fix: pick correct broadcast adapter on Fly

config/presets.go

@@ -67,6 +67,8 @@ func (c *Config) loadFlyPreset(defaults *Config) error {
 		return errors.New("FLY_APP_NAME env is missing")
 	}
 
+	redisEnabled := (c.Redis.URL != defaults.Redis.URL)
+
 	// Obtain cluster info
 	cluster, err := fly.Cluster(appName)
 
@@ -107,12 +109,16 @@ func (c *Config) loadFlyPreset(defaults *Config) error {
 	// Enable embedded NATS by default unless another adapter is set for PubSub
 	// or Redis URL is provided
 	if c.PubSubAdapter == defaults.PubSubAdapter {
-		if c.Redis.URL != defaults.Redis.URL {
+		if redisEnabled {
 			c.PubSubAdapter = "redis"
 		}
 	}
 
 	if multiNode {
+		if !redisEnabled && c.BroadcastAdapter == defaults.BroadcastAdapter {
+			c.BroadcastAdapter = "http,nats"
+		}
+
 		if c.PubSubAdapter == defaults.PubSubAdapter {
 			c.PubSubAdapter = "nats"
 		}
@@ -134,6 +140,10 @@ func (c *Config) loadFlyPreset(defaults *Config) error {
 	if singleNode {
 		log.WithField("context", "config").Infof("Discovered a single node cluster -> enabling in-memory broker")
 		c.BrokerAdapter = "memory"
+
+		if !redisEnabled && c.BroadcastAdapter == defaults.BroadcastAdapter {
+			c.BroadcastAdapter = "http"
+		}
 	}
 
 	if rpcName, ok := os.LookupEnv("ANYCABLE_FLY_RPC_APP_NAME"); ok {

config/presets_test.go

@@ -77,6 +77,7 @@ func TestFlyPresets_when_single_vm_discovered(t *testing.T) {
 	// In-memory broker is good enough for single node, no pub/sub needed
 	assert.Equal(t, false, config.EmbedNats)
 	assert.Equal(t, "", config.PubSubAdapter)
+	assert.Equal(t, "http", config.BroadcastAdapter)
 	assert.Equal(t, "memory", config.BrokerAdapter)
 	assert.Equal(t, "nats://0.0.0.0:4222", config.EmbeddedNats.ServiceAddr)
 }
@@ -105,6 +106,7 @@ func TestFlyPresets_when_two_vms_discovered(t *testing.T) {
 	assert.Equal(t, "0.0.0.0", config.Host)
 	assert.Equal(t, 8989, config.Port)
 	assert.Equal(t, 8989, config.HTTPBroadcast.Port)
+	assert.Equal(t, "http,nats", config.BroadcastAdapter)
 	assert.Equal(t, true, config.EmbedNats)
 	assert.Equal(t, "nats", config.PubSubAdapter)
 	// We do not enable broker by default, since it requires at least 3 nodes or exactly 1
@@ -139,6 +141,7 @@ func TestFlyPresets_when_three_vms_discovered(t *testing.T) {
 	assert.Equal(t, "0.0.0.0", config.Host)
 	assert.Equal(t, 8989, config.Port)
 	assert.Equal(t, 8989, config.HTTPBroadcast.Port)
+	assert.Equal(t, "http,nats", config.BroadcastAdapter)
 	assert.Equal(t, true, config.EmbedNats)
 	assert.Equal(t, "nats", config.PubSubAdapter)
 	assert.Equal(t, "nats", config.BrokerAdapter)
@@ -173,6 +176,7 @@ func TestFlyPresets_when_three_vms_from_different_regions(t *testing.T) {
 	assert.Equal(t, 8989, config.Port)
 	assert.Equal(t, 8989, config.HTTPBroadcast.Port)
 	assert.Equal(t, true, config.EmbedNats)
+	assert.Equal(t, "http,nats", config.BroadcastAdapter)
 	assert.Equal(t, "nats", config.PubSubAdapter)
 	// Currently, we do not enable broker for multi-region setup; we need to figure this out later
 	assert.Equal(t, "", config.BrokerAdapter)

docs/configuration.md

@@ -131,6 +131,7 @@ The preset provide the following defaults:
 
 - `host`: "0.0.0.0"
 - `http_broadcast_port`: `$PORT` (set to the same value as the main HTTP port).
+- `broadcast_adapter`: "http" (unless Redis is configured)
 - `enats_server_addr`: "nats://0.0.0.0:4222"
 - `enats_cluster_addr`: "nats://0.0.0.0:5222"
 - `enats_cluster_name`: "\<FLY_APP_NAME\>-\<FLY_REGION\>-cluster"