Config templating (#5900)

Template config files

* Imagine a system composed entirely of x, y, z etc and the basic operations..

Wait George, why XOR? Why not just neq?

George: Eh, I didn't think of that..

Co-Authored-By: Erik Johnston <erik@matrix.org>

Author: JorikSchellekens

changelog.d/5900.feature

@@ -0,0 +1 @@
+Add support for config templating.

docs/sample_config.yaml

@@ -205,9 +205,9 @@ listeners:
   #
   - port: 8008
     tls: false
-    bind_addresses: ['::1', '127.0.0.1']
     type: http
     x_forwarded: true
+    bind_addresses: ['::1', '127.0.0.1']
 
     resources:
       - names: [client, federation]
@@ -392,10 +392,10 @@ listeners:
 #    permission to listen on port 80.
 #
 acme:
-    # ACME support is disabled by default. Uncomment the following line
-    # (and tls_certificate_path and tls_private_key_path above) to enable it.
+    # ACME support is disabled by default. Set this to `true` and uncomment
+    # tls_certificate_path and tls_private_key_path above to enable it.
     #
-    #enabled: true
+    enabled: False
 
     # Endpoint to use to request certificates. If you only want to test,
     # use Let's Encrypt's staging url:
@@ -406,17 +406,17 @@ acme:
     # Port number to listen on for the HTTP-01 challenge. Change this if
     # you are forwarding connections through Apache/Nginx/etc.
     #
-    #port: 80
+    port: 80
 
     # Local addresses to listen on for incoming connections.
     # Again, you may want to change this if you are forwarding connections
     # through Apache/Nginx/etc.
     #
-    #bind_addresses: ['::', '0.0.0.0']
+    bind_addresses: ['::', '0.0.0.0']
 
     # How many days remaining on a certificate before it is renewed.
     #
-    #reprovision_threshold: 30
+    reprovision_threshold: 30
 
     # The domain that the certificate should be for. Normally this
     # should be the same as your Matrix domain (i.e., 'server_name'), but,
@@ -430,7 +430,7 @@ acme:
     #
     # If not set, defaults to your 'server_name'.
     #
-    #domain: matrix.example.com
+    domain: matrix.example.com
 
     # file to use for the account key. This will be generated if it doesn't
     # exist.

synapse/config/_base.py

@@ -181,6 +181,11 @@ def generate_config(
         generate_secrets=False,
         report_stats=None,
         open_private_ports=False,
+        listeners=None,
+        database_conf=None,
+        tls_certificate_path=None,
+        tls_private_key_path=None,
+        acme_domain=None,
     ):
         """Build a default configuration file
 
@@ -207,6 +212,33 @@ def generate_config(
             open_private_ports (bool): True to leave private ports (such as the non-TLS
                 HTTP listener) open to the internet.
 
+            listeners (list(dict)|None): A list of descriptions of the listeners
+                synapse should start with each of which specifies a port (str), a list of
+                resources (list(str)), tls (bool) and type (str). For example:
+                [{
+                    "port": 8448,
+                    "resources": [{"names": ["federation"]}],
+                    "tls": True,
+                    "type": "http",
+                },
+                {
+                    "port": 443,
+                    "resources": [{"names": ["client"]}],
+                    "tls": False,
+                    "type": "http",
+                }],
+
+
+            database (str|None): The database type to configure, either `psycog2`
+                or `sqlite3`.
+
+            tls_certificate_path (str|None): The path to the tls certificate.
+
+            tls_private_key_path (str|None): The path to the tls private key.
+
+            acme_domain (str|None): The domain acme will try to validate. If
+                specified acme will be enabled.
+
         Returns:
             str: the yaml config file
         """
@@ -220,6 +252,11 @@ def generate_config(
                 generate_secrets=generate_secrets,
                 report_stats=report_stats,
                 open_private_ports=open_private_ports,
+                listeners=listeners,
+                database_conf=database_conf,
+                tls_certificate_path=tls_certificate_path,
+                tls_private_key_path=tls_private_key_path,
+                acme_domain=acme_domain,
             )
         )
 

synapse/config/database.py

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import os
+from textwrap import indent
+
+import yaml
 
 from ._base import Config
 
@@ -38,20 +41,28 @@ def read_config(self, config, **kwargs):
 
         self.set_databasepath(config.get("database_path"))
 
