Review comments

src/github.com/matrix-org/dendrite/common/config/config.go

@@ -44,17 +44,17 @@ type Dendrite struct {
 		ServerName gomatrixserverlib.ServerName `yaml:"server_name"`
 		// Path to the private key which will be used to sign requests and events.
 		PrivateKeyPath Path `yaml:"private_key"`
+		// The private key which will be used to sign requests and events.
+		PrivateKey ed25519.PrivateKey `yaml:"-"`
+		// An arbitrary string used to uniquely identify the PrivateKey. Must start with the
+		// prefix "ed25519:".
+		KeyID gomatrixserverlib.KeyID `yaml:"-"`
 		// List of paths to X509 certificates used by the external federation listeners.
 		// These are used to calculate the TLS fingerprints to publish for this server.
 		// Other matrix servers talking to this server will expect the x509 certificate
 		// to match one of these certificates.
 		// The certificates should be in PEM format.
 		FederationCertificatePaths []Path `yaml:"federation_certificates"`
-		// The private key which will be used to sign requests and events.
-		PrivateKey ed25519.PrivateKey `yaml:"-"`
-		// An arbitrary string used to uniquely identify the PrivateKey. Must start with the
-		// prefix "ed25519:".
-		KeyID gomatrixserverlib.KeyID `yaml:"-"`
 		// A list of SHA256 TLS fingerprints for the X509 certificates used by the
 		// federation listener for this server.
 		TLSFingerPrints []gomatrixserverlib.TLSFingerprint `yaml:"-"`
@@ -62,6 +62,7 @@ type Dendrite struct {
 		// Increasing this number will reduce the number of requests made by remote servers
 		// for our key, but increases the period a compromised key will be considered valid
 		// by remote servers.
+		// Defaults to 24 hours.
 		KeyValidityPeriod time.Duration `yaml:"key_validity_period"`
 	} `yaml:"matrix"`
 
@@ -98,12 +99,24 @@ type Dendrite struct {
 
 	// Postgres Config
 	Database struct {
-		MediaServer DataSource `yaml:"media_server"`
-		Account     DataSource `yaml:"account"`
-		Device      DataSource `yaml:"device"`
-		ServerKey   DataSource `yaml:"server_key"`
-		SyncServer  DataSource `yaml:"sync_server"`
-		RoomServer  DataSource `yaml:"room_server"`
+		// The Account database stores the login details and account information
+		// for local users. It is accessed by the ClientAPI.
+		Account DataSource `yaml:"account"`
+		// The Device database stores session information for the devices of logged
+		// in local users. It is accessed by the ClientAPI, the MediaAPI and the SyncAPI.
+		Device DataSource `yaml:"device"`
+		// The MediaAPI database stores information about files uploaded and downloaded
+		// by local users. It is only accessed by the MediaAPI.
+		MediaAPI DataSource `yaml:"media_api"`
+		// The ServerKey database caches the public keys of remote servers.
+		// It may be accessed by the FederationAPI, the ClientAPI, and the MediaAPI.
+		ServerKey DataSource `yaml:"server_key"`
+		// The SyncAPI stores information used by the SyncAPI server.
+		// It is only accessed by the SyncAPI server.
+		SyncAPI DataSource `yaml:"sync_api"`
+		// The RoomServer database stores information about matrix rooms.
+		// It is only accessed by the RoomServer.
+		RoomServer DataSource `yaml:"room_server"`
 	} `yaml:"database"`
 
 	// The internal addresses the components will listen on.
@@ -150,11 +163,13 @@ func Load(configPath string) (*Dendrite, error) {
 	if err != nil {
 		return nil, err
 	}
-	configDirPath, err := filepath.Abs(".")
+	basePath, err := filepath.Abs(".")
 	if err != nil {
 		return nil, err
 	}
-	return loadConfig(configDirPath, configData, ioutil.ReadFile)
+	// Pass the current working directory and ioutil.ReadFile so that they can
+	// be mocked in the tests
+	return loadConfig(basePath, configData, ioutil.ReadFile)
 }
 
 // An Error indicates a problem parsing the config.
@@ -274,11 +289,11 @@ func (config *Dendrite) check() error {
 	checkNotZero("kafka.addresses", int64(len(config.Kafka.Addresses)))
 	checkNotEmpty("kafka.topics.input_room_event", string(config.Kafka.Topics.InputRoomEvent))
 	checkNotEmpty("kafka.topics.output_room_event", string(config.Kafka.Topics.OutputRoomEvent))
-	checkNotEmpty("database.media_server", string(config.Database.MediaServer))
 	checkNotEmpty("database.account", string(config.Database.Account))
 	checkNotEmpty("database.device", string(config.Database.Device))
 	checkNotEmpty("database.server_key", string(config.Database.ServerKey))
-	checkNotEmpty("database.sync_server", string(config.Database.SyncServer))
+	checkNotEmpty("database.media_api", string(config.Database.MediaAPI))
+	checkNotEmpty("database.sync_api", string(config.Database.SyncAPI))
 	checkNotEmpty("database.room_server", string(config.Database.RoomServer))
 	checkNotEmpty("listen.media_api", string(config.Listen.MediaAPI))
 	checkNotEmpty("listen.client_api", string(config.Listen.ClientAPI))

src/github.com/matrix-org/dendrite/common/config/config_test.go

@@ -45,11 +45,11 @@ kafka:
     input_room_event: input.room
     output_room_event: output.room
 database:
-  media_server: "postgresql:///media_server"
+  media_api: "postgresql:///media_api"
   account: "postgresql:///account"
   device: "postgresql:///device"
   server_key: "postgresql:///server_keys"
-  sync_server: "postgresql:///sync_server"
+  sync_api: "postgresql:///syn_api"
   room_server: "postgresql:///room_server"
 listen:
   room_server: "localhost:7770"