Merge pull request 'A cross-node module reaches the broker by the hub's overlay name' (#27) from multi-node/broker-reaches-over-overlay into main

cmd/mesh-controller/build.go

@@ -216,6 +216,11 @@ func builderCommand(ctx context.Context, args []string) error {
 		}
 		defer inv.Close()
 
+		brokerAddr, err := brokerReachableAt(ctx, inv, known, *forNode)
+		if err != nil {
+			return err
+		}
+
 		// The URL and what verifies the broker, together. A mesh's broker presents a certificate
 		// of the mesh's own, which is in no public trust store — so a URL on its own reaches only
 		// a broker somebody else vouches for, and the connection fails at TLS with an error about
@@ -228,7 +233,7 @@ func builderCommand(ctx context.Context, args []string) error {
 			URL         string `json:"url"`
 			Fingerprint string `json:"fingerprint,omitempty"`
 		}{
-			URL:         fmt.Sprintf("amqps://%s:%s@%s/", name, password, known.Address),
+			URL:         fmt.Sprintf("amqps://%s:%s@%s/", name, password, brokerAddr),
 			Fingerprint: known.Fingerprint,
 		})
 		if err != nil {

cmd/mesh-controller/modules.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"net"
 	"os"
 	"sort"
 	"strings"
@@ -283,6 +284,10 @@ func moduleCommand(ctx context.Context, args []string) error {
 		if err != nil {
 			return fmt.Errorf("cannot deliver a credential without knowing where the broker is: %w", err)
 		}
+		brokerAddr, err := brokerReachableAt(ctx, inv, known, *forNode)
+		if err != nil {
+			return err
+		}
 		// The URL and what verifies the broker, together — a mesh's broker presents its own
 		// certificate, in no public trust store, so a URL alone fails at TLS (as `builder issue`).
 		held, err := json.Marshal(struct {
@@ -291,7 +296,7 @@ func moduleCommand(ctx context.Context, args []string) error {
 			Node        string `json:"node"`
 			Module      string `json:"module"`
 		}{
-			URL:         fmt.Sprintf("amqps://%s:%s@%s/", account, password, known.Address),
+			URL:         fmt.Sprintf("amqps://%s:%s@%s/", account, password, brokerAddr),
 			Fingerprint: known.Fingerprint,
 			// The node and module the account is for, so the runtime names its queue as the mesh
 			// scoped it (<node>.<module>.events) without a manifest having to interpolate a node.
@@ -461,3 +466,37 @@ func pinCommand(ctx context.Context, args []string, setting bool) error {
 	fmt.Printf("  run `push %s` to send it\n", args[0])
 	return nil
 }
+
+// brokerReachableAt is the broker's address as the given node can reach it.
+//
+// The genesis address (MESH_BROKER_ADDRESS) is the broker's public endpoint — reachable from the
+// control-node itself, but not routed to another node, whose firewall admits only the overlay
+// (from:mesh). The foundation, and so the broker, sits on the control-node, which is the overlay
+// hub; a node that is on the overlay reaches the broker by the hub's `.internal` name, which the
+// firewall admits and every node resolves. A node not yet on the overlay — at genesis, before any
+// `overlay place`, which is when the builder's account is issued — keeps the genesis address it
+// was given, so nothing about bring-up changes. This is issue 055.
+func brokerReachableAt(ctx context.Context, inv *inventory.Inventory, known broker.Broker, node string) (string, error) {
+	overlays, err := inv.Overlays(ctx)
+	if err != nil {
+		return "", err
+	}
+	var hub string
+	onOverlay := false
+	for _, o := range overlays {
+		if o.Hub && o.Address != "" {
+			hub = o.Name
+		}
+		if o.Name == node && o.Address != "" {
+			onOverlay = true
+		}
+	}
+	if hub == "" || !onOverlay {
+		return known.Address, nil
+	}
+	_, port, err := net.SplitHostPort(known.Address)
+	if err != nil {
+		return known.Address, nil
+	}
+	return net.JoinHostPort(overlay.InternalName(hub), port), nil
+}