From fd6609f8c47c6acb8737036b8f2911a034a4eb16 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Fri, 9 Nov 2018 10:40:14 -0500
Subject: [PATCH 1/8] Remove use of custom errorf from CmdUpdate.

---
 claat/cmd/update.go | 9 +++++++--
 claat/main.go       | 6 ++++--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/claat/cmd/update.go b/claat/cmd/update.go
index 8569cfe12..b03d9c7fc 100644
--- a/claat/cmd/update.go
+++ b/claat/cmd/update.go
@@ -41,7 +41,8 @@ type CmdUpdateOptions struct {
 }
 
 // CmdUpdate is the "claat update ..." subcommand.
-func CmdUpdate(opts CmdUpdateOptions) {
+// It returns true if the command succeeded, false otherwise.
+func CmdUpdate(opts CmdUpdateOptions) bool {
 	roots := flag.Args()
 	if len(roots) == 0 {
 		roots = []string{"."}
@@ -69,14 +70,18 @@ func CmdUpdate(opts CmdUpdateOptions) {
 			ch <- &result{d, meta, err}
 		}(d)
 	}
+
+	errs := []error{}
 	for range dirs {
 		res := <-ch
 		if res.err != nil {
-			errorf(reportErr, res.dir, res.err)
+			errs = append(errs, res.err)
+			log.Printf(reportErr, res.dir, res.err)
 		} else {
 			log.Printf(reportOk, res.meta.ID)
 		}
 	}
+	return len(errs) == 0
 }
 
 // updateCodelab reads metadata from a dir/codelab.json file,
diff --git a/claat/main.go b/claat/main.go
index 5ecf98534..ad4032c67 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -78,11 +78,13 @@ func main() {
 	case "build":
 		cmd.CmdBuild()
 	case "update":
-		cmd.CmdUpdate(cmd.CmdUpdateOptions{
+		if ok := cmd.CmdUpdate(cmd.CmdUpdateOptions{
 			AuthToken: *authToken,
 			GlobalGA:  *globalGA,
 			Prefix:    *prefix,
-		})
+		}); !ok {
+			os.Exit(1)
+		}
 	case "help":
 		usage()
 	case "version":

From 4e4e82cbfbf92751b190090ed9681d40fb4e81c4 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Fri, 9 Nov 2018 10:45:53 -0500
Subject: [PATCH 2/8] Remove use of custom error from CmdExport.

---
 claat/cmd/export.go | 8 ++++++--
 claat/main.go       | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/claat/cmd/export.go b/claat/cmd/export.go
index 942b4ebb3..3a640de63 100644
--- a/claat/cmd/export.go
+++ b/claat/cmd/export.go
@@ -45,7 +45,8 @@ type CmdExportOptions struct {
 }
 
 // CmdExport is the "claat export ..." subcommand.
-func CmdExport(opts CmdExportOptions) {
+// It returns true if the command succeeded, false otherwise.
+func CmdExport(opts CmdExportOptions) bool {
 	if flag.NArg() == 0 {
 		log.Fatalf("Need at least one source. Try '-h' for options.")
 	}
@@ -62,14 +63,17 @@ func CmdExport(opts CmdExportOptions) {
 			ch <- &result{src, meta, err}
 		}(src)
 	}
+	errs := []error{}
 	for range args {
 		res := <-ch
 		if res.err != nil {
-			errorf(reportErr, res.src, res.err)
+			errs = append(errs, res.err)
+			log.Printf(reportErr, res.src, res.err)
 		} else if !isStdout(opts.Output) {
 			log.Printf(reportOk, res.meta.ID)
 		}
 	}
+	return len(errs) == 0
 }
 
