CBG-4413: Add logging capture to Sync Function diagnostic API (#7938)

Author: bbrks

channels/sync_runner.go

@@ -116,12 +116,10 @@ type SyncRunner struct {
 	expiry            *uint32             // document expiry (in seconds) specified via expiry() callback
 }
 
-func NewSyncRunner(ctx context.Context, funcSource string, timeout time.Duration) (*SyncRunner, error) {
+func NewSyncRunnerWithLogging(ctx context.Context, funcSource string, timeout time.Duration, errorLogFunc, infoLogFunc func(string)) (*SyncRunner, error) {
 	funcSource = wrappedFuncSource(funcSource)
 	runner := &SyncRunner{}
-	err := runner.InitWithLogging(funcSource, timeout,
-		func(s string) { base.ErrorfCtx(ctx, base.KeyJavascript.String()+": Sync %s", base.UD(s)) },
-		func(s string) { base.InfofCtx(ctx, base.KeyJavascript, "Sync %s", base.UD(s)) })
+	err := runner.InitWithLogging(funcSource, timeout, errorLogFunc, infoLogFunc)
 	if err != nil {
 		return nil, err
 	}
@@ -212,6 +210,12 @@ func NewSyncRunner(ctx context.Context, funcSource string, timeout time.Duration
 	return runner, nil
 }
 
+func NewSyncRunner(ctx context.Context, funcSource string, timeout time.Duration) (*SyncRunner, error) {
+	errorLogFunc := func(s string) { base.ErrorfCtx(ctx, base.KeyJavascript.String()+": Sync %s", base.UD(s)) }
+	infoLogFunc := func(s string) { base.InfofCtx(ctx, base.KeyJavascript, "Sync %s", base.UD(s)) }
+	return NewSyncRunnerWithLogging(ctx, funcSource, timeout, errorLogFunc, infoLogFunc)
+}
+
 func (runner *SyncRunner) SetFunction(funcSource string) (bool, error) {
 	funcSource = wrappedFuncSource(funcSource)
 	return runner.JSRunner.SetFunction(funcSource)

db/crud.go

@@ -1697,8 +1697,7 @@ func (db *DatabaseCollectionWithUser) PutExistingRevWithBody(ctx context.Context
 // SyncFnDryrun Runs the given document body through a sync function and returns expiry, channels doc was placed in,
 // access map for users, roles, handler errors and sync fn exceptions.
 // If syncFn is provided, it will be used instead of the one configured on the database.
-func (db *DatabaseCollectionWithUser) SyncFnDryrun(ctx context.Context, newDoc, oldDoc *Document, syncFn string) (*channels.ChannelMapperOutput, error) {
-
+func (db *DatabaseCollectionWithUser) SyncFnDryrun(ctx context.Context, newDoc, oldDoc *Document, syncFn string, errorLogFunc, infoLogFunc func(string)) (*channels.ChannelMapperOutput, error) {
 	mutableBody, metaMap, _, err := db.prepareSyncFn(oldDoc, newDoc)
 	if err != nil {
 		base.InfofCtx(ctx, base.KeyDiagnostic, "Failed to prepare to run sync function: %v", err)
@@ -1709,32 +1708,30 @@ func (db *DatabaseCollectionWithUser) SyncFnDryrun(ctx context.Context, newDoc,
 	if err != nil {
 		return nil, err
 	}
-	var output *channels.ChannelMapperOutput
-	var syncErr error
-	if syncFn == "" && db.ChannelMapper != nil {
-		output, err = db.ChannelMapper.MapToChannelsAndAccess(ctx, mutableBody, string(oldDoc._rawBody), metaMap, syncOptions)
-		if err != nil {
-			return nil, &base.SyncFnDryRunError{Err: err}
-		}
-	} else {
-		if syncFn == "" {
+
+	// fetch configured sync function if one is not provided
+	if syncFn == "" {
+		if db.ChannelMapper != nil {
+			syncFn = db.ChannelMapper.Function()
+		} else {
 			scopeAndCollectionName := db.ScopeAndCollectionName()
 			syncFn = channels.GetDefaultSyncFunction(scopeAndCollectionName.Scope, scopeAndCollectionName.Collection)
 		}
-		jsTimeout := time.Duration(base.DefaultJavascriptTimeoutSecs) * time.Second
-		syncRunner, err := channels.NewSyncRunner(ctx, syncFn, jsTimeout)
-		if err != nil {
-			return nil, fmt.Errorf("failed to create sync runner: %v", err)
-		}
-		jsOutput, err := syncRunner.Call(ctx, mutableBody, string(oldDoc._rawBody), metaMap, syncOptions)
-		if err != nil {
+	}
 
