zrepl wait: poll-based implementation

client/wait.go

@@ -0,0 +1,110 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/kr/pretty"
+	"github.com/pkg/errors"
+	"github.com/spf13/pflag"
+
+	"github.com/zrepl/zrepl/cli"
+	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/daemon"
+	"github.com/zrepl/zrepl/daemon/job"
+)
+
+var waitCmdArgs struct {
+	verbose bool
+	interval time.Duration
+}
+
+var WaitCmd = &cli.Subcommand{
+	Use:   "wait [active JOB INVOCATION_ID WHAT]",
+	Short: "",
+	Run: func(ctx context.Context, subcommand *cli.Subcommand, args []string) error {
+		return runWaitCmd(subcommand.Config(), args)
+	},
+	SetupFlags: func(f *pflag.FlagSet) {
+		f.BoolVarP(&waitCmdArgs.verbose, "verbose", "v", false, "verbose output")
+		f.DurationVarP(&waitCmdArgs.interval, "poll-interval", "i", 100*time.Millisecond, "poll interval")
+	},
+}
+
+func runWaitCmd(config *config.Config, args []string) error {
+
+	httpc, err := controlHttpClient(config.Global.Control.SockPath)
+	if err != nil {
+		return err
+	}
+
+	if args[0] != "active" {
+		panic(args)
+	}
+	args = args[1:]
+
+	jobName := args[0]
+
+	invocationId, err := strconv.ParseUint(args[1], 10, 64)
+	if err != nil {
+		return errors.Wrap(err, "parse invocation id")
+	}
+
+	waitWhat := args[2]
+
+	doneErr := fmt.Errorf("done")
+
+	var pollRequest job.ActiveSidePollRequest
+
+	// updated by subsequent requests
+	pollRequest = job.ActiveSidePollRequest{
+		InvocationId: invocationId,
+		What:         waitWhat,
+	}
+
+	pollOnce := func() error {
+		var res job.ActiveSidePollResponse
+		if waitCmdArgs.verbose {
+			pretty.Println("making poll request", pollRequest)
+		}
+		err = jsonRequestResponse(httpc, daemon.ControlJobEndpointPollActive,
+			struct {
+				Job string
+				job.ActiveSidePollRequest
+			}{
+				Job:                   jobName,
+				ActiveSidePollRequest: pollRequest,
+			},
+			&res,
+		)
+		if err != nil {
+			return err
+		}
+
+		if waitCmdArgs.verbose {
+			pretty.Println("got poll response", res)
+		}
+
+		if res.Done {
+			return doneErr
+		}
+
+		pollRequest.InvocationId = res.InvocationId
+
+		return nil
+	}
+
+	t := time.NewTicker(waitCmdArgs.interval)
+	for range t.C {
+		err := pollOnce()
+		if err == doneErr {
+			return nil
+		} else if err != nil {
+			return err
+		}
+	}
+
+	return err
+}