Add support for a custom gid.

Permit the package author to specify a custom gid by providing a
io.whalebrew.config.customgid label.

packages/package.go

@@ -32,6 +32,7 @@ type Package struct {
 	MountMissingVolumes bool     `yaml:"mount_missing_volumes,omitempty"`
 	RequiredVersion     string   `yaml:"required_version,omitempty"`
 	PathArguments       []string `yaml:"path_arguments,omitempty"`
+	CustomGid string `yaml:"customgid,omitempty"`
 }
 
 // NewPackageFromImage creates a package from a given image name,
@@ -127,6 +128,12 @@ func NewPackageFromImage(image string, imageInspect types.ImageInspect) (*Packag
 					return pkg, fmt.Errorf("unexpected io.whalebrew.config.missing_volumes value: %s expecting error, skip or mount", missingVolumes)
 				}
 			}
+
+			if customgid, ok := labels["io.whalebrew.config.customgid"]; ok {
+				if err := yaml.Unmarshal([]byte(customgid), &pkg.CustomGid); err != nil {
+					return pkg, err
+				}
+			}
 		}
 	}
 

packages/package_test.go

@@ -36,6 +36,7 @@ func TestNewPackageFromImage(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, pkg.Name, "foo")
 	assert.Equal(t, pkg.Image, "whalebrew/foo:bar")
+	assert.Equal(t, pkg.CustomGid, "")
 
 	assert.Equal(t, "ws", mustNewTestPkg(t, "io.whalebrew.name", "ws").Name)
 	assert.Equal(t, "whalebrew/whalesay", mustNewTestPkg(t, "io.whalebrew.name", "ws").Image)
@@ -53,6 +54,7 @@ func TestNewPackageFromImage(t *testing.T) {
 
 	assert.False(t, mustNewTestPkg(t, "io.whalebrew.config.missing_volumes", "error").MountMissingVolumes)
 	assert.False(t, mustNewTestPkg(t, "io.whalebrew.config.missing_volumes", "error").SkipMissingVolumes)
+	assert.Equal(t, "42", mustNewTestPkg(t, "io.whalebrew.config.customgid", "42").CustomGid)
 
 	assert.False(t, mustNewTestPkg(t, "any", "ws").MountMissingVolumes)
 	assert.False(t, mustNewTestPkg(t, "any", "other").SkipMissingVolumes)

run/docker.go

@@ -75,10 +75,17 @@ func (d *Docker) Run(p *packages.Package, e *Execution) error {
 		dockerArgs = append(dockerArgs, "-v")
 		dockerArgs = append(dockerArgs, volume)
 	}
+
 	if !p.KeepContainerUser {
 		if e.User != nil {
 			dockerArgs = append(dockerArgs, "-u")
-			dockerArgs = append(dockerArgs, e.User.Uid+":"+e.User.Gid)
+			if p.CustomGid != "" {
+				dockerArgs = append(dockerArgs, e.User.Uid+":"+p.CustomGid)
+			} else {
+				// does this have test..
+				dockerArgs = append(dockerArgs, e.User.Uid+":"+e.User.Gid)
+			}
+
 		}
 	}
 	dockerArgs = append(dockerArgs, p.Image)

run/docker_test.go

@@ -98,4 +98,33 @@ func TestDockerRun(t *testing.T) {
 			Gid: "4086",
 		},
 	}))
+
+	// Test customgid functionality.
+	d.Exec = func(argv0 string, argv []string, envv []string) (err error) {
+		assert.Equal(t, "docker", argv0)
+		assert.Equal(
+			t,
+			[]string{
+				"docker", "run", "--interactive", "--rm",
+				"--workdir", "/workdir", "--init",
+				"-u", "2048:1234",
+				"alpine",
+				"-h", "hello", "world",
+			},
+			argv,
+		)
+		assert.Equal(t, os.Environ(), envv)
+		return nil
+	}
+	assert.NoError(t, d.Run(&packages.Package{
+		Image:     "alpine",
+		CustomGid: "1234",
+	}, &run.Execution{
+		WorkingDir: "/workdir",
+		User: &user.User{
+			Uid: "2048",
+			Gid: "4086",
+		},
+		Args: []string{"-h", "hello", "world"},
+	}))
 }