added strict mode option

cli/cli.go

@@ -12,6 +12,7 @@ import (
 
 var envVars = make(temgo.EnvVars)
 var inlineFlag = flag.String("i", "", "-i filename")
+var strictFlag = flag.Bool("s", false, "-s")
 
 func init() {
 	for _, e := range os.Environ() {
@@ -49,8 +50,10 @@ func replace(rw *bufio.ReadWriter, file *os.File) {
 		must(rw.Flush())
 	}
 
-	if temgo.ContainsVariable(bytes) {
-		str := envVars.ReplaceVariables(bytes)
+	tg := temgo.New(envVars, *strictFlag)
+	if tg.ContainsVariable(bytes) {
+		str, err := tg.ReplaceVariables(bytes)
+		must(err)
 		if file != nil {
 			truncate(file)
 		}
@@ -63,7 +66,7 @@ func replace(rw *bufio.ReadWriter, file *os.File) {
 // fatal
 func must(err error) {
 	if err != nil {
-		println("Err:", err.Error())
+		println("Error:", err.Error())
 		os.Exit(1)
 	}
 }

cli/cli_test.go

@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"os"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestReplace(t *testing.T) {
@@ -26,8 +28,8 @@ func TestReplace(t *testing.T) {
 		rw := bufio.NewReadWriter(bufio.NewReader(r), bufio.NewWriter(w))
 		replace(rw, nil)
 		out := w.Bytes()
-		if string(out) != testCase.expected {
-			t.Errorf("\nWant: \t%q\nGot: \t%q", string(testCase.expected), string(out))
+		if diff := cmp.Diff(string(out), testCase.expected); diff != "" {
+			t.Errorf("Failed for case: '%v'.\nResult differs:\n%s", string(testCase.in), diff)
 		}
 	}
 }

temgo/temgo.go

@@ -1,34 +1,59 @@
 package temgo
 
 import (
+	"errors"
 	"regexp"
 	"strings"
 )
 
 type EnvVars map[string]string
 
-// following the posix standards
-var templatePattern = regexp.MustCompile(`\{{2} ([a-zA-Z_]+[a-zA-Z_0-9]*) }{2}`)
+type Temgo struct {
+	envVars EnvVars
+	pattern *regexp.Regexp
+	strict  bool
+}
+
+func New(envs EnvVars, strict bool) *Temgo {
+	return &Temgo{
+		envVars: envs,
+		// following the posix standards
+		pattern: regexp.MustCompile(`{{2} ([a-zA-Z_]+[a-zA-Z_0-9]*) }{2}`),
+		strict:  strict,
+	}
+}
 
-func ContainsVariable(str []byte) bool {
-	return templatePattern.Match(str)
+func (t *Temgo) ContainsVariable(str []byte) bool {
+	return t.pattern.Match(str)
 }
 
-func replace(e *EnvVars, bytes []byte) []byte {
-	list := templatePattern.FindAllStringSubmatch(string(bytes), -1)
+func (t *Temgo) replace(bytes []byte) (result []byte, errList []string) {
+	result = bytes
+	list := t.pattern.FindAllStringSubmatch(string(bytes), -1)
 	for _, match := range list {
-		str, ok := (*e)[match[1]]
+		str, ok := t.envVars[match[1]]
 		if !ok {
-			continue // variable not set
+			if t.strict {
+				errList = append(errList, "variable "+match[1]+" is not set")
+			}
+			continue
 		}
-		bytes = []byte(strings.Replace(string(bytes), match[0], str, -1))
+		result = []byte(strings.Replace(string(result), match[0], str, -1))
 	}
-	return bytes
+	return result, errList
 }
 
-func (e *EnvVars) ReplaceVariables(str []byte) []byte {
-	result := templatePattern.ReplaceAllFunc(str, func(b []byte) []byte {
-		return replace(e, b)
+func (t *Temgo) ReplaceVariables(str []byte) ([]byte, error) {
+	var errList []string
+	result := t.pattern.ReplaceAllFunc(str, func(b []byte) []byte {
+		r, err := t.replace(b)
+		if err != nil {
+			errList = append(errList, err...)
+		}
+		return r
 	})
-	return result
+	if len(errList) > 0 {
+		return nil, errors.New(strings.Join(errList, "\n"))
+	}
+	return result, nil
 }

temgo/temgo_test.go

@@ -1,8 +1,11 @@
 package temgo_test
 
 import (
-	"github.com/malud/temgo/temgo"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/malud/temgo/temgo"
 )
 
 var containsTests = []struct {
@@ -15,38 +18,59 @@ var containsTests = []struct {
 	{"This text contains a variable with number {{ AUTH0_DOMAIN }}.", true},
 }
 