 // exportCodelab fetches codelab src from either local disk or remote,
diff --git a/claat/main.go b/claat/main.go
index ad4032c67..1f720475c 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -65,14 +65,16 @@ func main() {
 
 	switch os.Args[1] {
 	case "export":
-		cmd.CmdExport(cmd.CmdExportOptions{
+		if ok := cmd.CmdExport(cmd.CmdExportOptions{
 			AuthToken: *authToken,
 			Expenv:    *expenv,
 			GlobalGA:  *globalGA,
 			Output:    *output,
 			Prefix:    *prefix,
 			Tmplout:   *tmplout,
-		})
+		}); !ok {
+			os.Exit(1)
+		}
 	case "serve":
 		cmd.CmdServe(*addr)
 	case "build":

From b67d222c3f10d5cdfc99c3165ec6e966c039ed22 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Fri, 9 Nov 2018 10:47:06 -0500
Subject: [PATCH 3/8] Remove custom errorf from util.go.

---
 claat/cmd/util.go | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/claat/cmd/util.go b/claat/cmd/util.go
index 2afa09f25..69af9b851 100644
--- a/claat/cmd/util.go
+++ b/claat/cmd/util.go
@@ -21,7 +21,6 @@ package cmd
 
 import (
 	"encoding/json"
-	"log"
 	"sync"
 
 	// allow parsers to register themselves
@@ -54,14 +53,6 @@ func isStdout(filename string) bool {
 	return filename == stdout
 }
 
-// errorf calls log.Printf with fmt and args, and sets non-zero exit code.
-func errorf(format string, args ...interface{}) {
-	log.Printf(format, args...)
-	exitMu.Lock()
-	Exit = 1
-	exitMu.Unlock()
-}
-
 // ParseExtraVars parses extra template variables from command line.
 // extra is any additional arguments to pass to format templates. Should be formatted as JSON objects of string:string KV pairs.
 func ParseExtraVars(extra string) map[string]string {

From 6d6179f852e3b8339b7524969ff8d48b19892a76 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Fri, 9 Nov 2018 11:02:28 -0500
Subject: [PATCH 4/8] Remove unnecessary constants from util.go.

---
 claat/cmd/util.go | 7 +------
 claat/main.go     | 1 -
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/claat/cmd/util.go b/claat/cmd/util.go
index 69af9b851..ab8bc6802 100644
--- a/claat/cmd/util.go
+++ b/claat/cmd/util.go
@@ -21,7 +21,6 @@ package cmd
 
 import (
 	"encoding/json"
-	"sync"
 
 	// allow parsers to register themselves
 	_ "github.com/googlecodelabs/tools/claat/parser/gdoc"
@@ -42,11 +41,7 @@ const (
 	reportOk  = "ok\t%s"
 )
 
-var (
-	Exit      int               // program exit code
-	exitMu    sync.Mutex        // guards exit
-	ExtraVars map[string]string // Extra template variables passed on the command line.
-)
+var ExtraVars map[string]string // Extra template variables passed on the command line.
 
 // isStdout reports whether filename is stdout.
 func isStdout(filename string) bool {
diff --git a/claat/main.go b/claat/main.go
index 1f720475c..a57f98177 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -94,7 +94,6 @@ func main() {
 	default:
 		log.Fatalf("Unknown subcommand. Try '-h' for options.")
 	}
-	os.Exit(cmd.Exit)
 }
 
 // usage prints usageText and program arguments to stderr.

From 15994cdb3ef6adba9d49f584ea5a39875f1a9ea9 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Fri, 9 Nov 2018 11:10:16 -0500
Subject: [PATCH 5/8] Remove custom errorf from ParseExtraVars.

