LDAP: Interpolate env variable expressions in ldap.toml file (#20173)

* LDAP: Interpolate env variable expressions in ldap.toml file

* Removed comment

pkg/services/ldap/settings.go

@@ -2,6 +2,7 @@ package ldap
 
 import (
 	"fmt"
+	"io/ioutil"
 	"sync"
 
 	"github.com/BurntSushi/toml"
@@ -118,7 +119,15 @@ func readConfig(configFile string) (*Config, error) {
 
 	logger.Info("LDAP enabled, reading config file", "file", configFile)
 
-	_, err := toml.DecodeFile(configFile, result)
+	fileBytes, err := ioutil.ReadFile(configFile)
+	if err != nil {
+		return nil, errutil.Wrap("Failed to load LDAP config file", err)
+	}
+
+	// interpolate full toml string (it can contain ENV variables)
+	stringContent := setting.EvalEnvVarExpression(string(fileBytes))
+
+	_, err = toml.Decode(stringContent, result)
 	if err != nil {
 		return nil, errutil.Wrap("Failed to load LDAP config file", err)
 	}

pkg/services/ldap/settings_test.go

@@ -0,0 +1,22 @@
+package ldap
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestReadingLDAPSettings(t *testing.T) {
+	config, err := readConfig("testdata/ldap.toml")
+	assert.Nil(t, err, "No error when reading ldap config")
+	assert.EqualValues(t, "127.0.0.1", config.Servers[0].Host)
+}
+
+func TestReadingLDAPSettingsWithEnvVariable(t *testing.T) {
+	os.Setenv("ENV_PASSWORD", "MySecret")
+
+	config, err := readConfig("testdata/ldap.toml")
+	assert.Nil(t, err, "No error when reading ldap config")
+	assert.EqualValues(t, "MySecret", config.Servers[0].BindPassword)
+}

pkg/services/ldap/testdata/ldap.toml

@@ -0,0 +1,27 @@
+[[servers]]
+host = "127.0.0.1"
+port = 389
+use_ssl = false
+start_tls = false
+ssl_skip_verify = false
+bind_dn = "cn=admin,dc=grafana,dc=org"
+bind_password = '${ENV_PASSWORD}'
+search_filter = "(cn=%s)"
+search_base_dns = ["dc=grafana,dc=org"]
+
+[servers.attributes]
+name = "givenName"
+surname = "sn"
+username = "cn"
+member_of = "memberOf"
+email =  "email"
+
+[[servers.group_mappings]]
+group_dn = "cn=admins,ou=groups,dc=grafana,dc=org"
+org_role = "Admin"
+grafana_admin = true
+
+[[servers.group_mappings]]
+group_dn = "cn=users,ou=groups,dc=grafana,dc=org"
+org_role = "Editor"
+

pkg/setting/setting.go

@@ -412,7 +412,7 @@ func makeAbsolute(path string, root string) string {
 	return filepath.Join(root, path)
 }
 
-func evalEnvVarExpression(value string) string {
+func EvalEnvVarExpression(value string) string {
 	regex := regexp.MustCompile(`\${(\w+)}`)
 	return regex.ReplaceAllStringFunc(value, func(envVar string) string {
 		envVar = strings.TrimPrefix(envVar, "${")
@@ -431,7 +431,7 @@ func evalEnvVarExpression(value string) string {
 func evalConfigValues(file *ini.File) {
 	for _, section := range file.Sections() {
 		for _, key := range section.Keys() {
-			key.SetValue(evalEnvVarExpression(key.Value()))
+			key.SetValue(EvalEnvVarExpression(key.Value()))
 		}
 	}
 }