTRY_IMAGE}:master
+  rules:
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
+
+build-tagged-container:
+  extends: .container
+  stage: build
+  script:
+    - podman build --build-arg DOCKER_IO=${NEXUS_DOCKER_IO} -t ${CI_REGISTRY_IMAGE}:${CI_COMMIT_TAG} -t ${CI_REGISTRY_IMAGE}:latest .
+    - podman push ${CI_REGISTRY_IMAGE}:${CI_COMMIT_TAG}
+    - podman push ${CI_REGISTRY_IMAGE}:latest
+  rules:
+    - if: $CI_COMMIT_TAG =~ /^v\d+\.\d+\.\d+/

Dockerfile

@@ -1,14 +1,15 @@
-FROM golang:1.17-alpine AS build
+ARG DOCKER_IO=docker.io
+
+FROM ${DOCKER_IO}/library/golang:1.24-alpine AS build
 
 WORKDIR /code
 
 COPY time.go /code
 RUN go build ./time.go
 
-FROM alpine:latest AS final
-
-MAINTAINER Yehuda Deutsch <yeh@uda.co.il>
+FROM ${DOCKER_IO}/library/alpine:latest AS final
 
+RUN apk add --no-cache tzdata
 WORKDIR /code
 COPY --from=build /code/time /code/time
 

time.go

@@ -1,25 +1,87 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
+	"os"
 	"time"
 )
 
-func getTime(location string) time.Time {
-	loc, _ := time.LoadLocation("UTC")
-	return time.Now().In(loc)
+func getTime(location string) (time.Time, error) {
+	loc, err := time.LoadLocation(location)
+	if err != nil {
+		return time.Now(), err
+	}
+	return time.Now().In(loc), err
+}
+
+var zoneDir string
+
+func loadZoneLocations(path string) []string {
+	var locations []string
+	zoneFiles, _ := os.ReadDir("/usr/share/zoneinfo/" + path)
+	for _, file := range zoneFiles {
+		if file.IsDir() {
+			locations = append(locations, loadZoneLocations(path+"/"+file.Name())...)
+		} else {
+			if _, err := time.LoadLocation((path + "/" + file.Name())[1:]); err != nil {
+				continue
+			}
+			locations = append(locations, (path + "/" + file.Name())[1:])
+		}
+	}
+	return locations
+}
+
+var runtimeLocations = loadZoneLocations(zoneDir)
+
+func mainHandler(w http.ResponseWriter, r *http.Request) {
+	now, err := getTime("UTC")
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprint(w, "Could not get current time")
+		return
+	}
+
+	fmt.Fprintf(w, now.Format("2006-01-02 15:04:05"))
+}
+
+func dayInYearHandler(w http.ResponseWriter, r *http.Request) {
+	now, err := getTime("UTC")
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprint(w, "Could not get current time")
+		return
+	}
+	fmt.Fprintf(w, "%s%d", string(now.Format("06")[1]), now.YearDay())
+}
+
+func timeAtZoneHandler(w http.ResponseWriter, r *http.Request) {
+	timezone := r.PathValue("timezone")
+	now, err := getTime(timezone)
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		fmt.Fprint(w, "Timezone not found")
+		return
+	}
+	fmt.Fprintf(w, now.Format("2006-01-02 15:04:05"))
+}
+
+func ZoneListHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	err := json.NewEncoder(w).Encode(runtimeLocations)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprint(w, "Could not encode zones")
+	}
 }
 
 func main() {
-	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
-		fmt.Fprintf(w, getTime("UTC").Format("2006-01-02 15:04:05"))
-	})
-
-	http.HandleFunc("/diy", func(w http.ResponseWriter, r *http.Request) {
-		now := getTime("UTC")
-		fmt.Fprintf(w, "%s%d", string(now.Format("06")[1]), now.YearDay())
-	})
+	http.HandleFunc("GET /", mainHandler)
+	http.HandleFunc("GET /diy", dayInYearHandler)
+	http.HandleFunc("GET /at/{timezone...}", timeAtZoneHandler)
+	http.HandleFunc("GET /timezones", ZoneListHandler)
 
 	listen := ":8000"
 	fmt.Println("Listening on " + listen)