Merge pull request #57 from cortexapps/shawn/default-vars

Support defaults on env vars

Author: shawnburke

agent/server/snykbroker/acceptfile/accept_file_test.go

@@ -81,6 +81,11 @@ func TestAcceptFileValidate(t *testing.T) {
 			valid:   true,
 			envVars: map[string]string{"API": "value", "OTHER": "othervalue"},
 		},
+		{
+			content: `{"vars": ["${API:foo.api.com}"], "private": []}`,
+			valid:   true,
+			envVars: map[string]string{},
+		},
 	}
 
 	for _, file := range files {
@@ -119,9 +124,10 @@ func TestAcceptFileValidate(t *testing.T) {
 func TestRenderEnvVars(t *testing.T) {
 
 	vars := map[string]string{
-		"API":    "value",
-		"OTHER":  "othervalue",
-		"plugin": "nope",
+		"API":         "value",
+		"OTHER":       "othervalue",
+		"plugin":      "nope",
+		"NOT_MISSING": "set_value",
 	}
 
 	for k, v := range vars {
@@ -136,13 +142,13 @@ func TestRenderEnvVars(t *testing.T) {
 	cfg := axonConfig.NewAgentEnvConfig()
 
 	content := `{
-		"$vars":["${env:API}", "${OTHER}", "${plugin:foo}", "${OTHER}"], "private": []}`
+		"$vars":["${env:API}", "${OTHER}", "${plugin:foo}", "${OTHER}","${MISSING:default_value}","${NOT_MISSING:default_value}"], "private": []}`
 
 	af, err := NewAcceptFile([]byte(content), cfg, nil)
 	require.NoError(t, err)
 	rendered, err := af.Render(zap.NewNop())
 	require.NoError(t, err)
-	expected := `{"$vars":["${API}","${OTHER}","{{plugin:foo}}","${OTHER}"],"private":[{"method":"any","origin":"http://localhost:80","path":"/__axon/*"}],"public":[]}`
+	expected := `{"$vars":["${API}","${OTHER}","{{plugin:foo}}","${OTHER}","default_value","${NOT_MISSING}"],"private":[{"method":"any","origin":"http://localhost:80","path":"/__axon/*"}],"public":[]}`
 	require.Equal(t, expected, string(rendered), "Rendered accept file does not match expected output")
 }
 

agent/server/snykbroker/acceptfile/resolver.go

@@ -23,6 +23,23 @@ func preProcessContent(content []byte) ([]byte, error) {
 	reEnv := regexp.MustCompile(`\$\{env:([^}]+)\}`)
 	content = reEnv.ReplaceAll(content, []byte("${$1}"))
 
+	// Change all ${FOO:default_value} to default_value
+	reEnvWithDefault := regexp.MustCompile(`\$\{([^:}]+):([^}]+)\}`)
+	content = reEnvWithDefault.ReplaceAllFunc(content, func(match []byte) []byte {
+		parts := reEnvWithDefault.FindSubmatch(match)
+
+		// inspect the value to see if it is set in the environment
+		// if it is set, return ${FOO}, otherwise return the default value as a literal
+		if len(parts) == 3 {
+			varName := string(parts[1])
+			if varIsSet(varName) {
+				return fmt.Appendf(nil, "${%s}", varName)
+			}
+			return parts[2] // return the default value part
+		}
+		return match
+	})
+
 	return content, nil
 }
 
@@ -237,6 +254,8 @@ func findFileVars(content string) []fileVar {
 	return envVars
 }
 
+var regexEnvVarWithDefault = regexp.MustCompile(`([^:}]+):([^}]+)`)
+
 func ensureAcceptFileVars(content string) error {
 
 	fileVars := findFileVars(content)
@@ -247,9 +266,13 @@ func ensureAcceptFileVars(content string) error {
 		}
 
 		envVar := envVar.Name
-		if os.Getenv(envVar) == "" && os.Getenv(envVar+"_POOL") == "" {
+		if !varIsSet(envVar) {
 			return fmt.Errorf("missing required environment variable %q", envVar)
 		}
 	}
 	return nil
 }
+
+func varIsSet(varName string) bool {
+	return os.Getenv(varName) != "" || os.Getenv(varName+"_POOL") != ""
+}