From dcd9b60cf5f729f47c4c0e072703b585b6a9de17 Mon Sep 17 00:00:00 2001
From: Christian Weichel <chris@gitpod.io>
Date: Tue, 13 Dec 2022 10:32:54 +0000
Subject: [PATCH] Add support for local default arg overrides

---
 README.md                    |  8 ++++++++
 pkg/leeway/workspace.go      | 23 ++++++++++++++++++++---
 pkg/leeway/workspace_test.go | 33 +++++++++++++++++++++++++++++++++
 pkg/testutil/testutil.go     | 19 +++++++++++++++++--
 4 files changed, 78 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 572ae98..e243adb 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,14 @@ defaultArgs:
   key: value
 ```
 
+Users can override, and provide additional default arguments using a `WORKSPACE.args.yaml` file in the workspace root. This is useful for providing local overrides which you might not want to commit to Git.
+The `WORKSPACE.args.yaml` takes key value pairs which become available as build arguments. The values herein take precedence over the default arguments in the `WORKSPACE.yaml`.
+
+```YAML
+foo: bar
+key: value
+```
+
 ## Component
 Place a `BUILD.yaml` in a folder somewhere in the workspace to make that folder a component. A `BUILD.yaml` primarily contains the packages of that components, but can also contain constant values (think of them as metadata). For example:
 ```YAML
diff --git a/pkg/leeway/workspace.go b/pkg/leeway/workspace.go
index 7833113..f391093 100644
--- a/pkg/leeway/workspace.go
+++ b/pkg/leeway/workspace.go
@@ -227,16 +227,33 @@ func loadWorkspace(ctx context.Context, path string, args Arguments, variant str
 	workspace.ignores = ignores
 	log.WithField("ignores", workspace.ignores).Debug("computed workspace ignores")
 
+	if workspace.ArgumentDefaults == nil {
+		workspace.ArgumentDefaults = make(map[string]string)
+	}
 	if len(opts.ArgumentDefaults) > 0 {
-		if workspace.ArgumentDefaults == nil {
-			workspace.ArgumentDefaults = make(map[string]string)
-		}
 		for k, v := range opts.ArgumentDefaults {
 			workspace.ArgumentDefaults[k] = v
 		}
 		log.WithField("rootDefaultArgs", opts.ArgumentDefaults).Debug("installed root workspace defaults")
 	}
 
+	defaultArgsFN := filepath.Join(path, "WORKSPACE.args.yaml")
+	if fc, err := os.ReadFile(defaultArgsFN); err == nil {
+		defargs := make(map[string]string)
+		err = yaml.Unmarshal(fc, &defargs)
+		if err != nil {
+			return Workspace{}, xerrors.Errorf("cannot unmarshal %s: %w", defaultArgsFN, err)
+		}
+		for k, v := range defargs {
+			workspace.ArgumentDefaults[k] = v
+		}
+		log.WithField("content", defargs).WithField("filename", defaultArgsFN).Debug("applied workspace default args file")
+	} else if os.IsNotExist(err) {
+		// ignore
+	} else {
+		return Workspace{}, xerrors.Errorf("cannot read %s: %w", defaultArgsFN, err)
+	}
+
 	log.WithField("defaultArgs", workspace.ArgumentDefaults).Debug("applying workspace defaults")
 	for key, val := range workspace.ArgumentDefaults {
 		if args == nil {
diff --git a/pkg/leeway/workspace_test.go b/pkg/leeway/workspace_test.go
index a24a716..ee4bee3 100644
--- a/pkg/leeway/workspace_test.go
+++ b/pkg/leeway/workspace_test.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/gitpod-io/leeway/pkg/leeway"
 	"github.com/gitpod-io/leeway/pkg/testutil"
 )
 
@@ -33,6 +34,38 @@ func TestFixtureLoadWorkspace(t *testing.T) {
 			StdoutSubs:        []string{"deeper/pkg0\nwsa\nwsa/pkg0\nwsa/pkg1"},
 			FixturePath:       "fixtures/load-workspace.yaml",
 		},
+		{
+			Name:              "workspace args file",
+			T:                 t,
+			Args:              []string{"describe", "comp:pkg"},
+			NoNestedWorkspace: true,
+			ExitCode:          0,
+			StdoutSubs:        []string{"foobar"},
+			Fixture: &testutil.Setup{
+				Files: map[string]string{"WORKSPACE.args.yaml": "msg: foobar"},
+				Workspace: leeway.Workspace{
+					ArgumentDefaults: map[string]string{
+						"msg": "blabla",
+					},
+				},
+				Components: []testutil.Component{
+					{
+						Location: "comp",
+						Packages: []leeway.Package{
+							{
+								PackageInternal: leeway.PackageInternal{
+									Name: "pkg",
+									Type: leeway.GenericPackage,
+								},
+								Config: leeway.GenericPkgConfig{
+									Commands: [][]string{{"echo", "${msg}"}},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			Name: "environment manifest",
 			T:    t,
diff --git a/pkg/testutil/testutil.go b/pkg/testutil/testutil.go
index da4f5c0..3e96dbc 100644
--- a/pkg/testutil/testutil.go
+++ b/pkg/testutil/testutil.go
@@ -17,8 +17,9 @@ import (
 )
 
 type Setup struct {
-	Workspace  leeway.Workspace `yaml:"workspace"`
-	Components []Component      `yaml:"components"`
+	Workspace  leeway.Workspace  `yaml:"workspace"`
+	Components []Component       `yaml:"components"`
+	Files      map[string]string `yaml:"files"`
 }
 
 type Component struct {
@@ -60,6 +61,20 @@ func (s Setup) Materialize() (workspaceRoot string, err error) {
 	if err != nil {
 		return
 	}
+	for fn, content := range s.Files {
+		fn = filepath.Join(workspaceRoot, fn)
+		err = os.MkdirAll(filepath.Dir(fn), 0755)
+		if errors.Is(err, os.ErrExist) {
+			err = nil
+		}
+		if err != nil {
+			return
+		}
+		err = os.WriteFile(fn, []byte(content), 0644)
+		if err != nil {
+			return
+		}
+	}
 
 	for _, comp := range s.Components {
 		err = os.MkdirAll(filepath.Join(workspaceRoot, comp.Location), 0755)