-var replaceVars = &temgo.EnvVars{
+var replaceVars = temgo.EnvVars{
 	"VAR_A":        "/etc/ptc",
 	"VARIABLE_C":   "color:256",
 	"S":            "short",
 	"AUTH0_DOMAIN": "samples.auth0.com",
 }
 
 var replaceTests = []struct {
-	in  string
-	out string
+	in   string
+	out  string
+	fail bool
 }{
-	{"This dummy text contains a path to {{ VAR_A }}", "This dummy text contains a path to /etc/ptc"},
-	{"Some text with a {{ VARIABLE_C }} variable!", "Some text with a color:256 variable!"},
-	{"This is a {{ S }} text.", "This is a short text."},
-	{"This is a {{ S }} text with a {{ FAILVAR}} and some vars [\"{{ VAR_A }}\",'{{ VARIABLE_C }}'].", "This is a short text with a {{ FAILVAR}} and some vars [\"/etc/ptc\",'color:256']."},
-	{"This text contains a variable with number: '{{ AUTH0_DOMAIN }}'.", "This text contains a variable with number: 'samples.auth0.com'."},
+	{"This dummy text contains a path to {{ VAR_A }}", "This dummy text contains a path to /etc/ptc", false},
+	{"Some text with a {{ VARIABLE_C }} variable!", "Some text with a color:256 variable!", false},
+	{"This is a {{ S }} text.", "This is a short text.", false},
+	{"This is a {{ S }} text with a {{ FAILVAR}} and some vars [\"{{ VAR_A }}\",'{{ VARIABLE_C }}'].", "This is a short text with a {{ FAILVAR}} and some vars [\"/etc/ptc\",'color:256'].", false},
+	{"This text contains a variable with number: '{{ AUTH0_DOMAIN }}'.", "This text contains a variable with number: 'samples.auth0.com'.", false},
+	{"This text contains a {{ VAR }} which is {{ NOT_SET }} in environment variables.", "variable VAR is not set\nvariable NOT_SET is not set", true},
 }
 
 func TestContainsVariable(t *testing.T) {
+	tg := temgo.New(nil, false)
 	for _, test := range containsTests {
-		r := temgo.ContainsVariable([]byte(test.in))
-		if r != test.out {
-			t.Errorf("Failed for case: '%v'. Expected: %v Got: %v", test.in, test.out, r)
+		r := tg.ContainsVariable([]byte(test.in))
+		if diff := cmp.Diff(r, test.out); diff != "" {
+			t.Errorf("Failed for case: '%v'.\nResult differs:\n%s", test.in, diff)
 		}
 	}
 }
 
 func TestEnvVars_ReplaceVariables(t *testing.T) {
+	tg := temgo.New(replaceVars, false)
+	for _, test := range replaceTests {
+		bytes, err := tg.ReplaceVariables([]byte(test.in))
+		if !test.fail && err != nil {
+			t.Fatal(err)
+		}
+		if diff := cmp.Diff(string(bytes), test.out); diff != "" && !test.fail {
+			t.Errorf("Failed for case: '%v'.\nResult differs:\n%s", test.in, diff)
+		}
+	}
+}
+
+func TestEnvVars_ReplaceVariablesStrict(t *testing.T) {
+	tg := temgo.New(replaceVars, true)
 	for _, test := range replaceTests {
-		bytes := replaceVars.ReplaceVariables([]byte(test.in))
-		if string(bytes) != test.out {
-			t.Errorf("Failed for case: '%v'. Expected: %v Got: %v", test.in, test.out, string(bytes))
+		r, err := tg.ReplaceVariables([]byte(test.in))
+		if test.fail && err != nil {
+			if diff := cmp.Diff(err.Error(), test.out); diff != "" {
+				t.Errorf("Failed for case: '%v'.\nResult differs:\n%s", test.in, diff)
+			}
+		} else if diff := cmp.Diff(string(r), test.out); diff != "" {
+			t.Errorf("Failed for case: '%v'.\nResult differs:\n%s", test.in, diff)
 		}
 	}
 }