add: added out_dir to build command

src/please.go

@@ -107,6 +107,7 @@ var opts struct {
 		Rebuild    bool   `long:"rebuild" description:"To force the optimisation and rebuild one or more targets."`
 		NoDownload bool   `long:"nodownload" hidden:"true" description:"Don't download outputs after building. Only applies when using remote build execution."`
 		Download   bool   `long:"download" hidden:"true" description:"Force download of all outputs regardless of original target spec. Only applies when using remote build execution."`
+		OutDir     string `long:"out_dir" optional:"true" description:"Copies build output to given directory"`
 		Args       struct {
 			Targets []core.BuildLabel `positional-arg-name:"targets" description:"Targets to build"`
 		} `positional-args:"true" required:"true"`
@@ -456,7 +457,24 @@ var opts struct {
 var buildFunctions = map[string]func() int{
 	"build": func() int {
 		success, state := runBuild(opts.Build.Args.Targets, true, false, false)
-		return toExitCode(success, state)
+		if !success || opts.Build.OutDir == "" {
+			return toExitCode(success, state)
+		}
+		for _, label := range state.ExpandOriginalLabels() {
+			target := state.Graph.TargetOrDie((label))
+			for _, out := range target.Outputs() {
+				from := filepath.Join(target.OutDir(), out)
+				fm, err := os.Lstat(from)
+				if err != nil {
+					log.Fatalf("Failed to get file mode on build output files: %s", err)
+				}
+				err = fs.CopyFile(from, filepath.Join(opts.Build.OutDir, target.PackageDir(), out), fm.Mode())
+				if err != nil {
+					log.Fatalf("Failed to output build to provided directory: %s", err)
+				}
+			}
+		}
+		return 0
 	},
 	"hash": func() int {
 		if opts.Hash.Update {

test/build_outdir/BUILD

@@ -0,0 +1,8 @@
+subinclude("//test/build_defs")
+
+please_repo_e2e_test(
+    name = "out_dir_test",
+    expected_output = {"bar/foo/testy": "wibble wibble wibble"},
+    plz_command = "plz build //foo:testy --out_dir=bar",
+    repo = "test_repo",
+)

test/build_outdir/test_repo/foo/BUILD_FILE

@@ -0,0 +1,4 @@
+text_file(
+    name = "testy",
+    content = "wibble wibble wibble",
+)