---
 claat/cmd/util.go | 10 ++++++----
 claat/main.go     |  7 ++++++-
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/claat/cmd/util.go b/claat/cmd/util.go
index ab8bc6802..60443c031 100644
--- a/claat/cmd/util.go
+++ b/claat/cmd/util.go
@@ -21,6 +21,7 @@ package cmd
 
 import (
 	"encoding/json"
+	"log"
 
 	// allow parsers to register themselves
 	_ "github.com/googlecodelabs/tools/claat/parser/gdoc"
@@ -50,15 +51,16 @@ func isStdout(filename string) bool {
 
 // ParseExtraVars parses extra template variables from command line.
 // extra is any additional arguments to pass to format templates. Should be formatted as JSON objects of string:string KV pairs.
-func ParseExtraVars(extra string) map[string]string {
+func ParseExtraVars(extra string) (map[string]string, error) {
 	vars := make(map[string]string)
 	if extra == "" {
-		return vars
+		return vars, nil
 	}
 	b := []byte(extra)
 	err := json.Unmarshal(b, &vars)
 	if err != nil {
-		errorf("Error parsing additional template data: %v", err)
+		log.Printf("Error parsing additional template data: %v", err)
+		return nil, err
 	}
-	return vars
+	return vars, nil
 }
diff --git a/claat/main.go b/claat/main.go
index a57f98177..3245d4ec7 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -61,7 +61,12 @@ func main() {
 
 	flag.Usage = usage
 	flag.CommandLine.Parse(os.Args[2:])
-	cmd.ExtraVars = cmd.ParseExtraVars(*extra)
+
+	var err error
+	cmd.ExtraVars, err = cmd.ParseExtraVars(*extra)
+	if err != nil {
+		os.Exit(1)
+	}
 
 	switch os.Args[1] {
 	case "export":

From abc04689fd62699e71563248b80667356f9003d4 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Thu, 15 Nov 2018 17:16:48 -0500
Subject: [PATCH 6/8] Change information flow model so command functions send
 error codes up.

The caller (main) is responsible for invoking os.Exit.
---
 claat/cmd/build.go  |  5 ++++-
 claat/cmd/export.go | 10 +++++-----
 claat/cmd/serve.go  |  4 +++-
 claat/cmd/update.go | 10 +++++-----
 claat/main.go       | 19 +++++++++----------
 5 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/claat/cmd/build.go b/claat/cmd/build.go
index 01b53284f..c1a8344f8 100644
--- a/claat/cmd/build.go
+++ b/claat/cmd/build.go
@@ -29,7 +29,9 @@ import (
 	"sync"
 )
 
-func CmdBuild() {
+// CmdBuild is the "claat build ..." subcommand.
+// It returns a process exit code.
+func CmdBuild() int {
 	const depsDir = "bower_components"
 	var codelabElem = []byte(`
 <link rel="import" href="../bower_components/google-codelab-elements/google-codelab-elements.html">
@@ -46,6 +48,7 @@ func CmdBuild() {
 	if err := writeFile(filepath.Join("elements", "codelab.html"), codelabElem); err != nil {
 		log.Fatalf(err.Error())
 	}
+	return 0
 }
 
 func writeFile(name string, content []byte) error {
diff --git a/claat/cmd/export.go b/claat/cmd/export.go
index 3a640de63..90ade5bf1 100644
--- a/claat/cmd/export.go
+++ b/claat/cmd/export.go
@@ -45,8 +45,9 @@ type CmdExportOptions struct {
 }
 
 // CmdExport is the "claat export ..." subcommand.
-// It returns true if the command succeeded, false otherwise.
-func CmdExport(opts CmdExportOptions) bool {
+// It returns a process exit code.
+func CmdExport(opts CmdExportOptions) int {
+	exitCode := 0
 	if flag.NArg() == 0 {
 		log.Fatalf("Need at least one source. Try '-h' for options.")
 	}
@@ -63,17 +64,16 @@ func CmdExport(opts CmdExportOptions) bool {
 			ch <- &result{src, meta, err}
 		}(src)
 	}
-	errs := []error{}
 	for range args {
 		res := <-ch
 		if res.err != nil {
-			errs = append(errs, res.err)
+			exitCode = 1
 			log.Printf(reportErr, res.src, res.err)
 		} else if !isStdout(opts.Output) {
 			log.Printf(reportOk, res.meta.ID)
 		}
 	}
-	return len(errs) == 0
+	return exitCode
 }
 
