Report each anonymous volume's size and the space freed (issue 1796)

modules/docker/cmd/docker-tools/docker.go

@@ -1232,10 +1232,11 @@ func (c *Client) RemoveAnonymousVolumes(ctx context.Context, a RemoveVolumesAsk)
 	if !a.DryRun && strings.TrimSpace(a.Why) == "" {
 		return nil, fmt.Errorf("why is required when dry_run is false")
 	}
-	all, err := c.Volumes(ctx, false, false)
+	all, err := c.Volumes(ctx, false, true)
 	if err != nil {
 		return nil, err
 	}
+	sizes := map[string]string{}
 	candidates := []string{}
 	skipped := []map[string]any{}
 	skip := func(name, why string) { skipped = append(skipped, map[string]any{"name": name, "why": why}) }
@@ -1252,12 +1253,20 @@ func (c *Client) RemoveAnonymousVolumes(ctx context.Context, a RemoveVolumesAsk)
 			skip(name, "not created before "+a.CreatedBefore.Format(time.RFC3339)+" (created "+fmt.Sprint(v["created"])+")")
 		default:
 			candidates = append(candidates, name)
+			sizes[name] = fmt.Sprint(v["size"])
 		}
 	}
-	answer := map[string]any{"dry_run": a.DryRun, "skipped": skipped,
-		"space_freed": "not reported: docker volume rm names what it removed; docker_disk_usage shows the space"}
+	sum := func(names []string) int64 {
+		var t int64
+		for _, n := range names {
+			t += max(Bytes(sizes[n]), 0)
+		}
+		return t
+	}
+	answer := map[string]any{"dry_run": a.DryRun, "skipped": skipped, "sizes": sizes}
 	if a.DryRun {
 		answer["would_remove"] = candidates
+		answer["would_free_bytes"] = sum(candidates)
 		answer["note"] = "nothing was removed: call again with dry_run false and why to remove them"
 		return answer, nil
 	}
@@ -1271,6 +1280,7 @@ func (c *Client) RemoveAnonymousVolumes(ctx context.Context, a RemoveVolumesAsk)
 	}
 	answer["skipped"] = skipped
 	answer["removed"], answer["count"], answer["why"] = removed, len(removed), a.Why
+	answer["freed_bytes"] = sum(removed)
 	return answer, nil
 }
 

modules/docker/cmd/docker-tools/docker_test.go

@@ -441,6 +441,7 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 {"Name":"old","Driver":"local","CreatedAt":"2026-09-01T00:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
 {"Name":"young","Driver":"local","CreatedAt":"2026-10-04T11:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
 {"Name":"named","Driver":"local","CreatedAt":"2026-01-01T00:00:00Z"}]`}).
+		on("docker system df --verbose", Ran{Stdout: `{"Volumes":[{"Name":"old","Size":"1.5MB"},{"Name":"young","Size":"1kB"}]}`}).
 		on("docker volume rm old", Ran{Stdout: "old\n"})
 	c := client(f, 1000)
 	before := time.Date(2026, 10, 3, 0, 0, 0, 0, time.UTC)
@@ -451,12 +452,15 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 	if f.ran("docker volume rm") || !reflect.DeepEqual(got["would_remove"], []string{"old"}) {
 		t.Fatalf("dry run: %v %+v", got, f.calls)
 	}
+	if got["would_free_bytes"] != int64(1500000) || got["sizes"].(map[string]string)["old"] != "1.5MB" {
+		t.Fatalf("dry run size: %v", got)
+	}
 	skipped := got["skipped"].([]map[string]any)
 	why := map[string]string{}
 	for _, s := range skipped {
 		why[s["name"].(string)] = s["why"].(string)
 	}
-	if len(why) != 3 || why["webdata"] == "" || why["young"] == "" || why["named"] == "" {
+	if len(why) != 3 || !strings.Contains(why["webdata"], "mesh holds") || why["young"] == "" || why["named"] == "" {
 		t.Fatalf("skipped: %v", skipped)
 	}
 	got, err = c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "leftovers", CreatedBefore: &before})
@@ -466,6 +470,9 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 	if !f.ran("docker volume rm old") || got["count"] != 1 || !reflect.DeepEqual(got["removed"], []string{"old"}) {
 		t.Fatalf("removed: %v %+v", got, f.calls)
 	}
+	if got["freed_bytes"] != int64(1500000) {
+		t.Fatalf("freed: %v", got)
+	}
 	for _, c := range f.calls {
 		if len(c.args) > 1 && c.args[0] == "volume" && c.args[1] == "rm" && (len(c.args) != 3 || c.args[2] != "old") {
 			t.Errorf("reached too far: %v", c.args)

modules/docker/cmd/docker-tools/main.go

@@ -291,7 +291,7 @@ func tools(c *Client) []stdio.Tool {
 			Name: "docker_volumes_remove_anonymous",
 			Description: "Remove the leftover anonymous volumes (novox/hq issue 1796): only a volume docker labels anonymous (as docker_volumes says), which no container mounts in any state " +
 				"and so none the mesh holds, and with created_before only one created before it. Every other volume is answered with why it stays; a named volume is data and is never taken, " +
-				"and no volume can be named. Each is removed on its own, never forced; the answer has the count and names removed. Docker does not report the space a removed volume freed. " +
+				"and no volume can be named. Each is removed on its own, never forced; the answer has the count and names removed. The answer has each volume's size and the bytes freed (or, in a dry run, that would be). " +
 				"A dry run by default; dry_run false needs why. Replaces docker volume rm and docker volume prune. (a)",
 			Input: map[string]any{
 				"dry_run":        map[string]any{"type": "boolean", "description": "list only (default true)"},