add main runloop with fake command executor

executor.go

@@ -0,0 +1,18 @@
+package cron
+
+type Executor interface {
+ Execute(command string) error
+}
+
+type FakeExecutor struct {
+ Commands []string
+}
+
+func (executor *FakeExecutor) Execute(command string) error {
+ executor.Commands = append(executor.Commands, command)
+ return nil
+}
+
+func CreateFakeExecutor() *FakeExecutor {
+ return &FakeExecutor{make([]string, 0)}
+}

job.go

@@ -0,0 +1,6 @@
+package cron
+
+type Job struct {
+ Schedule Schedule
+ Command string
+}

server.go

@@ -0,0 +1,41 @@
+package cron
+
+import(
+ "time"
+)
+
+type Server struct {
+ executor Executor
+ ticker *time.Ticker
+ jobs []Job
+}
+
+func Start(executor Executor, jobs []Job, interval time.Duration) *Server {
+ ticker := time.NewTicker(interval)
+
+ server := &Server{
+ executor: executor,
+ jobs: jobs,
+ ticker: ticker,
+ }
+
+ go func () {
+ for now := range ticker.C {
+ server.Once(now)
+ }
+ }()
+
+ return server
+}
+
+func (server *Server) Once(now time.Time) {
+ for _, job := range server.jobs {
+ if job.Schedule.ShouldRun(now) {
+ server.executor.Execute(job.Command)
+ }
+ }
+}
+
+func (server *Server) Stop() {
+ server.ticker.Stop()
+}

server_test.go

@@ -0,0 +1,69 @@
+package cron
+
+import(
+ "testing"
+ "time"
+)
+
+
+func TestOnceWithNoJobsDoesNothing(t *testing.T) {
+ executor := CreateFakeExecutor()
+ server := &Server{
+ executor: executor,
+ jobs: make([]Job, 0),
+ }
+
+ server.Once(time.Now())
+
+ if len(executor.Commands) > 0 {
+ t.Error("Should not have run commands")
+ }
+}
+
+func TestOnceWithAWildcardJobRunsIt(t *testing.T) {
+ executor := CreateFakeExecutor()
+ server := &Server{
+ executor: executor,
+ jobs: []Job{
+ Job{Parse("* * * * * *"), "echo hi"},
+ },
+ }
+
+ server.Once(time.Now())
+
+ if len(executor.Commands) != 1 {
+ t.Error("Should have run 1 command")
+ }
+
+ if executor.Commands[0] != "echo hi" {
+ t.Error("Should have run 'echo hi'")
+ }
+}
+
+func TestStartStopWithSingleJob(t *testing.T) {
+ executor := CreateFakeExecutor()
+ server := Start(
+ executor,
+ []Job{Job{Parse("* * * * * *"), "echo hi"}},
+ time.Millisecond * 10,
+ )
+
+ timer := time.NewTimer(time.Millisecond * 12)
+ <-timer.C
+
+ server.Stop()
+
+ if len(executor.Commands) != 1 {
+ t.Error("Should have run 1 command")
+ }
+
+ if executor.Commands[0] != "echo hi" {
+ t.Error("Should have run 'echo hi'")
+ }
+
+ timer = time.NewTimer(time.Millisecond * 12)
+ <-timer.C
+ if len(executor.Commands) != 1 {
+ t.Error("Should have run 1 command")
+ }
+}