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
 }