 // exportCodelab fetches codelab src from either local disk or remote,
diff --git a/claat/cmd/serve.go b/claat/cmd/serve.go
index cba2cad7a..5b3ff60d4 100644
--- a/claat/cmd/serve.go
+++ b/claat/cmd/serve.go
@@ -23,7 +23,8 @@ import (
 
 // CmdServe is the "claat serve ..." subcommand.
 // addr is the hostname and port to bind the web server to.
-func CmdServe(addr string) {
+// It returns a process exit code.
+func CmdServe(addr string) int {
 	CmdBuild()
 	http.Handle("/", http.FileServer(http.Dir(".")))
 	log.Printf("Serving codelabs on %s, opening browser tab now...", addr)
@@ -33,6 +34,7 @@ func CmdServe(addr string) {
 	}()
 	openBrowser("http://" + addr)
 	log.Fatalf("claat serve: %v", <-ch)
+	return 0
 }
 
 // openBrowser tries to open the URL in a browser.
diff --git a/claat/cmd/update.go b/claat/cmd/update.go
index b03d9c7fc..1d699a5c6 100644
--- a/claat/cmd/update.go
+++ b/claat/cmd/update.go
@@ -41,8 +41,8 @@ type CmdUpdateOptions struct {
 }
 
 // CmdUpdate is the "claat update ..." subcommand.
-// It returns true if the command succeeded, false otherwise.
-func CmdUpdate(opts CmdUpdateOptions) bool {
+// It returns a process exit code.
+func CmdUpdate(opts CmdUpdateOptions) int {
 	roots := flag.Args()
 	if len(roots) == 0 {
 		roots = []string{"."}
@@ -71,17 +71,17 @@ func CmdUpdate(opts CmdUpdateOptions) bool {
 		}(d)
 	}
 
-	errs := []error{}
+	exitCode := 0
 	for range dirs {
 		res := <-ch
 		if res.err != nil {
-			errs = append(errs, res.err)
+			exitCode = 1
 			log.Printf(reportErr, res.dir, res.err)
 		} else {
 			log.Printf(reportOk, res.meta.ID)
 		}
 	}
-	return len(errs) == 0
+	return exitCode
 }
 
 // updateCodelab reads metadata from a dir/codelab.json file,
diff --git a/claat/main.go b/claat/main.go
index 3245d4ec7..d83cd1fab 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -68,30 +68,27 @@ func main() {
 		os.Exit(1)
 	}
 
+	exitCode := 0
 	switch os.Args[1] {
 	case "export":
-		if ok := cmd.CmdExport(cmd.CmdExportOptions{
+		exitCode = cmd.CmdExport(cmd.CmdExportOptions{
 			AuthToken: *authToken,
 			Expenv:    *expenv,
 			GlobalGA:  *globalGA,
 			Output:    *output,
 			Prefix:    *prefix,
 			Tmplout:   *tmplout,
-		}); !ok {
-			os.Exit(1)
-		}
+		})
 	case "serve":
-		cmd.CmdServe(*addr)
+		exitCode = cmd.CmdServe(*addr)
 	case "build":
-		cmd.CmdBuild()
+		exitCode = cmd.CmdBuild()
 	case "update":
-		if ok := cmd.CmdUpdate(cmd.CmdUpdateOptions{
+		exitCode = cmd.CmdUpdate(cmd.CmdUpdateOptions{
 			AuthToken: *authToken,
 			GlobalGA:  *globalGA,
 			Prefix:    *prefix,
-		}); !ok {
-			os.Exit(1)
-		}
+		})
 	case "help":
 		usage()
 	case "version":
@@ -99,6 +96,8 @@ func main() {
 	default:
 		log.Fatalf("Unknown subcommand. Try '-h' for options.")
 	}
+
+	os.Exit(exitCode)
 }
 
 // usage prints usageText and program arguments to stderr.

From 80ce6526477b0bbced673f26202760077a091546 Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Mon, 19 Nov 2018 23:29:21 +0000
Subject: [PATCH 7/8] Switch from zero-init to declaration for exit codes.