-    def generate_config_section(self, data_dir_path, **kwargs):
-        database_path = os.path.join(data_dir_path, "homeserver.db")
-        return (
-            """\
-        ## Database ##
-
-        database:
-          # The database engine name
+    def generate_config_section(self, data_dir_path, database_conf, **kwargs):
+        if not database_conf:
+            database_path = os.path.join(data_dir_path, "homeserver.db")
+            database_conf = (
+                """# The database engine name
           name: "sqlite3"
           # Arguments to pass to the engine
           args:
             # Path to the database
             database: "%(database_path)s"
+            """
+                % locals()
+            )
+        else:
+            database_conf = indent(yaml.dump(database_conf), " " * 10).lstrip()
+
+        return (
+            """\
+        ## Database ##
 
+        database:
+          %(database_conf)s
         # Number of events to cache in memory.
         #
         #event_cache_size: 10K

synapse/config/server.py

@@ -17,8 +17,11 @@
 
 import logging
 import os.path
+import re
+from textwrap import indent
 
 import attr
+import yaml
 from netaddr import IPSet
 
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
@@ -352,7 +355,7 @@ def has_tls_listener(self):
         return any(l["tls"] for l in self.listeners)
 
     def generate_config_section(
-        self, server_name, data_dir_path, open_private_ports, **kwargs
+        self, server_name, data_dir_path, open_private_ports, listeners, **kwargs
     ):
         _, bind_port = parse_and_validate_server_name(server_name)
         if bind_port is not None:
@@ -366,11 +369,68 @@ def generate_config_section(
         # Bring DEFAULT_ROOM_VERSION into the local-scope for use in the
         # default config string
         default_room_version = DEFAULT_ROOM_VERSION
+        secure_listeners = []
+        unsecure_listeners = []
+        private_addresses = ["::1", "127.0.0.1"]
+        if listeners:
+            for listener in listeners:
+                if listener["tls"]:
+                    secure_listeners.append(listener)
+                else:
+                    # If we don't want open ports we need to bind the listeners
+                    # to some address other than 0.0.0.0. Here we chose to use
+                    # localhost.
+                    # If the addresses are already bound we won't overwrite them
+                    # however.
+                    if not open_private_ports:
+                        listener.setdefault("bind_addresses", private_addresses)
+
+                    unsecure_listeners.append(listener)
+
+            secure_http_bindings = indent(
+                yaml.dump(secure_listeners), " " * 10
+            ).lstrip()
+
+            unsecure_http_bindings = indent(
+                yaml.dump(unsecure_listeners), " " * 10
+            ).lstrip()
+
+        if not unsecure_listeners:
+            unsecure_http_bindings = (
+                """- port: %(unsecure_port)s
+            tls: false
+            type: http
+            x_forwarded: true"""
+                % locals()
+            )
+
+            if not open_private_ports:
+                unsecure_http_bindings += (
+                    "\n            bind_addresses: ['::1', '127.0.0.1']"
+                )
+
+            unsecure_http_bindings += """
+
+            resources:
+              - names: [client, federation]
+                compress: false"""
+
+            if listeners:
+                # comment out this block
+                unsecure_http_bindings = "#" + re.sub(
+                    "\n {10}",
+                    lambda match: match.group(0) + "#",
+                    unsecure_http_bindings,
+                )
 
-        unsecure_http_binding = "port: %i\n            tls: false" % (unsecure_port,)
-        if not open_private_ports:
-            unsecure_http_binding += (
-                "\n            bind_addresses: ['::1', '127.0.0.1']"
+        if not secure_listeners:
+            secure_http_bindings = (
+                """#- port: %(bind_port)s
+          #  type: http
+          #  tls: true
+          #  resources:
+          #    - names: [client, federation]"""
+                % locals()
             )
 
         return (
@@ -556,25 +616,15 @@ def generate_config_section(
           # will also need to give Synapse a TLS key and certificate: see the TLS section
           # below.)
           #
-          #- port: %(bind_port)s
-          #  type: http
-          #  tls: true
-          #  resources:
-          #    - names: [client, federation]
+          %(secure_http_bindings)s
 
