Feature 57 (config and provisioning): release mesh-controller, the reviewed release branch merged with main, on top of main

cmd/mesh-controller/placement_move.go

@@ -0,0 +1,99 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// movePlacementAnswer is what the move of placement says it did, or would do (issue 736).
+type movePlacementAnswer struct {
+	// DryRun is true when nothing was moved: asked without --confirm.
+	DryRun bool `json:"dry-run"`
+	// Moved is each layer that held a placement key among its settings, and which keys.
+	Moved []inventory.MovedLayer `json:"moved"`
+}
+
+// movePlacementCommand is `move-placement`: the move of placement out of the settings layers (novox/hq ADR 0348
+// clause 11, issue 736), one of the moves of data a release runs once after its delivery (design 57).
+func movePlacementCommand(ctx context.Context, args []string) error {
+	set := flag.NewFlagSet("move-placement", flag.ContinueOnError)
+	asJSON := set.Bool("json", false, "answer as JSON")
+	confirm := set.Bool("confirm", false, "move the keys, rather than only say which layers hold them")
+	f := addHandActFlags(set)
+	positionals, err := parseAround(set, args)
+	if err != nil {
+		return err
+	}
+	if len(positionals) != 0 {
+		return errors.New("move-placement [--json] [--confirm --why <text>]")
+	}
+	if !*confirm && f.given() {
+		return errors.New("move-placement takes --why only with --confirm: without it nothing is moved. Nothing was done")
+	}
+	if *confirm {
+		// A move a person asks for says why, before anything is asked of the store.
+		if err := f.require("move-placement"); err != nil {
+			return err
+		}
+	}
+	open, err := openStores(ctx)
+	if err != nil {
+		return err
+	}
+	defer open.Close()
+	if *confirm {
+		f.record(ctx, "move-placement", nil)
+	}
+	answer, err := runMovePlacement(ctx, open.inventory, *confirm)
+	if err != nil {
+		return err
+	}
+	if *asJSON {
+		encoder := json.NewEncoder(os.Stdout)
+		encoder.SetIndent("", " ")
+		return encoder.Encode(answer)
+	}
+	fmt.Print(describeMovePlacement(answer))
+	return nil
+}
+
+// runMovePlacement is the move against a store: a dry run says what it would move.
+func runMovePlacement(ctx context.Context, inv *inventory.Inventory, apply bool) (movePlacementAnswer, error) {
+	moved, err := inv.MovePlacement(ctx, apply)
+	if err != nil {
+		return movePlacementAnswer{}, err
+	}
+	return movePlacementAnswer{DryRun: !apply, Moved: moved}, nil
+}
+
+// describeMovePlacement says the answer as a person reads it.
+func describeMovePlacement(a movePlacementAnswer) string {
+	if len(a.Moved) == 0 {
+		return "no settings layer holds a placement key: nothing to move\n"
+	}
+	var b strings.Builder
+	verb := "moved"
+	if a.DryRun {
+		verb = "would move"
+	}
+	for _, m := range a.Moved {
+		where := m.Node
+		if where == "" {
+			where = "the whole mesh"
+		}
+		fmt.Fprintf(&b, "%s on %s: %s %s\n", m.Module, where, verb, strings.Join(m.Keys, ", "))
+	}
+	if a.DryRun {
+		fmt.Fprintf(&b, "%d layer(s); nothing was moved — with --confirm --why <text> they are\n", len(a.Moved))
+	} else {
+		fmt.Fprintf(&b, "%d layer(s) moved beside their assignments, each kept whole in its history first\n", len(a.Moved))
+	}
+	return b.String()
+}