No semantic impact; this is purely stylistic.
---
 claat/cmd/export.go | 2 +-
 claat/cmd/update.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/claat/cmd/export.go b/claat/cmd/export.go
index 90ade5bf1..43e5f2123 100644
--- a/claat/cmd/export.go
+++ b/claat/cmd/export.go
@@ -47,7 +47,7 @@ type CmdExportOptions struct {
 // CmdExport is the "claat export ..." subcommand.
 // It returns a process exit code.
 func CmdExport(opts CmdExportOptions) int {
-	exitCode := 0
+	var exitCode int
 	if flag.NArg() == 0 {
 		log.Fatalf("Need at least one source. Try '-h' for options.")
 	}
diff --git a/claat/cmd/update.go b/claat/cmd/update.go
index 1d699a5c6..d07349148 100644
--- a/claat/cmd/update.go
+++ b/claat/cmd/update.go
@@ -71,7 +71,7 @@ func CmdUpdate(opts CmdUpdateOptions) int {
 		}(d)
 	}
 
-	exitCode := 0
+	var exitCode int
 	for range dirs {
 		res := <-ch
 		if res.err != nil {

From 0c4910cd8c9e0cfc2576506beb0c93a99fad3f0e Mon Sep 17 00:00:00 2001
From: Cassie Recher <cerech@google.com>
Date: Tue, 20 Nov 2018 15:27:19 +0000
Subject: [PATCH 8/8] Move ParseExtrVars to main.go.

It was only being used in main, so it didn't make much sense to keep in
utils.
---
 claat/cmd/export.go |  9 ++++++---
 claat/cmd/update.go |  4 +++-
 claat/cmd/util.go   | 20 --------------------
 claat/main.go       | 22 ++++++++++++++++++++--
 4 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/claat/cmd/export.go b/claat/cmd/export.go
index 43e5f2123..7afa484f8 100644
--- a/claat/cmd/export.go
+++ b/claat/cmd/export.go
@@ -34,6 +34,8 @@ type CmdExportOptions struct {
 	AuthToken string
 	// Expenv is the codelab environment to export to.
 	Expenv string
+	// ExtraVars is extra template variables.
+	ExtraVars map[string]string
 	// GlobalGA is the global Google Analytics account to use.
 	GlobalGA string
 	// Output is the output directory, or "-" for stdout.
@@ -120,12 +122,13 @@ func exportCodelab(src string, opts CmdExportOptions) (*types.Meta, error) {
 		}
 	}
 	// write codelab and its metadata to disk
-	return meta, writeCodelab(dir, clab.Codelab, ctx)
+	return meta, writeCodelab(dir, clab.Codelab, opts.ExtraVars, ctx)
 }
 
 // writeCodelab stores codelab main content in ctx.Format and its metadata
 // in JSON format on disk.
-func writeCodelab(dir string, clab *types.Codelab, ctx *types.Context) error {
+// extraVars is extra variables to pass into the template context.
+func writeCodelab(dir string, clab *types.Codelab, extraVars map[string]string, ctx *types.Context) error {
 	// output to stdout does not include metadata
 	if !isStdout(dir) {
 		// make sure codelab dir exists
@@ -153,7 +156,7 @@ func writeCodelab(dir string, clab *types.Codelab, ctx *types.Context) error {
 		GlobalGA: ctx.MainGA,
 		Meta:     &clab.Meta,
 		Steps:    clab.Steps,
-		Extra:    ExtraVars,
+		Extra:    extraVars,
 	}}
 	if ctx.Format != "offline" {
 		w := os.Stdout
diff --git a/claat/cmd/update.go b/claat/cmd/update.go
index d07349148..de061c738 100644
--- a/claat/cmd/update.go
+++ b/claat/cmd/update.go
@@ -34,6 +34,8 @@ import (
 type CmdUpdateOptions struct {
 	// AuthToken is the token to use for the Drive API.
 	AuthToken string
+	// ExtraVars is extra template variables.
+	ExtraVars map[string]string
 	// GlobalGA is the global Google Analytics account to use.
 	GlobalGA string
 	// Prefix is a URL prefix to prepend when using HTML format.
@@ -127,7 +129,7 @@ func updateCodelab(dir string, opts CmdUpdateOptions) (*types.Meta, error) {
 	}
 