           # Unsecure HTTP listener: for when matrix traffic passes through a reverse proxy
           # that unwraps TLS.
           #
           # If you plan to use a reverse proxy, please see
           # https://github.com/matrix-org/synapse/blob/master/docs/reverse_proxy.rst.
           #
-          - %(unsecure_http_binding)s
-            type: http
-            x_forwarded: true
-
-            resources:
-              - names: [client, federation]
-                compress: false
+          %(unsecure_http_bindings)s
 
             # example additional_resources:
             #

synapse/config/tls.py

@@ -239,12 +239,38 @@ def read_certificate_from_disk(self, require_cert_and_key):
                 self.tls_fingerprints.append({"sha256": sha256_fingerprint})
 
     def generate_config_section(
-        self, config_dir_path, server_name, data_dir_path, **kwargs
+        self,
+        config_dir_path,
+        server_name,
+        data_dir_path,
+        tls_certificate_path,
+        tls_private_key_path,
+        acme_domain,
+        **kwargs
     ):
+        """If the acme_domain is specified acme will be enabled.
+        If the TLS paths are not specified the default will be certs in the
+        config directory"""
+
         base_key_name = os.path.join(config_dir_path, server_name)
 
-        tls_certificate_path = base_key_name + ".tls.crt"
-        tls_private_key_path = base_key_name + ".tls.key"
+        if bool(tls_certificate_path) != bool(tls_private_key_path):
+            raise ConfigError(
+                "Please specify both a cert path and a key path or neither."
+            )
+
+        tls_enabled = (
+            "" if tls_certificate_path and tls_private_key_path or acme_domain else "#"
+        )
+
+        if not tls_certificate_path:
+            tls_certificate_path = base_key_name + ".tls.crt"
+        if not tls_private_key_path:
+            tls_private_key_path = base_key_name + ".tls.key"
+
+        acme_enabled = bool(acme_domain)
+        acme_domain = "matrix.example.com"
+
         default_acme_account_file = os.path.join(data_dir_path, "acme_account.key")
 
         # this is to avoid the max line length. Sorrynotsorry
@@ -269,11 +295,11 @@ def generate_config_section(
         # instance, if using certbot, use `fullchain.pem` as your certificate,
         # not `cert.pem`).
         #
-        #tls_certificate_path: "%(tls_certificate_path)s"
+        %(tls_enabled)stls_certificate_path: "%(tls_certificate_path)s"
 
         # PEM-encoded private key for TLS
         #
-        #tls_private_key_path: "%(tls_private_key_path)s"
+        %(tls_enabled)stls_private_key_path: "%(tls_private_key_path)s"
 
         # Whether to verify TLS server certificates for outbound federation requests.
         #
@@ -340,10 +366,10 @@ def generate_config_section(
         #    permission to listen on port 80.
         #
         acme:
-            # ACME support is disabled by default. Uncomment the following line
-            # (and tls_certificate_path and tls_private_key_path above) to enable it.
+            # ACME support is disabled by default. Set this to `true` and uncomment
+            # tls_certificate_path and tls_private_key_path above to enable it.
             #
-            #enabled: true
+            enabled: %(acme_enabled)s
 
             # Endpoint to use to request certificates. If you only want to test,
             # use Let's Encrypt's staging url:
@@ -354,17 +380,17 @@ def generate_config_section(
             # Port number to listen on for the HTTP-01 challenge. Change this if
             # you are forwarding connections through Apache/Nginx/etc.
             #
-            #port: 80
+            port: 80
 
             # Local addresses to listen on for incoming connections.
             # Again, you may want to change this if you are forwarding connections
             # through Apache/Nginx/etc.
             #
-            #bind_addresses: ['::', '0.0.0.0']
+            bind_addresses: ['::', '0.0.0.0']
 
             # How many days remaining on a certificate before it is renewed.
             #
-            #reprovision_threshold: 30
+            reprovision_threshold: 30
 
             # The domain that the certificate should be for. Normally this
             # should be the same as your Matrix domain (i.e., 'server_name'), but,
@@ -378,7 +404,7 @@ def generate_config_section(
             #
             # If not set, defaults to your 'server_name'.
             #
-            #domain: matrix.example.com
+            domain: %(acme_domain)s
 
             # file to use for the account key. This will be generated if it doesn't
             # exist.