Add support for cron-tz

docs/advanced-guide/using-cron/page.md

@@ -74,4 +74,33 @@ func main() {
 }
 ```
 
+Gofr also allows to specify timezone against which the schedule will be evaluated.
+
+### Example
+
+```go
+package main
+
+import (
+	"time"
+
+	"gofr.dev/pkg/gofr"
+)
+
+func main() {
+	app := gofr.New()
+
+	// tzdata will be taking care of DST
+	estTimezone, _ := time.LoadLocation("America/New_York")
+
+	// Run the cron job every day at 7AM EST
+	app.AddCronJob("0 7 * * *", "", func(ctx *gofr.Context) {
+		ctx.Logger.Infof("current time is %v", time.Now())
+	}, gofr.WithTimezone(estTimezone))
+
+	app.Run()
+}
+```
+
+
 > #### Check out the example on how to add cron jobs in GoFr: [Visit GitHub](https://github.com/gofr-dev/gofr/blob/main/examples/using-cron-jobs/main.go)

pkg/gofr/cron.go

@@ -34,19 +34,15 @@ type CronFunc func(ctx *Context)
 type Crontab struct {
 	// contains unexported fields
 	ticker    *time.Ticker
+	location  *time.Location
 	jobs      []*job
 	container *container.Container
 
 	mu sync.RWMutex
 }
 
 type job struct {
-	sec       map[int]struct{}
-	min       map[int]struct{}
-	hour      map[int]struct{}
-	day       map[int]struct{}
-	month     map[int]struct{}
-	dayOfWeek map[int]struct{}
+	sec, min, hour, day, month, dayOfWeek map[int]struct{}
 
 	name string
 	fn   CronFunc
@@ -62,22 +58,33 @@ type tick struct {
 }
 
 // NewCron initializes and returns new cron tab.
-func NewCron(cntnr *container.Container) *Crontab {
+func NewCron(cntnr *container.Container, options ...func(*Crontab)) *Crontab {
 	c := &Crontab{
 		ticker:    time.NewTicker(time.Second),
+		location:  time.Local,
 		container: cntnr,
 		jobs:      make([]*job, 0),
 	}
 
+	for _, option := range options {
+		option(c)
+	}
+
 	go func() {
 		for t := range c.ticker.C {
+			t = t.In(c.location)
 			c.runScheduled(t)
 		}
 	}()
 
 	return c
 }
 
+// WithTimezone is a functional option for NewCron to specify timezone against which the cron schedule will be evaluated.
+func WithTimezone(location *time.Location) func(*Crontab) {
+	return func(c *Crontab) { c.location = location }
+}
+
 // this will compile the regex once instead of compiling it each time when it is being called.
 var (
 	matchSpaces = regexp.MustCompile(`\s+`)

pkg/gofr/cron_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"gofr.dev/pkg/gofr/container"
 	"gofr.dev/pkg/gofr/testutil"
 )
 
@@ -203,7 +204,7 @@ func TestCronTab_AddJob(t *testing.T) {
 		},
 	}
 
-	c := NewCron(nil)
+	c := newCronT(t, nil)
 
 	for _, tc := range testCases {
 		err := c.AddJob(tc.schedule, "test-job", fn)
@@ -225,7 +226,7 @@ func TestCronTab_runScheduled(t *testing.T) {
 
 	// can make container nil as we are not testing the internal working of
 	// dependency function as it is user defined
-	c := NewCron(nil)
+	c := newCronT(t, nil)
 
 	// Populate the job array for cron table
 	c.jobs = []*job{j}
@@ -606,3 +607,48 @@ func TestCron_parsePart(t *testing.T) {
 		})
 	}
 }
+
+func TestCron_WithTimezone(t *testing.T) {
+	est, err := time.LoadLocation("America/New_York")
+	require.NoError(t, err, "computing prerequisite timezone")
+
+	tests := []struct {
+		name     string
+		options  []func(*Crontab)
+		expected *time.Location
+	}{
+		{
+			name:     "Factory without options",
+			expected: time.Local,
+		},
+		{
+			name:     "Factory with UTC timezone option",
+			options:  []func(crontab *Crontab){WithTimezone(time.UTC)},
+			expected: time.UTC,
+		},
+		{
+			name:     "Factory with EST/EDT timezone option",
+			options:  []func(crontab *Crontab){WithTimezone(est)},
+			expected: est,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := newCronT(t, nil, test.options...)
+			assert.Equal(t, test.expected, got.location)
+		})
+	}
+}
+
+func newCronT(t *testing.T, cntnr *container.Container, options ...func(*Crontab)) *Crontab {
+	t.Helper()
+
+	c := NewCron(cntnr, options...)
+
+	t.Cleanup(func() {
+		c.ticker.Stop()
+	})
+
+	return c
+}

pkg/gofr/gofr.go

@@ -691,9 +691,9 @@ func (a *App) UseMiddlewareWithContainer(middlewareHandler func(c *container.Con
 // AddCronJob registers a cron job to the cron table.
 // The cron expression can be either a 5-part or 6-part format. The 6-part format includes an
 // optional second field (in beginning) and others being minute, hour, day, month and day of week respectively.
-func (a *App) AddCronJob(schedule, jobName string, job CronFunc) {
+func (a *App) AddCronJob(schedule, jobName string, job CronFunc, options ...func(*Crontab)) {
 	if a.cron == nil {
-		a.cron = NewCron(a.container)
+		a.cron = NewCron(a.container, options...)
 	}
 
 	if err := a.cron.AddJob(schedule, jobName, job); err != nil {