 	// write codelab and its metadata
-	if err := writeCodelab(newdir, clab.Codelab, &meta.Context); err != nil {
+	if err := writeCodelab(newdir, clab.Codelab, opts.ExtraVars, &meta.Context); err != nil {
 		return nil, err
 	}
 
diff --git a/claat/cmd/util.go b/claat/cmd/util.go
index 60443c031..e65ab8c28 100644
--- a/claat/cmd/util.go
+++ b/claat/cmd/util.go
@@ -20,8 +20,6 @@
 package cmd
 
 import (
-	"encoding/json"
-	"log"
 
 	// allow parsers to register themselves
 	_ "github.com/googlecodelabs/tools/claat/parser/gdoc"
@@ -42,25 +40,7 @@ const (
 	reportOk  = "ok\t%s"
 )
 
-var ExtraVars map[string]string // Extra template variables passed on the command line.
-
 // isStdout reports whether filename is stdout.
 func isStdout(filename string) bool {
 	return filename == stdout
 }
-
-// ParseExtraVars parses extra template variables from command line.
-// extra is any additional arguments to pass to format templates. Should be formatted as JSON objects of string:string KV pairs.
-func ParseExtraVars(extra string) (map[string]string, error) {
-	vars := make(map[string]string)
-	if extra == "" {
-		return vars, nil
-	}
-	b := []byte(extra)
-	err := json.Unmarshal(b, &vars)
-	if err != nil {
-		log.Printf("Error parsing additional template data: %v", err)
-		return nil, err
-	}
-	return vars, nil
-}
diff --git a/claat/main.go b/claat/main.go
index d83cd1fab..b5991ef47 100644
--- a/claat/main.go
+++ b/claat/main.go
@@ -20,6 +20,7 @@
 package main
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
 	"log"
@@ -62,8 +63,7 @@ func main() {
 	flag.Usage = usage
 	flag.CommandLine.Parse(os.Args[2:])
 
-	var err error
-	cmd.ExtraVars, err = cmd.ParseExtraVars(*extra)
+	extraVars, err := ParseExtraVars(*extra)
 	if err != nil {
 		os.Exit(1)
 	}
@@ -74,6 +74,7 @@ func main() {
 		exitCode = cmd.CmdExport(cmd.CmdExportOptions{
 			AuthToken: *authToken,
 			Expenv:    *expenv,
+			ExtraVars: extraVars,
 			GlobalGA:  *globalGA,
 			Output:    *output,
 			Prefix:    *prefix,
@@ -86,6 +87,7 @@ func main() {
 	case "update":
 		exitCode = cmd.CmdUpdate(cmd.CmdUpdateOptions{
 			AuthToken: *authToken,
+			ExtraVars: extraVars,
 			GlobalGA:  *globalGA,
 			Prefix:    *prefix,
 		})
@@ -100,6 +102,22 @@ func main() {
 	os.Exit(exitCode)
 }
 
+// ParseExtraVars parses extra template variables from command line.
+// extra is any additional arguments to pass to format templates. Should be formatted as JSON objects of string:string KV pairs.
+func ParseExtraVars(extra string) (map[string]string, error) {
+	vars := make(map[string]string)
+	if extra == "" {
+		return vars, nil
+	}
+	b := []byte(extra)
+	err := json.Unmarshal(b, &vars)
+	if err != nil {
+		log.Printf("Error parsing additional template data: %v", err)
+		return nil, err
+	}
+	return vars, nil
+}
+
 // usage prints usageText and program arguments to stderr.
 func usage() {
 	fmt.Fprint(os.Stderr, usageText)