-			return nil, &base.SyncFnDryRunError{Err: err}
-		}
-		output = jsOutput.(*channels.ChannelMapperOutput)
+	// create new sync runner instance for this dry run
+	jsTimeout := time.Duration(base.DefaultJavascriptTimeoutSecs) * time.Second
+	syncRunner, err := channels.NewSyncRunnerWithLogging(ctx, syncFn, jsTimeout, errorLogFunc, infoLogFunc)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create sync runner: %v", err)
+	}
+
+	jsOutput, err := syncRunner.Call(ctx, mutableBody, sgbucket.JSONString(oldDoc._rawBody), metaMap, syncOptions)
+	if err != nil {
+		return nil, &base.SyncFnDryRunError{Err: err}
 	}
 
-	return output, syncErr
+	return jsOutput.(*channels.ChannelMapperOutput), nil
 }
 
 // revTreeConflictCheck checks for conflicts in the rev tree history and returns the parent revid, currentRevIndex

rest/diagnostic_doc_api.go

@@ -21,12 +21,18 @@ import (
 	"github.com/couchbase/sync_gateway/db"
 )
 
+type SyncFnDryRunLogging struct {
+	Errors []string `json:"errors"`
+	Info   []string `json:"info"`
+}
+
 type SyncFnDryRun struct {
-	Channels  base.Set           `json:"channels"`
-	Access    channels.AccessMap `json:"access"`
-	Roles     channels.AccessMap `json:"roles"`
-	Exception string             `json:"exception"`
-	Expiry    *uint32            `json:"expiry,omitempty"`
+	Channels  base.Set            `json:"channels"`
+	Access    channels.AccessMap  `json:"access"`
+	Roles     channels.AccessMap  `json:"roles"`
+	Exception string              `json:"exception,omitempty"`
+	Expiry    *uint32             `json:"expiry,omitempty"`
+	Logging   SyncFnDryRunLogging `json:"logging"`
 }
 
 type ImportFilterDryRun struct {
@@ -83,7 +89,7 @@ func (h *handler) handleSyncFnDryRun() error {
 	}
 
 	if syncDryRunPayload.Doc == nil && docid == "" {
-		return base.HTTPErrorf(http.StatusBadRequest, "no docid or document provided")
+		return base.HTTPErrorf(http.StatusBadRequest, "no doc_id or document provided")
 	}
 
 	oldDoc := &db.Document{ID: docid}
@@ -144,7 +150,16 @@ func (h *handler) handleSyncFnDryRun() error {
 	newRev := db.CreateRevIDWithBytes(generation, matchRev, rawDocBytes)
 	newDoc.RevID = newRev
 
-	output, err := h.collection.SyncFnDryrun(h.ctx(), newDoc, oldDoc, syncDryRunPayload.Function)
+	logErrors := make([]string, 0)
+	logInfo := make([]string, 0)
+	errorLogFn := func(s string) {
+		logErrors = append(logErrors, s)
+	}
+	infoLogFn := func(s string) {
+		logInfo = append(logInfo, s)
+	}
+
+	output, err := h.collection.SyncFnDryrun(h.ctx(), newDoc, oldDoc, syncDryRunPayload.Function, errorLogFn, infoLogFn)
 	if err != nil {
 		var syncFnDryRunErr *base.SyncFnDryRunError
 		if !errors.As(err, &syncFnDryRunErr) {
@@ -154,6 +169,7 @@ func (h *handler) handleSyncFnDryRun() error {
 		errMsg := syncFnDryRunErr.Error()
 		resp := SyncFnDryRun{
 			Exception: errMsg,
+			Logging:   SyncFnDryRunLogging{Errors: logErrors, Info: logInfo},
 		}
 		h.writeJSON(resp)
 		return nil
@@ -169,6 +185,7 @@ func (h *handler) handleSyncFnDryRun() error {
 		output.Roles,
 		errorMsg,
 		output.Expiry,
+		SyncFnDryRunLogging{Errors: logErrors, Info: logInfo},
 	}
 	h.writeJSON(resp)
 	return nil