Merge remote-tracking branch 'origin/develop' into rav/drop_py35

CHANGES.md

-Synapse 1.31.0rc1 (2021-03-30)
-==============================
-**Note:** As announced in v1.25.0, and in line with the deprecation policy for platform dependencies, this is the last release to support Python 3.5 and PostgreSQL 9.5. Future versions of Synapse will require Python 3.6+ and PostgreSQL 9.6+.
+Synapse 1.31.0 (2021-04-06)
+===========================
+**Note:** As announced in v1.25.0, and in line with the deprecation policy for platform dependencies, this is the last release to support Python 3.5 and PostgreSQL 9.5. Future versions of Synapse will require Python 3.6+ and PostgreSQL 9.6+, as per our [deprecation policy](docs/deprecation_policy.md).
 This is also the last release that the Synapse team will be publishing packages for Debian Stretch and Ubuntu Xenial.
+
+Improved Documentation
+----------------------
+
+- Add a document describing the deprecation policy for platform dependencies. ([\#9723](https://github.com/matrix-org/synapse/issues/9723))
+
+
+Internal Changes
+----------------
+
+- Revert using `dmypy run` in lint script. ([\#9720](https://github.com/matrix-org/synapse/issues/9720))
+- Pin flake8-bugbear's version. ([\#9734](https://github.com/matrix-org/synapse/issues/9734))
+
+
+Synapse 1.31.0rc1 (2021-03-30)
+==============================
+
 Features
 --------

INSTALL.md

@@ -38,6 +38,7 @@ There are 3 steps to follow under **Installation Instructions**.
     - [URL previews](#url-previews)
     - [Troubleshooting Installation](#troubleshooting-installation)
 
+
 ## Choosing your server name
 
 It is important to choose the name for your server before you install Synapse,
@@ -542,7 +543,7 @@ Alternatively, you can do so from the command line. This can be done as follows:
     register_new_matrix_user -c homeserver.yaml http://localhost:8008
     ```
 
