feat: add local schema diff

If no remote URI is specified for schema diff it will attempt to diff the local project

closes #2174

cmd/ftl/cmd_schema_diff.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/url"
 	"os"
@@ -17,24 +18,48 @@ import (
 	"github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/ftlv1connect"
 	schemapb "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/schema"
 	"github.com/TBD54566975/ftl/backend/schema"
+	"github.com/TBD54566975/ftl/buildengine"
+	"github.com/TBD54566975/ftl/common/projectconfig"
 	"github.com/TBD54566975/ftl/internal/log"
 	"github.com/TBD54566975/ftl/internal/rpc"
 )
 
 type schemaDiffCmd struct {
-	OtherEndpoint url.URL `arg:"" help:"Other endpoint URL to compare against."`
+	OtherEndpoint url.URL `arg:"" help:"Other endpoint URL to compare against. If this is not specified then ftl will perform a diff against the local schema." optional:""`
 	Color         bool    `help:"Enable colored output regardless of TTY."`
 }
 
-func (d *schemaDiffCmd) Run(ctx context.Context, currentURL *url.URL) error {
-	other, err := schemaForURL(ctx, d.OtherEndpoint)
+func (d *schemaDiffCmd) Run(ctx context.Context, currentURL *url.URL, projConfig projectconfig.Config) error {
+	var other *schema.Schema
+	var err error
+	sameModulesOnly := false
+	if d.OtherEndpoint.String() == "" {
+		sameModulesOnly = true
+		other, err = localSchema(ctx, projConfig)
+	} else {
+		other, err = schemaForURL(ctx, d.OtherEndpoint)
+	}
+
 	if err != nil {
 		return fmt.Errorf("failed to get other schema: %w", err)
 	}
 	current, err := schemaForURL(ctx, *currentURL)
 	if err != nil {
 		return fmt.Errorf("failed to get current schema: %w", err)
 	}
+	if sameModulesOnly {
+		tempModules := current.Modules
+		current.Modules = []*schema.Module{}
+		moduleMap := map[string]*schema.Module{}
+		for _, i := range tempModules {
+			moduleMap[i.Name] = i
+		}
+		for _, i := range other.Modules {
+			if mod, ok := moduleMap[i.Name]; ok {
+				current.Modules = append(current.Modules, mod)
+			}
+		}
+	}
 
 	edits := myers.ComputeEdits(span.URIFromPath(""), other.String(), current.String())
 	diff := fmt.Sprint(gotextdiff.ToUnified(d.OtherEndpoint.String(), currentURL.String(), other.String(), edits))
@@ -57,6 +82,30 @@ func (d *schemaDiffCmd) Run(ctx context.Context, currentURL *url.URL) error {
 	return nil
 }
 
+func localSchema(ctx context.Context, projectConfig projectconfig.Config) (*schema.Schema, error) {
+	pb := &schema.Schema{}
+	found := false
+	tried := ""
+	modules, err := buildengine.DiscoverModules(ctx, projectConfig.AbsModuleDirs())
+	if err != nil {
+		return nil, fmt.Errorf("failed to discover modules %w", err)
+	}
+	for _, moduleSettings := range modules {
+		mod, err := schema.ModuleFromProtoFile(moduleSettings.Config.Abs().Schema)
+		if err != nil {
+			tried += fmt.Sprintf(" failed to read schema file %s; did you run ftl build?", moduleSettings.Config.Abs().Schema)
+		} else {
+			found = true
+			pb.Modules = append(pb.Modules, mod)
+		}
+
+	}
+	if !found {
+		return nil, errors.New(tried)
+	}
+	return pb, nil
+}
+
 func schemaForURL(ctx context.Context, url url.URL) (*schema.Schema, error) {
 	client := rpc.Dial(ftlv1connect.NewControllerServiceClient, url.String(), log.Error)
 	resp, err := client.PullSchema(ctx, connect.NewRequest(&ftlv1.PullSchemaRequest{}))

cmd/ftl/integration_test.go

@@ -143,3 +143,30 @@ func testImportExport(t *testing.T, object string) {
 		}),
 	)
 }
+
+func TestLocalSchemaDiff(t *testing.T) {
+	newVerb := `
+//ftl:verb
+func NewFunction(ctx context.Context, req TimeRequest) (TimeResponse, error) {
+	return TimeResponse{Time: time.Now()}, nil
+}
+`
+	Run(t, "",
+		CopyModule("time"),
+		Deploy("time"),
+		ExecWithOutput("ftl", []string{"schema", "diff"}, func(output string) {
+			assert.Equal(t, "", output)
+		}),
+		EditFile("time", func(bytes []byte) []byte {
+			s := string(bytes)
+			s += newVerb
+			return []byte(s)
+		}, "time.go"),
+		Build("time"),
+		// We exit with code 1 when there is a difference
+		ExpectError(
+			ExecWithOutput("ftl", []string{"schema", "diff"}, func(output string) {
+				assert.Contains(t, output, "-  verb newFunction(time.TimeRequest) time.TimeResponse")
+			}), "exit status 1"),
+	)
+}

integration/actions.go

@@ -23,11 +23,12 @@ import (
 	"github.com/kballard/go-shellquote"
 	"github.com/otiai10/copy"
 
+	"github.com/TBD54566975/scaffolder"
+
 	ftlv1 "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1"
 	schemapb "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/schema"
 	ftlexec "github.com/TBD54566975/ftl/internal/exec"
 	"github.com/TBD54566975/ftl/internal/log"
-	"github.com/TBD54566975/scaffolder"
 )
 
 // Scaffold a directory relative to the testdata directory to a directory relative to the working directory.
@@ -280,6 +281,21 @@ func WriteFile(path string, content []byte) Action {
 	}
 }
 
+// EditFile edits a file in a module
+func EditFile(module string, editFunc func([]byte) []byte, path ...string) Action {
+	return func(t testing.TB, ic TestContext) {
+		parts := []string{ic.workDir, module}
+		parts = append(parts, path...)
+		file := filepath.Join(parts...)
+		Infof("Editing %s", file)
+		contents, err := os.ReadFile(file)
+		assert.NoError(t, err)
+		contents = editFunc(contents)
+		err = os.WriteFile(file, contents, os.FileMode(0))
+		assert.NoError(t, err)
+	}
+}
+
 type Obj map[string]any
 
 // Call a verb.