Init command JSON output

changelog/unreleased/issue-3124

@@ -0,0 +1,7 @@
+Enhancement: Support json output for the `init` command
+
+The `init` command ignored the `--json` flag. It now outputs a JSON message if
+the repository was created successfully.
+
+https://github.com/restic/restic/issues/3124
+https://github.com/restic/restic/pull/3132

cmd/restic/cmd_init.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/json"
 	"strconv"
 
 	"github.com/restic/chunker"
@@ -100,11 +101,21 @@ func runInit(ctx context.Context, opts InitOptions, gopts GlobalOptions, args []
 		return errors.Fatalf("create key in repository at %s failed: %v\n", location.StripPassword(gopts.Repo), err)
 	}
 
-	Verbosef("created restic repository %v at %s\n", s.Config().ID[:10], location.StripPassword(gopts.Repo))
-	Verbosef("\n")
-	Verbosef("Please note that knowledge of your password is required to access\n")
-	Verbosef("the repository. Losing your password means that your data is\n")
-	Verbosef("irrecoverably lost.\n")
+	if !gopts.JSON {
+		Verbosef("created restic repository %v at %s\n", s.Config().ID[:10], location.StripPassword(gopts.Repo))
+		Verbosef("\n")
+		Verbosef("Please note that knowledge of your password is required to access\n")
+		Verbosef("the repository. Losing your password means that your data is\n")
+		Verbosef("irrecoverably lost.\n")
+
+	} else {
+		status := initSuccess{
+			MessageType: "initialized",
+			ID:          s.Config().ID,
+			Repository:  location.StripPassword(gopts.Repo),
+		}
+		return json.NewEncoder(gopts.stdout).Encode(status)
+	}
 
 	return nil
 }
@@ -130,3 +141,9 @@ func maybeReadChunkerPolynomial(ctx context.Context, opts InitOptions, gopts Glo
 	}
 	return nil, nil
 }
+
+type initSuccess struct {
+	MessageType string `json:"message_type"` // "initialized"
+	ID          string `json:"id"`
+	Repository  string `json:"repository"`
+}