Add Feature Delete Job By Tag (#33)

* Update README.md

* Add Feature Delete Job By Tag

Update Readme How to Use Add Tag and Remove Job By Tag
Add Test Create and Delete Job By Tag

* Add Feature Delete Job By Tag

Update Readme How to Use Add Tag and Remove Job By Tag
Add Test Create and Delete Job By Tag

* Add Exported Error Message

Change logic when deleting jobs with tag function

* Update Logic RemoveTag Return Rerr

Update logic to golang best practice error checking

Co-authored-by: John Roesler <johnrroesler@gmail.com>
Co-authored-by: Streppel <streppels@gmail.com>

README.md

@@ -58,6 +58,18 @@ func main() {
     // Do jobs with params
     s2.Every(1).Second().Do(taskWithParams, 1, "hello")
 
+    // Do Jobs with tags
+    // initialize tag
+    tag1 := []string{"tag1"}
+    tag2 := []string{"tag2"}
+
+
+    s2.Every(1).Week().SetTag(tag1).Do(task)
+    s2.Every(1).Week().SetTag(tag2).Do(task)
+
+    // Removing Job Based on Tag
+    scheduler.RemoveJobByTag("tag1")
+
     // Do jobs on specific weekday
     s2.Every(1).Monday().Do(task)
     s2.Every(1).Thursday().Do(task)

gocron.go

@@ -27,6 +27,7 @@ var (
 	ErrNotAFunction        = errors.New("only functions can be schedule into the job queue")
 	ErrPeriodNotSpecified  = errors.New("unspecified job period")
 	ErrNotScheduledWeekday = errors.New("job not scheduled weekly on a weekday")
+	ErrJobNotFoundWithTag  = errors.New("no jobs found with given tag")
 )
 
 type timeUnit int

scheduler.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"reflect"
 	"sort"
+	"strings"
 	"time"
 )
 
@@ -209,6 +210,27 @@ func (s *Scheduler) removeByCondition(shouldRemove func(*Job) bool) {
 	}
 }
 
+// RemoveJobByTag will Remove Jobs by Tag
+func (s *Scheduler) RemoveJobByTag(tag string) error {
+	jobindex, err := s.findJobsIndexByTag(tag)
+	if err != nil {
+		return err
+	}
+	// Remove job if jobindex is valid
+	s.jobs = removeAtIndex(s.jobs, jobindex)
+	return nil
+}
+
+// Find first job index by given string
+func (s *Scheduler) findJobsIndexByTag(tag string) (int, error) {
+	for i, job := range s.jobs {
+		if strings.Contains(strings.Join(job.Tags(), " "), tag) {
+			return i, nil
+		}
+	}
+	return -1, ErrJobNotFoundWithTag
+}
+
 func removeAtIndex(jobs []*Job, i int) []*Job {
 	if i == len(jobs)-1 {
 		return jobs[:i]
@@ -292,6 +314,13 @@ func (s *Scheduler) At(t string) *Scheduler {
 	return s
 }
 
+// SetTag will add tag when creating a job
+func (s *Scheduler) SetTag(t []string) *Scheduler {
+	job := s.getCurrentJob()
+	job.tags = t
+	return s
+}
+
 // StartAt schedules the next run of the Job
 func (s *Scheduler) StartAt(t time.Time) *Scheduler {
 	s.getCurrentJob().nextRun = t

scheduler_test.go

@@ -59,6 +59,15 @@ func TestScheduled(t *testing.T) {
 	}
 }
 
+func TestScheduledWithTag(t *testing.T) {
+	sched := NewScheduler(time.UTC)
+	customtag := []string{"mycustomtag"}
+	sched.Every(1).Hour().SetTag(customtag).Do(task)
+	if !sched.Scheduled(task) {
+		t.Fatal("Task was scheduled but function couldn't find it")
+	}
+}
+
 func TestStartImmediately(t *testing.T) {
 	sched := NewScheduler(time.UTC)
 	now := time.Now().UTC()
@@ -381,6 +390,31 @@ func TestRemoveByRef(t *testing.T) {
 	assert.ElementsMatch(t, []*Job{job2}, scheduler.Jobs())
 }
 
+func TestRemoveByTag(t *testing.T) {
+	scheduler := NewScheduler(time.UTC)
+
+	// Creating 2 Jobs with Unique tags
+	customtag1 := []string{"tag one"}
+	customtag2 := []string{"tag two"}
+	scheduler.Every(1).Minute().SetTag(customtag1).Do(taskWithParams, 1, "hello") // index 0
+	scheduler.Every(1).Minute().SetTag(customtag2).Do(taskWithParams, 2, "world") // index 1
+
+	assert.Equal(t, 2, scheduler.Len(), "Incorrect number of jobs")
+
+	// check Jobs()[0] tags is equal with tag "tag one" (customtag1)
+	assert.Equal(t, scheduler.Jobs()[0].Tags(), customtag1, "Job With Tag 'tag one' is removed from index 0")
+
+	scheduler.RemoveJobByTag("tag one")
+	assert.Equal(t, 1, scheduler.Len(), "Incorrect number of jobs after removing 1 job")
+
+	// check Jobs()[0] tags is equal with tag "tag two" (customtag2) after removing "tag one"
+	assert.Equal(t, scheduler.Jobs()[0].Tags(), customtag2, "Job With Tag 'tag two' is removed from index 0")
+
+	// Removing Non Existent Job with "tag one" because already removed above (will not removing any jobs because tag not match)
+	scheduler.RemoveJobByTag("tag one")
+	assert.Equal(t, 1, scheduler.Len(), "Incorrect number of jobs after removing non-existent job")
+}
+
 func TestJobs(t *testing.T) {
 	s := NewScheduler(time.UTC)
 	s.Every(1).Minute().Do(task)