WIP rewrite the daemon

cmd subdir does not build on purpose, it's only left in tree to grab old
code and move it to github.com/zrepl/zrepl/daemon

wakeup.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"github.com/pkg/errors"
+	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/daemon"
+	"io"
+	"net"
+	"net/http"
+)
+
+func RunWakeup(config config.Config, args []string) error {
+	if len(args) != 1 {
+		return errors.Errorf("Expected 1 argument: job")
+	}
+
+	httpc, err := controlHttpClient(config.Global.Control.SockPath)
+	if err != nil {
+		return err
+	}
+
+	err = jsonRequestResponse(httpc, daemon.ControlJobEndpointWakeup,
+		struct {
+			Name string
+		}{
+			Name: args[0],
+		},
+		struct{}{},
+	)
+	return err
+}
+
+func controlHttpClient(sockpath string) (client http.Client, err error) {
+	return http.Client{
+		Transport: &http.Transport{
+			DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+				return net.Dial("unix", sockpath)
+			},
+		},
+	}, nil
+}
+
+func jsonRequestResponse(c http.Client, endpoint string, req interface{}, res interface{}) error {
+	var buf bytes.Buffer
+	encodeErr := json.NewEncoder(&buf).Encode(req)
+	if encodeErr != nil {
+		return encodeErr
+	}
+
+	resp, err := c.Post("http://unix"+endpoint, "application/json", &buf)
+	if err != nil {
+		return err
+	} else if resp.StatusCode != http.StatusOK {
+		var msg bytes.Buffer
+		io.CopyN(&msg, resp.Body, 4096)
+		return errors.Errorf("%s", msg.String())
+	}
+
+	decodeError := json.NewDecoder(resp.Body).Decode(&res)
+	if decodeError != nil {
+		return decodeError
+	}
+
+	return nil
+}