feature: basic management service implementation (#44)

* feat: basic management service implementation [FAILING TESTS]

* test: fix healthcheck test

* test: #39 add peer registration endpoint test

* feat: #39 add setup key handling

* feat: #39 add peer management store persistence

* refactor: extract config read/write to the utility package

* refactor: move file contents copy to the utility package

* refactor: use Accounts instead of Users in the Store

* feature: add management server Docker file

* refactor: introduce datadir instead of config

* chore: use filepath.Join to concat filepaths instead of string concat

* refactor: move stop channel to the root

* refactor: move stop channel to the root

* review: fix PR review notes

Co-authored-by: braginini <hello@wiretrustee.com>

util/file.go

@@ -0,0 +1,79 @@
+package util
+
+import (
+	"encoding/json"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// WriteJson writes JSON config object to a file creating parent directories if required
+// The output JSON is pretty-formatted
+func WriteJson(file string, obj interface{}) error {
+
+	configDir := filepath.Dir(file)
+	err := os.MkdirAll(configDir, 0750)
+	if err != nil {
+		return err
+	}
+
+	// make it pretty
+	bs, err := json.MarshalIndent(obj, "", "    ")
+	if err != nil {
+		return err
+	}
+
+	err = ioutil.WriteFile(file, bs, 0600)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// ReadJson reads JSON config file and maps to a provided interface
+func ReadJson(file string, res interface{}) (interface{}, error) {
+
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	bs, err := ioutil.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(bs, &res)
+	if err != nil {
+		return nil, err
+	}
+
+	return res, nil
+}
+
+// CopyFileContents copies contents of the given src file to the dst file
+func CopyFileContents(src, dst string) (err error) {
+	in, err := os.Open(src)
+	if err != nil {
+		return
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return
+	}
+	defer func() {
+		cErr := out.Close()
+		if err == nil {
+			err = cErr
+		}
+	}()
+	if _, err = io.Copy(out, in); err != nil {
+		return
+	}
+	err = out.Sync()
+	return
+}