Add support to envsub go management configurations

management/cmd/management.go

@@ -475,7 +475,7 @@ func handlerFunc(gRPCHandler *grpc.Server, httpHandler http.Handler) http.Handle
 
 func loadMgmtConfig(ctx context.Context, mgmtConfigPath string) (*server.Config, error) {
  loadedConfig := &server.Config{}
- _, err := util.ReadJson(mgmtConfigPath, loadedConfig)
+ _, err := util.ReadJsonWithEnvSub(mgmtConfigPath, loadedConfig)
  if err != nil {
  return nil, err
  }

util/file.go

@@ -1,11 +1,15 @@
 package util
 
 import (
+ "bytes"
  "context"
  "encoding/json"
+ "fmt"
  "io"
  "os"
  "path/filepath"
+ "strings"
+ "text/template"
 
  log "github.com/sirupsen/logrus"
 )
@@ -160,6 +164,55 @@ func ReadJson(file string, res interface{}) (interface{}, error) {
  return res, nil
 }
 
+// ReadJsonWithEnvSub reads JSON config file and maps to a provided interface with environment variable substitution
+func ReadJsonWithEnvSub(file string, res interface{}) (interface{}, error) {
+ envVars := getEnvMap()
+
+ f, err := os.Open(file)
+ if err != nil {
+ return nil, err
+ }
+ defer f.Close()
+
+ bs, err := io.ReadAll(f)
+ if err != nil {
+ return nil, err
+ }
+
+ t, err := template.New("").Parse(string(bs))
+ if err != nil {
+ return nil, fmt.Errorf("error parsing template: %v", err)
+ }
+
+ var output bytes.Buffer
+ // Execute the template, substituting environment variables
+ err = t.Execute(&output, envVars)
+ if err != nil {
+ return nil, fmt.Errorf("error executing template: %v", err)
+ }
+
+ err = json.Unmarshal(output.Bytes(), &res)
+ if err != nil {
+ return nil, fmt.Errorf("failed parsing Json file after template was executed, err: %v", err)
+ }
+
+ return res, nil
+}
+
+// getEnvMap Convert the output of os.Environ() to a map
+func getEnvMap() map[string]string {
+ envMap := make(map[string]string)
+
+ for _, env := range os.Environ() {
+ parts := strings.SplitN(env, "=", 2)
+ if len(parts) == 2 {
+ envMap[parts[0]] = parts[1]
+ }
+ }
+
+ return envMap
+}
+
 // CopyFileContents copies contents of the given src file to the dst file
 func CopyFileContents(src, dst string) (err error) {
  in, err := os.Open(src)

util/file_suite_test.go

@@ -0,0 +1,126 @@
+package util_test
+
+import (
+ "crypto/md5"
+ "encoding/hex"
+ "io"
+ "os"
+
+ . "github.com/onsi/ginkgo"
+ . "github.com/onsi/gomega"
+
+ "github.com/netbirdio/netbird/util"
+)
+
+var _ = Describe("Client", func() {
+
+ var (
+ tmpDir string
+ )
+
+ type TestConfig struct {
+ SomeMap map[string]string
+ SomeArray []string
+ SomeField int
+ }
+
+ BeforeEach(func() {
+ var err error
+ tmpDir, err = os.MkdirTemp("", "wiretrustee_util_test_tmp_*")
+ Expect(err).NotTo(HaveOccurred())
+ })
+
+ AfterEach(func() {
+ err := os.RemoveAll(tmpDir)
+ Expect(err).NotTo(HaveOccurred())
+ })
+
+ Describe("Config", func() {
+ Context("in JSON format", func() {
+ It("should be written and read successfully", func() {
+
+ m := make(map[string]string)
+ m["key1"] = "value1"
+ m["key2"] = "value2"
+
+ arr := []string{"value1", "value2"}
+
+ written := &TestConfig{
+ SomeMap: m,
+ SomeArray: arr,
+ SomeField: 99,
+ }
+
+ err := util.WriteJson(tmpDir+"/testconfig.json", written)
+ Expect(err).NotTo(HaveOccurred())
+
+ read, err := util.ReadJson(tmpDir+"/testconfig.json", &TestConfig{})
+ Expect(err).NotTo(HaveOccurred())
+ Expect(read).NotTo(BeNil())
+ Expect(read.(*TestConfig).SomeMap["key1"]).To(BeEquivalentTo(written.SomeMap["key1"]))
+ Expect(read.(*TestConfig).SomeMap["key2"]).To(BeEquivalentTo(written.SomeMap["key2"]))
+ Expect(read.(*TestConfig).SomeArray).To(ContainElements(arr))
+ Expect(read.(*TestConfig).SomeField).To(BeEquivalentTo(written.SomeField))
+
+ })
+ })
+ })
+
+ Describe("Copying file contents", func() {
+ Context("from one file to another", func() {
+ It("should be successful", func() {
+
+ src := tmpDir + "/copytest_src"
+ dst := tmpDir + "/copytest_dst"
+
+ err := util.WriteJson(src, []string{"1", "2", "3"})
+ Expect(err).NotTo(HaveOccurred())
+
+ err = util.CopyFileContents(src, dst)
+ Expect(err).NotTo(HaveOccurred())
+
+ hashSrc := md5.New()
+ hashDst := md5.New()
+
+ srcFile, err := os.Open(src)
+ Expect(err).NotTo(HaveOccurred())
+
+ dstFile, err := os.Open(dst)
+ Expect(err).NotTo(HaveOccurred())
+
+ _, err = io.Copy(hashSrc, srcFile)
+ Expect(err).NotTo(HaveOccurred())
+
+ _, err = io.Copy(hashDst, dstFile)
+ Expect(err).NotTo(HaveOccurred())
+
+ err = srcFile.Close()
+ Expect(err).NotTo(HaveOccurred())
+
+ err = dstFile.Close()
+ Expect(err).NotTo(HaveOccurred())
+
+ Expect(hex.EncodeToString(hashSrc.Sum(nil)[:16])).To(BeEquivalentTo(hex.EncodeToString(hashDst.Sum(nil)[:16])))
+ })
+ })
+ })
+
+ Describe("Handle config file without full path", func() {
+ Context("config file handling", func() {
+ It("should be successful", func() {
+ written := &TestConfig{
+ SomeField: 123,
+ }
+ cfgFile := "test_cfg.json"
+ defer os.Remove(cfgFile)
+
+ err := util.WriteJson(cfgFile, written)
+ Expect(err).NotTo(HaveOccurred())
+
+ read, err := util.ReadJson(cfgFile, &TestConfig{})
+ Expect(err).NotTo(HaveOccurred())
+ Expect(read).NotTo(BeNil())
+ })
+ })
+ })
+})