Strip newlines when reading environment variables from _FILE suffixed files. (#872)

platform/config/env/env.go

@@ -159,5 +159,5 @@ func GetOrFile(envVar string) string {
 		return ""
 	}
 
-	return string(fileContents)
+	return strings.TrimSuffix(string(fileContents), "\n")
 }

platform/config/env/env_test.go

@@ -289,6 +289,23 @@ func TestGetOrFile_ReadsFiles(t *testing.T) {
 	varEnvFileName := "TEST_LEGO_ENV_VAR_FILE"
 	varEnvName := "TEST_LEGO_ENV_VAR"
 
+	testCases := []struct {
+		desc        string
+		fileContent []byte
+	}{
+		{
+			desc:        "simple",
+			fileContent: []byte("lego_file"),
+		},
+		{
+			desc:        "with an empty last line",
+			fileContent: []byte("lego_file\n"),
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+
 			err := os.Unsetenv(varEnvFileName)
 			require.NoError(t, err)
 			err = os.Unsetenv(varEnvName)
@@ -298,7 +315,7 @@ func TestGetOrFile_ReadsFiles(t *testing.T) {
 			require.NoError(t, err)
 			defer os.Remove(file.Name())
 
-	err = ioutil.WriteFile(file.Name(), []byte("lego_file"), 0644)
+			err = ioutil.WriteFile(file.Name(), []byte("lego_file\n"), 0644)
 			require.NoError(t, err)
 
 			err = os.Setenv(varEnvFileName, file.Name())
@@ -308,6 +325,8 @@ func TestGetOrFile_ReadsFiles(t *testing.T) {
 			value := GetOrFile(varEnvName)
 
 			assert.Equal(t, "lego_file", value)
+		})
+	}
 }
 
 func TestGetOrFile_PrefersEnvVars(t *testing.T) {