Prefix-defined Kafka topics (#1254)

* Prefix-defined Kafka topics

* Fix current state server test

2 files changed, 52 insertions, 54 deletions

diff --git a/internal/config/config_global.go b/internal/config/config_global.go
index 9456dd3f..785a8033 100644
--- a/internal/config/config_global.go
+++ b/internal/config/config_global.go
@@ -60,60 +60,6 @@ func (c *Global) Verify(configErrs *ConfigErrors, isMonolith bool) {
 	c.Metrics.Verify(configErrs, isMonolith)
 }
 
-type Kafka struct {
-	// A list of kafka addresses to connect to.
-	Addresses []string `yaml:"addresses"`
-	// Whether to use naffka instead of kafka.
-	// Naffka can only be used when running dendrite as a single monolithic server.
-	// Kafka can be used both with a monolithic server and when running the
-	// components as separate servers.
-	UseNaffka bool `yaml:"use_naffka"`
-	// The Naffka database is used internally by the naffka library, if used.
-	Database DatabaseOptions `yaml:"naffka_database"`
-	// The names of the topics to use when reading and writing from kafka.
-	Topics struct {
-		// Topic for roomserver/api.OutputRoomEvent events.
-		OutputRoomEvent Topic `yaml:"output_room_event"`
-		// Topic for sending account data from client API to sync API
-		OutputClientData Topic `yaml:"output_client_data"`
-		// Topic for eduserver/api.OutputTypingEvent events.
-		OutputTypingEvent Topic `yaml:"output_typing_event"`
-		// Topic for eduserver/api.OutputSendToDeviceEvent events.
-		OutputSendToDeviceEvent Topic `yaml:"output_send_to_device_event"`
-		// Topic for keyserver when new device keys are added.
-		OutputKeyChangeEvent Topic `yaml:"output_key_change_event"`
-	}
-}
-
-func (c *Kafka) Defaults() {
-	c.UseNaffka = true
-	c.Database.Defaults()
-	c.Database.ConnectionString = DataSource("file:naffka.db")
-	c.Topics.OutputRoomEvent = "OutputRoomEventTopic"
-	c.Topics.OutputClientData = "OutputClientDataTopic"
-	c.Topics.OutputTypingEvent = "OutputTypingEventTopic"
-	c.Topics.OutputSendToDeviceEvent = "OutputSendToDeviceEventTopic"
-	c.Topics.OutputKeyChangeEvent = "OutputKeyChangeEventTopic"
-}
-
-func (c *Kafka) Verify(configErrs *ConfigErrors, isMonolith bool) {
-	if c.UseNaffka {
-		if !isMonolith {
-			configErrs.Add("naffka can only be used in a monolithic server")
-		}
-		checkNotEmpty(configErrs, "global.kafka.database.connection_string", string(c.Database.ConnectionString))
-	} else {
-		// If we aren't using naffka then we need to have at least one kafka
-		// server to talk to.
-		checkNotZero(configErrs, "global.kafka.addresses", int64(len(c.Addresses)))
-	}
-	checkNotEmpty(configErrs, "global.kafka.topics.output_room_event", string(c.Topics.OutputRoomEvent))
-	checkNotEmpty(configErrs, "global.kafka.topics.output_client_data", string(c.Topics.OutputClientData))
-	checkNotEmpty(configErrs, "global.kafka.topics.output_typing_event", string(c.Topics.OutputTypingEvent))
-	checkNotEmpty(configErrs, "global.kafka.topics.output_send_to_device_event", string(c.Topics.OutputSendToDeviceEvent))
-	checkNotEmpty(configErrs, "global.kafka.topics.output_key_change_event", string(c.Topics.OutputKeyChangeEvent))
-}
-
 // The configuration to use for Prometheus metrics
 type Metrics struct {
 	// Whether or not the metrics are enabled
diff --git a/internal/config/config_kafka.go b/internal/config/config_kafka.go
new file mode 100644
index 00000000..43a27cf2
--- /dev/null
+++ b/internal/config/config_kafka.go
@@ -0,0 +1,52 @@
+package config
+
+import "fmt"
+
+// Defined Kafka topics.
+const (
+	TopicOutputTypingEvent       = "OutputTypingEvent"
+	TopicOutputSendToDeviceEvent = "OutputSendToDeviceEvent"
+	TopicOutputKeyChangeEvent    = "OutputKeyChangeEvent"
+	TopicOutputRoomEvent         = "OutputRoomEvent"
+	TopicOutputClientData        = "OutputClientData"
+)
+
+type Kafka struct {
+	// A list of kafka addresses to connect to.
+	Addresses []string `yaml:"addresses"`
+	// Whether to use naffka instead of kafka.
+	// Naffka can only be used when running dendrite as a single monolithic server.
+	// Kafka can be used both with a monolithic server and when running the
+	// components as separate servers.
+	UseNaffka bool `yaml:"use_naffka"`
+	// The Naffka database is used internally by the naffka library, if used.
+	Database DatabaseOptions `yaml:"naffka_database"`
+	// The prefix to use for Kafka topic names for this homeserver - really only
+	// useful if running more than one Dendrite on the same Kafka deployment.
+	TopicPrefix string `yaml:"topic_prefix"`
+}
+
+func (k *Kafka) TopicFor(name string) string {
+	return fmt.Sprintf("%s%s", k.TopicPrefix, name)
+}
+
+func (c *Kafka) Defaults() {
+	c.UseNaffka = true
+	c.Database.Defaults()
+	c.Database.ConnectionString = DataSource("file:naffka.db")
+	c.TopicPrefix = "Dendrite"
+}
+
+func (c *Kafka) Verify(configErrs *ConfigErrors, isMonolith bool) {
+	if c.UseNaffka {
+		if !isMonolith {
+			configErrs.Add("naffka can only be used in a monolithic server")
+		}
+		checkNotEmpty(configErrs, "global.kafka.database.connection_string", string(c.Database.ConnectionString))
+	} else {
+		// If we aren't using naffka then we need to have at least one kafka
+		// server to talk to.
+		checkNotZero(configErrs, "global.kafka.addresses", int64(len(c.Addresses)))
+	}
+	checkNotEmpty(configErrs, "global.kafka.topic_prefix", string(c.TopicPrefix))
+}