-This will prompt you to add details for the new user, and will then connect to 
+This will prompt you to add details for the new user, and will then connect to
 the running Synapse to create the new user. For example:
 ```
 New user localpart: erikj

README.rst

@@ -314,6 +314,15 @@ Testing with SyTest is recommended for verifying that changes related to the
 Client-Server API are functioning correctly. See the `installation instructions
 <https://github.com/matrix-org/sytest#installing>`_ for details.
 
+
+Platform dependencies
+=====================
+
+Synapse uses a number of platform dependencies such as Python and PostgreSQL,
+and aims to follow supported upstream versions. See the
+`<docs/deprecation_policy.md>`_ document for more details.
+
+
 Troubleshooting
 ===============
 
@@ -384,12 +393,17 @@ massive excess of outgoing federation requests (see `discussion
 indicate that your server is also issuing far more outgoing federation
 requests than can be accounted for by your users' activity, this is a
 likely cause. The misbehavior can be worked around by setting
-``use_presence: false`` in the Synapse config file.
+the following in the Synapse config file:
+
+.. code-block:: yaml
+
+   presence:
+       enabled: false
 
 People can't accept room invitations from me
 --------------------------------------------
 
-The typical failure mode here is that you send an invitation to someone 
+The typical failure mode here is that you send an invitation to someone
 to join a room or direct chat, but when they go to accept it, they get an
 error (typically along the lines of "Invalid signature"). They might see
 something like the following in their logs::

changelog.d/8926.bugfix

+Prevent `synapse_forward_extremities` and `synapse_excess_extremity_events` Prometheus metrics from initially reporting zero-values after startup.

changelog.d/9491.feature

+Add a Synapse module for routing presence updates between users.

changelog.d/9654.feature

+Include request information in structured logging output.

changelog.d/9720.misc

-Revert using `dmypy run` in lint script.

changelog.d/9725.bugfix

+Fix longstanding bug which caused `duplicate key value violates unique constraint "remote_media_cache_thumbnails_media_origin_media_id_thumbna_key"` errors.

changelog.d/9730.misc

+Add type hints to expiring cache.

changelog.d/9734.misc

-Pin flake8-bugbear's version.
\ No newline at end of file

changelog.d/9735.feature

+Add experimental support for [MSC3083](https://github.com/matrix-org/matrix-doc/pull/3083): restricting room access via group membership.

changelog.d/9736.misc

+Convert various testcases to `HomeserverTestCase`.

changelog.d/9743.misc

+Add missing type hints to federation handler and server.

changelog.d/9753.misc

+Check that a `ConfigError` is raised, rather than simply `Exception`, when appropriate in homeserver config file generation tests.
\ No newline at end of file

changelog.d/9765.docker

+Move opencontainers labels to the final Docker image such that users can inspect them.

changelog.d/9770.bugfix

+Fix bug where sharded federation senders could get stuck repeatedly querying the DB in a loop, using lots of CPU.

debian/changelog

+matrix-synapse-py3 (1.31.0) stable; urgency=medium
+
+  * New synapse release 1.31.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Tue, 06 Apr 2021 13:08:29 +0100
+
 matrix-synapse-py3 (1.30.1) stable; urgency=medium
 
   * New synapse release 1.30.1.

docker/Dockerfile

@@ -18,11 +18,6 @@ ARG PYTHON_VERSION=3.8
 ###
 FROM docker.io/python:${PYTHON_VERSION}-slim as builder
 
-LABEL org.opencontainers.image.url='https://matrix.org/docs/projects/server/synapse'
-LABEL org.opencontainers.image.documentation='https://github.com/matrix-org/synapse/blob/master/docker/README.md'
-LABEL org.opencontainers.image.source='https://github.com/matrix-org/synapse.git'
-LABEL org.opencontainers.image.licenses='Apache-2.0'
-
 # install the OS build deps
 RUN apt-get update && apt-get install -y \
     build-essential \
@@ -66,6 +61,11 @@ RUN pip install --prefix="/install" --no-deps --no-warn-script-location /synapse
 
 FROM docker.io/python:${PYTHON_VERSION}-slim
 
+LABEL org.opencontainers.image.url='https://matrix.org/docs/projects/server/synapse'
+LABEL org.opencontainers.image.documentation='https://github.com/matrix-org/synapse/blob/master/docker/README.md'
+LABEL org.opencontainers.image.source='https://github.com/matrix-org/synapse.git'
+LABEL org.opencontainers.image.licenses='Apache-2.0'
+
 RUN apt-get update && apt-get install -y \
     curl \
     gosu \

docs/deprecation_policy.md

+Deprecation Policy for Platform Dependencies
+============================================
+
+Synapse has a number of platform dependencies, including Python and PostgreSQL.
+This document outlines the policy towards which versions we support, and when we
+drop support for versions in the future.
+
+
+Policy
+------
+
+Synapse follows the upstream support life cycles for Python and PostgreSQL,
+i.e. when a version reaches End of Life Synapse will withdraw support for that
+version in future releases.
+
+Details on the upstream support life cycles for Python and PostgreSQL are
+documented at https://endoflife.date/python and
+https://endoflife.date/postgresql.
+
+
+Context
+-------
+
+It is important for system admins to have a clear understanding of the platform
+requirements of Synapse and its deprecation policies so that they can
+effectively plan upgrading their infrastructure ahead of time. This is
+especially important in contexts where upgrading the infrastructure requires
+auditing and approval from a security team, or where otherwise upgrading is a
+long process.
+
+By following the upstream support life cycles Synapse can ensure that its
+dependencies continue to get security patches, while not requiring system admins
+to constantly update their platform dependencies to the latest versions.

docs/presence_router_module.md

+# Presence Router Module
+
+Synapse supports configuring a module that can specify additional users
+(local or remote) to should receive certain presence updates from local
+users.
+
+Note that routing presence via Application Service transactions is not
+currently supported.
+
+The presence routing module is implemented as a Python class, which will
+be imported by the running Synapse.
+
+## Python Presence Router Class
+
+The Python class is instantiated with two objects:
+
+* A configuration object of some type (see below).
+* An instance of `synapse.module_api.ModuleApi`.
+
+It then implements methods related to presence routing.
+
+Note that one method of `ModuleApi` that may be useful is:
+
+```python
+async def ModuleApi.send_local_online_presence_to(users: Iterable[str]) -> None
+```
+
+which can be given a list of local or remote MXIDs to broadcast known, online user
+presence to (for those users that the receiving user is considered interested in). 
+It does not include state for users who are currently offline, and it can only be
+called on workers that support sending federation.
+
+### Module structure
+
+Below is a list of possible methods that can be implemented, and whether they are
+required.
+
+#### `parse_config`
+
+```python
+def parse_config(config_dict: dict) -> Any
+```
+
+**Required.** A static method that is passed a dictionary of config options, and
+  should return a validated config object. This method is described further in
+  [Configuration](#configuration).
+
+#### `get_users_for_states`
