add simple cron implementation

backend/controller/cronjobs/cronjobs.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"strings"
 	"time"
 
 	"connectrpc.com/connect"
@@ -13,6 +12,7 @@ import (
 	ftlv1 "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1"
 	schemapb "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/schema"
 	"github.com/TBD54566975/ftl/backend/schema"
+	"github.com/TBD54566975/ftl/internal/cron"
 	"github.com/TBD54566975/ftl/internal/log"
 	"github.com/TBD54566975/ftl/internal/model"
 	"github.com/TBD54566975/ftl/internal/slices"
@@ -99,17 +99,21 @@ func (s *Service) CreatedDeployment(ctx context.Context, deploymentKey model.Dep
 	newJobs := []dal.CronJob{}
 	for _, decl := range module.Decls {
 		if verb, ok := decl.(*schema.Verb); ok {
-			if cron, ok := verb.GetMetadataCronJob().Get(); ok {
+			if cronJob, ok := verb.GetMetadataCronJob().Get(); ok {
 				//TODO: remove prefix trimming when swapping out cron lib
-				schedule := strings.TrimPrefix(cron.String(), "+cron ")
+				schedule, err := cron.Parse(cronJob.CronString())
+				if err != nil {
+					logger.Errorf(err, "failed to parse cron schedule %q", cronJob.CronString())
+					continue
+				}
 
 				start := time.Now().UTC()
-				next, err := gronx.NextTickAfter(schedule, start, false)
+				next, err := cron.NextAfter(schedule, start, false)
 				if err != nil {
 					logger.Errorf(err, "failed to calculate next execution for cron job %v:%v with schedule %q", deploymentKey, verb.Name, schedule)
 					continue
 				}
-				created, err := s.dal.CreateCronJob(ctx, deploymentKey, module.Name, verb.Name, schedule, start, next)
+				created, err := s.dal.CreateCronJob(ctx, deploymentKey, module.Name, verb.Name, schedule.String(), start, next)
 				if err != nil {
 					logger.Errorf(err, "failed to create cron job %v:%v", deploymentKey, verb.Name)
 				} else {

backend/controller/scheduledtask/scheduledtask_test.go

@@ -2,13 +2,10 @@ package scheduledtask
 
 import (
 	"context"
-	"fmt"
 	"sync/atomic"
 	"testing"
 	"time"
 
-	"github.com/adhocore/gronx"
-
 	"github.com/alecthomas/assert/v2"
 	"github.com/benbjohnson/clock"
 	"github.com/jpillora/backoff"
@@ -61,11 +58,3 @@ func TestCron(t *testing.T) {
 	assert.True(t, singletonCount.Load() >= 5 && singletonCount.Load() < 10, "expected singletonCount to be >= 5 but was %d", singletonCount.Load())
 	assert.True(t, multiCount.Load() >= 20 && multiCount.Load() < 30, "expected multiCount to be >= 20 but was %d", multiCount.Load())
 }
-
-func TestCronLib(t *testing.T) {
-	expr := "0 0 1 1 *"
-	allowCurrent := true                                                        // includes current time as well
-	prevTime, err := gronx.PrevTickBefore(expr, time.Now().UTC(), allowCurrent) // gives time.Time, error
-	assert.NoError(t, err)
-	fmt.Printf("prev time: %s", prevTime.String())
-}

backend/schema/metadatacronjob.go

@@ -21,10 +21,14 @@ var _ Metadata = (*MetadataCronJob)(nil)
 
 func (m *MetadataCronJob) Position() Position { return m.Pos }
 func (m *MetadataCronJob) String() string {
-	pattern := strings.Join(slices.Map(m.Components, func(component *CronJobComponent) string {
+
+	return fmt.Sprintf("+cron %s", m.CronString())
+}
+
+func (m *MetadataCronJob) CronString() string {
+	return strings.Join(slices.Map(m.Components, func(component *CronJobComponent) string {
 		return component.String()
 	}), " ")
-	return fmt.Sprintf("+cron %s", pattern)
 }
 
 func (m *MetadataCronJob) schemaChildren() []Node {

backend/schema/validate.go

@@ -9,12 +9,12 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/adhocore/gronx"
 	"github.com/alecthomas/participle/v2"
 	"github.com/alecthomas/participle/v2/lexer"
 	"github.com/alecthomas/types/optional"
 	"golang.org/x/exp/maps"
 
+	"github.com/TBD54566975/ftl/internal/cron"
 	"github.com/TBD54566975/ftl/internal/errors"
 	dc "github.com/TBD54566975/ftl/internal/reflect"
 )
@@ -159,9 +159,11 @@ func Validate(schema *Schema) (*Schema, error) {
 						hasCron = true
 
 						//TODO: remove prefix trimming when swapping out cron lib
-						schedule := strings.TrimPrefix(md.String(), "+cron ")
-						if valid := gronx.New().IsValid(schedule); !valid {
-							merr = append(merr, errorf(md, "invalid cron schedule %q", schedule))
+						schedule, err := cron.Parse(md.CronString())
+						if err != nil {
+							merr = append(merr, err)
+						} else if err := cron.Validate(schedule); err != nil {
+							merr = append(merr, err)
 						}
 
 					case *MetadataCalls, *MetadataDatabases, *MetadataAlias:

buildengine/testdata/projects/another/go.mod

@@ -10,7 +10,6 @@ require (
 	connectrpc.com/otelconnect v0.7.0 // indirect
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/TBD54566975/scaffolder v0.8.0 // indirect
-	github.com/adhocore/gronx v1.8.1 // indirect
 	github.com/alecthomas/concurrency v0.0.2 // indirect
 	github.com/alecthomas/kong v0.9.0 // indirect
 	github.com/alecthomas/participle/v2 v2.1.1 // indirect

go-runtime/compile/testdata/one/go.mod

@@ -12,7 +12,6 @@ require (
 	connectrpc.com/otelconnect v0.7.0 // indirect
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/TBD54566975/scaffolder v0.8.0 // indirect
-	github.com/adhocore/gronx v1.8.1 // indirect
 	github.com/alecthomas/concurrency v0.0.2 // indirect
 	github.com/alecthomas/kong v0.9.0 // indirect
 	github.com/alecthomas/participle/v2 v2.1.1 // indirect

go-runtime/compile/testdata/two/go.mod

@@ -12,7 +12,6 @@ require (
 	connectrpc.com/otelconnect v0.7.0 // indirect
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/TBD54566975/scaffolder v0.8.0 // indirect
-	github.com/adhocore/gronx v1.8.1 // indirect
 	github.com/alecthomas/concurrency v0.0.2 // indirect
 	github.com/alecthomas/kong v0.9.0 // indirect
 	github.com/alecthomas/participle/v2 v2.1.1 // indirect