Move sync logic from cmd/sync to libs/sync (#173)

Mechanical change. Ported global variables the logic relied on to a new
`sync.Sync` struct.

cmd/sync/sync.go

@@ -8,8 +8,8 @@ import (
 	"time"
 
 	"github.com/databricks/bricks/cmd/root"
-	"github.com/databricks/bricks/cmd/sync/repofiles"
 	"github.com/databricks/bricks/git"
+	"github.com/databricks/bricks/libs/sync"
 	"github.com/databricks/bricks/project"
 	"github.com/databricks/databricks-sdk-go"
 	"github.com/databricks/databricks-sdk-go/apierr"
@@ -120,11 +120,14 @@ var syncCmd = &cobra.Command{
 			return err
 		}
 
-		root := prj.Root()
-		repoFiles := repofiles.Create(*remotePath, root, wsc)
-		syncCallback := syncCallback(ctx, repoFiles)
-		err = spawnWatchdog(ctx, *interval, syncCallback, *remotePath)
-		return err
+		s := sync.Sync{
+			LocalPath:       prj.Root(),
+			RemotePath:      *remotePath,
+			PersistSnapshot: *persistSnapshot,
+			PollInterval:    *interval,
+		}
+
+		return s.RunWatchdog(ctx, wsc)
 	},
 }
 

cmd/sync/sync_test.go

@@ -1,12 +0,0 @@
-package sync
-
-import (
-	"testing"
-)
-
-func TestItSyncs(t *testing.T) {
-	// ctx := context.Background()
-	// root.RootCmd.SetArgs([]string{"sync"})
-	// err := root.RootCmd.ExecuteContext(ctx)
-	// assert.NoError(t, err)
-}

internal/sync_test.go

@@ -14,7 +14,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/databricks/bricks/cmd/sync"
+	_ "github.com/databricks/bricks/cmd/sync"
+	"github.com/databricks/bricks/libs/sync"
 	"github.com/databricks/bricks/libs/testfile"
 	"github.com/databricks/databricks-sdk-go"
 	"github.com/databricks/databricks-sdk-go/client"

libs/sync/sync.go

@@ -0,0 +1,26 @@
+package sync
+
+import (
+	"context"
+	"time"
+
+	"github.com/databricks/bricks/libs/sync/repofiles"
+	"github.com/databricks/databricks-sdk-go"
+)
+
+type Sync struct {
+	LocalPath  string
+	RemotePath string
+
+	PersistSnapshot bool
+
+	PollInterval time.Duration
+}
+
+// RunWatchdog kicks off a polling loop to monitor local changes and synchronize
+// them to the remote workspace path.
+func (s *Sync) RunWatchdog(ctx context.Context, wsc *databricks.WorkspaceClient) error {
+	repoFiles := repofiles.Create(s.RemotePath, s.LocalPath, wsc)
+	syncCallback := syncCallback(ctx, repoFiles)
+	return spawnWatchdog(ctx, s.PollInterval, syncCallback, s.RemotePath, s.PersistSnapshot)
+}

libs/sync/watchdog.go

@@ -6,7 +6,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/databricks/bricks/cmd/sync/repofiles"
+	"github.com/databricks/bricks/libs/sync/repofiles"
 	"github.com/databricks/bricks/project"
 	"golang.org/x/sync/errgroup"
 )
@@ -16,6 +16,8 @@ type watchdog struct {
 	ticker  *time.Ticker
 	wg      sync.WaitGroup
 	failure error // data race? make channel?
+
+	persistSnapshot bool
 }
 
 // See https://docs.databricks.com/resources/limits.html#limits-api-rate-limits for per api
@@ -70,9 +72,11 @@ func syncCallback(ctx context.Context, repoFiles *repofiles.RepoFiles) func(loca
 func spawnWatchdog(ctx context.Context,
 	interval time.Duration,
 	applyDiff func(diff) error,
-	remotePath string) error {
+	remotePath string,
+	persistSnapshot bool) error {
 	w := &watchdog{
-		ticker: time.NewTicker(interval),
+		ticker:          time.NewTicker(interval),
+		persistSnapshot: persistSnapshot,
 	}
 	w.wg.Add(1)
 	go w.main(ctx, applyDiff, remotePath)
@@ -90,7 +94,7 @@ func (w *watchdog) main(ctx context.Context, applyDiff func(diff) error, remoteP
 		w.failure = err
 		return
 	}
-	if *persistSnapshot {
+	if w.persistSnapshot {
 		err := snapshot.loadSnapshot(ctx)
 		if err != nil {
 			log.Printf("[ERROR] cannot load snapshot: %s", err)
@@ -128,7 +132,7 @@ func (w *watchdog) main(ctx context.Context, applyDiff func(diff) error, remoteP
 				w.failure = err
 				return
 			}
-			if *persistSnapshot {
+			if w.persistSnapshot {
 				err = snapshot.storeSnapshot(ctx)
 				if err != nil {
 					log.Printf("[ERROR] cannot store snapshot: %s", err)