Keep assignments in the assignments bucket and move the rows there at start (issue 1093)

Once chain_moved records the kind, Assign, Unassign and Assigned write and read the keys <node>.<module>, and every join of the store that read assignments is made from the bucket: where a module runs, what is behind, what a machine awaits, a given value due for replacement, taking a module, and whether a module may be forgotten (refused while a standing assignment names it). An unassignment ends the key with a marker and keeps its earlier values, as it removed the row; no ended or pending mark is written yet. The generation rises with each change, and a seat held by an assignment goes with it: the foreign key from seat_holding is dropped by migration 0104 and the controller says both. The provisioner's plan is kept in the values by a pass of the tick that writes that one field by compare-and-set; the assignment-changed event is said from what the bucket holds, whoever wrote it. The start moves the rows with what each machine was last sent, keeping a plan the mirror put in a value.

internal/inventory/given_test.go

@@ -7,8 +7,10 @@ import (
 	"errors"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/novox/mesh-controller/internal/catalogue"
+	"github.com/novox/mesh-controller/internal/chain"
 )
 
 // A module with one secret of each kind the rule tells apart (novox/hq ADR 0228), assigned to the
@@ -36,8 +38,9 @@ func assign(t *testing.T, inv *Inventory, ctx context.Context, node, module stri
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, err := inv.store.Pool().Exec(ctx,
-		`insert into assignment (node, module) values ($1, $2) on conflict do nothing`, n.ID, module); err != nil {
+	// Written as the fixture it is, past the checks Assign makes: the assignment on the bus.
+	if _, err := inv.chain.Assignments.Create(ctx, assignmentKey(n.Name, module),
+		chain.Assignment{Node: n.Name, Module: module, Assigned: time.Now().UTC()}); err != nil && !errors.Is(err, chain.ErrExists) {
 		t.Fatal(err)
 	}
 }