+
+```python
+async def get_users_for_states(
+    self,
+    state_updates: Iterable[UserPresenceState],
+) -> Dict[str, Set[UserPresenceState]]:
+```
+
+**Required.** An asynchronous method that is passed an iterable of user presence
+state. This method can determine whether a given presence update should be sent to certain
+users. It does this by returning a dictionary with keys representing local or remote
+Matrix User IDs, and values being a python set
+of `synapse.handlers.presence.UserPresenceState` instances.
+
+Synapse will then attempt to send the specified presence updates to each user when
+possible.
+
+#### `get_interested_users`
+
+```python
+async def get_interested_users(self, user_id: str) -> Union[Set[str], str]
+```
+
+**Required.** An asynchronous method that is passed a single Matrix User ID. This
+method is expected to return the users that the passed in user may be interested in the
+presence of. Returned users may be local or remote. The presence routed as a result of
+what this method returns is sent in addition to the updates already sent between users
+that share a room together. Presence updates are deduplicated.
+
+This method should return a python set of Matrix User IDs, or the object
+`synapse.events.presence_router.PresenceRouter.ALL_USERS` to indicate that the passed
+user should receive presence information for *all* known users.
+
+For clarity, if the user `@alice:example.org` is passed to this method, and the Set
+`{"@bob:example.com", "@charlie:somewhere.org"}` is returned, this signifies that Alice
+should receive presence updates sent by Bob and Charlie, regardless of whether these
+users share a room.
+
+### Example
+
+Below is an example implementation of a presence router class.
+
+```python
+from typing import Dict, Iterable, Set, Union
+from synapse.events.presence_router import PresenceRouter
+from synapse.handlers.presence import UserPresenceState
+from synapse.module_api import ModuleApi
+
+class PresenceRouterConfig:
+    def __init__(self):
+        # Config options with their defaults
+        # A list of users to always send all user presence updates to
+        self.always_send_to_users = []  # type: List[str]
+        
+        # A list of users to ignore presence updates for. Does not affect
+        # shared-room presence relationships
+        self.blacklisted_users = []  # type: List[str]
+
+class ExamplePresenceRouter:
+    """An example implementation of synapse.presence_router.PresenceRouter.
+    Supports routing all presence to a configured set of users, or a subset
+    of presence from certain users to members of certain rooms.
+
+    Args:
+        config: A configuration object.
+        module_api: An instance of Synapse's ModuleApi.
+    """
+    def __init__(self, config: PresenceRouterConfig, module_api: ModuleApi):
+        self._config = config
+        self._module_api = module_api
+
+    @staticmethod
+    def parse_config(config_dict: dict) -> PresenceRouterConfig:
+        """Parse a configuration dictionary from the homeserver config, do
+        some validation and return a typed PresenceRouterConfig.
+
+        Args:
+            config_dict: The configuration dictionary.
+
+        Returns:
+            A validated config object.
+        """
+        # Initialise a typed config object
+        config = PresenceRouterConfig()
+        always_send_to_users = config_dict.get("always_send_to_users")
+        blacklisted_users = config_dict.get("blacklisted_users")
+
+        # Do some validation of config options... otherwise raise a
+        # synapse.config.ConfigError.
+        config.always_send_to_users = always_send_to_users
+        config.blacklisted_users = blacklisted_users
+
+        return config
+
+    async def get_users_for_states(
+        self,
+        state_updates: Iterable[UserPresenceState],
+    ) -> Dict[str, Set[UserPresenceState]]:
+        """Given an iterable of user presence updates, determine where each one
+        needs to go. Returned results will not affect presence updates that are
+        sent between users who share a room.
+
+        Args:
+            state_updates: An iterable of user presence state updates.
+
+        Returns:
+          A dictionary of user_id -> set of UserPresenceState that the user should 
+          receive.
+        """
+        destination_users = {}  # type: Dict[str, Set[UserPresenceState]
+
+        # Ignore any updates for blacklisted users
+        desired_updates = set()
+        for update in state_updates:
+            if update.state_key not in self._config.blacklisted_users:
+                desired_updates.add(update)
+
+        # Send all presence updates to specific users
+        for user_id in self._config.always_send_to_users:
+            destination_users[user_id] = desired_updates
+
+        return destination_users
+
+    async def get_interested_users(
+        self,
+        user_id: str,
+    ) -> Union[Set[str], PresenceRouter.ALL_USERS]:
+        """
+        Retrieve a list of users that `user_id` is interested in receiving the
+        presence of. This will be in addition to those they share a room with.
+        Optionally, the object PresenceRouter.ALL_USERS can be returned to indicate
+        that this user should receive all incoming local and remote presence updates.
+
+        Note that this method will only be called for local users.
+
+        Args:
+          user_id: A user requesting presence updates.
+
+        Returns:
+          A set of user IDs to return additional presence updates for, or
+          PresenceRouter.ALL_USERS to return presence updates for all other users.
+        """
+        if user_id in self._config.always_send_to_users:
+            return PresenceRouter.ALL_USERS
+
+        return set()
+```
+
+#### A note on `get_users_for_states` and `get_interested_users`
+
+Both of these methods are effectively two different sides of the same coin. The logic
+regarding which users should receive updates for other users should be the same 
+between them.
+
+`get_users_for_states` is called when presence updates come in from either federation 
+or local users, and is used to either direct local presence to remote users, or to
+wake up the sync streams of local users to collect remote presence.
+
+In contrast, `get_interested_users` is used to determine the users that presence should
+be fetched for when a local user is syncing. This presence is then retrieved, before
+being fed through `get_users_for_states` once again, with only the syncing user's
+routing information pulled from the resulting dictionary.
+
+Their routing logic should thus line up, else you may run into unintended behaviour.
+
+## Configuration
+
+Once you've crafted your module and installed it into the same Python environment as
+Synapse, amend your homeserver config file with the following.
+
+```yaml
+presence:
+  routing_module:
+    module: my_module.ExamplePresenceRouter
+    config:
+      # Any configuration options for your module. The below is an example.
+      # of setting options for ExamplePresenceRouter.
+      always_send_to_users: ["@presence_gobbler:example.org"]
+      blacklisted_users:
+        - "@alice:example.com"
+        - "@bob:example.com"
+      ...
+```
+
+The contents of `config` will be passed as a Python dictionary to the static
+`parse_config` method of your class. The object returned by this method will
+then be passed to the `__init__` method of your module as `config`.