Docker: support passing additional commandline args to synapse

changelog.d/8390.docker

@@ -0,0 +1 @@
+Added support for passing commandline args to the synapse process. Contributed by @samuel-p.

docker/start.py

@@ -205,36 +205,43 @@ def main(args, environ):
             config_dir, config_path, environ, ownership
         )
 
-    if mode is not None:
-        error("Unknown execution mode '%s'" % (mode,))
+    args = ["python"] + args[1:]
 
-    config_dir = environ.get("SYNAPSE_CONFIG_DIR", "/data")
-    config_path = environ.get("SYNAPSE_CONFIG_PATH", config_dir + "/homeserver.yaml")
+    if "-m" not in args:
+        args = ["-m", synapse_worker] + args
 
-    if not os.path.exists(config_path):
-        if "SYNAPSE_SERVER_NAME" in environ:
-            error(
-                """\
-Config file '%s' does not exist.
+    if not filter(lambda p: p.startswith("--config-path"), args):
+        config_dir = environ.get("SYNAPSE_CONFIG_DIR", "/data")
+        config_path = environ.get(
+            "SYNAPSE_CONFIG_PATH", config_dir + "/homeserver.yaml"
+        )
 
+        if not os.path.exists(config_path):
+            if "SYNAPSE_SERVER_NAME" in environ:
+                error(
+                    """\
+Config file '%s' does not exist.
+
 The synapse docker image no longer supports generating a config file on-the-fly
 based on environment variables. You can migrate to a static config file by
 running with 'migrate_config'. See the README for more details.
 """
+                    % (config_path,)
+                )
+
+            error(
+                "Config file '%s' does not exist. You should either create a new "
+                "config file by running with the `generate` argument (and then edit "
+                "the resulting file before restarting) or specify the path to an "
+                "existing config file with the SYNAPSE_CONFIG_PATH variable."
                 % (config_path,)
             )
 
-        error(
-            "Config file '%s' does not exist. You should either create a new "
-            "config file by running with the `generate` argument (and then edit "
-            "the resulting file before restarting) or specify the path to an "
-            "existing config file with the SYNAPSE_CONFIG_PATH variable."
-            % (config_path,)
-        )
+        if "--config-path=" + config_path not in args:
+            args += ["--config-path", config_path]
 
-    log("Starting synapse with config file " + config_path)
+    log("Starting synapse with args " + " ".join(args))
 
-    args = ["python", "-m", synapse_worker, "--config-path", config_path]
     if ownership is not None:
         args = ["gosu", ownership] + args
         os.execv("/usr/sbin/gosu", args)