fixes #9171

There's some prelimiary work here to pull out the construction of a jinja environment to a separate function.

I wanted to load the template at display time rather than load time, so that it's easy to update on the fly. Honestly, I think we should do this with all our templates: the risk of ending up with malformed templates is far outweighed by the improved turnaround time for an admin trying to update them.

Fixes #8966.

* Factor out build_synapse_client_resource_tree

Start a function which will mount resources common to all workers.

* Move sso init into build_synapse_client_resource_tree

... so that we don't have to do it for each worker

* Fix SSO-login-via-a-worker

Expose the SSO login endpoints on workers, like the documentation says.

* Update workers config for new endpoints

Add documentation for endpoints recently added (#8942, #9017, #9262)

* remove submit_token from workers endpoints list

this *doesn't* work on workers (yet).

* changelog

* Add a comment about the odd path for SAML2Resource

There are going to be a couple of paths to get to the final step of SSO reg, and I want the URL in the browser to consistent. So, let's move the final step onto a separate path, which we redirect to.

We've decided to add a 'brand' field to help clients decide how to style the
buttons.

Also, fix up the allowed characters for idp_id, while I'm in the area.

Synapse 1.26.0 (2021-01-27)
===========================

This release brings a new schema version for Synapse and rolling back to a previous
version is not trivial. Please review [UPGRADE.rst](UPGRADE.rst) for more details
on these changes and for general upgrade guidance.

No significant changes since 1.26.0rc2.

Synapse 1.26.0rc2 (2021-01-25)
==============================

Bugfixes
--------

- Fix receipts and account data not being sent down sync. Introduced in v1.26.0rc1. ([\#9193](https://github.com/matrix-org/synapse/issues/9193), [\#9195](https://github.com/matrix-org/synapse/issues/9195))
- Fix chain cover update to handle events with duplicate auth events. Introduced in v1.26.0rc1. ([\#9210](https://github.com/matrix-org/synapse/issues/9210))

Internal Changes
----------------

- Add an `oidc-` prefix to any `idp_id`s which are given in the `oidc_providers` configuration. ([\#9189](https://github.com/matrix-org/synapse/issues/9189))
- Bump minimum `psycopg2` version to v2.8. ([\#9204](https://github.com/matrix-org/synapse/issues/9204))

Synapse 1.26.0rc1 (2021-01-20)
==============================

This release brings a new schema version for Synapse and rolling back to a previous
version is not trivial. Please review [UPGRADE.rst](UPGRADE.rst) for more details
on these changes and for general upgrade guidance.

Features
--------

- Add support for multiple SSO Identity Providers. ([\#9015](https://github.com/matrix-org/synapse/issues/9015), [\#9017](https://github.com/matrix-org/synapse/issues/9017), [\#9036](https://github.com/matrix-org/synapse/issues/9036), [\#9067](https://github.com/matrix-org/synapse/issues/9067), [\#9081](https://github.com/matrix-org/synapse/issues/9081), [\#9082](https://github.com/matrix-org/synapse/issues/9082), [\#9105](https://github.com/matrix-org/synapse/issues/9105), [\#9107](https://github.com/matrix-org/synapse/issues/9107), [\#9109](https://github.com/matrix-org/synapse/issues/9109), [\#9110](https://github.com/matrix-org/synapse/issues/9110), [\#9127](https://github.com/matrix-org/synapse/issues/9127), [\#9153](https://github.com/matrix-org/synapse/issues/9153), [\#9154](https://github.com/matrix-org/synapse/issues/9154), [\#9177](https://github.com/matrix-org/synapse/issues/9177))
- During user-interactive authentication via single-sign-on, give a better error if the user uses the wrong account on the SSO IdP. ([\#9091](https://github.com/matrix-org/synapse/issues/9091))
- Give the `public_baseurl` a default value, if it is not explicitly set in the configuration file. ([\#9159](https://github.com/matrix-org/synapse/issues/9159))
- Improve performance when calculating ignored users in large rooms. ([\#9024](https://github.com/matrix-org/synapse/issues/9024))
- Implement [MSC2176](https://github.com/matrix-org/matrix-doc/pull/2176) in an experimental room version. ([\#8984](https://github.com/matrix-org/synapse/issues/8984))
- Add an admin API for protecting local media from quarantine. ([\#9086](https://github.com/matrix-org/synapse/issues/9086))
- Remove a user's avatar URL and display name when deactivated with the Admin API. ([\#8932](https://github.com/matrix-org/synapse/issues/8932))
- Update `/_synapse/admin/v1/users/<user_id>/joined_rooms` to work for both local and remote users. ([\#8948](https://github.com/matrix-org/synapse/issues/8948))
- Add experimental support for handling to-device messages on worker processes. ([\#9042](https://github.com/matrix-org/synapse/issues/9042), [\#9043](https://github.com/matrix-org/synapse/issues/9043), [\#9044](https://github.com/matrix-org/synapse/issues/9044), [\#9130](https://github.com/matrix-org/synapse/issues/9130))
- Add experimental support for handling `/keys/claim` and `/room_keys` APIs on worker processes. ([\#9068](https://github.com/matrix-org/synapse/issues/9068))
- Add experimental support for handling `/devices` API on worker processes. ([\#9092](https://github.com/matrix-org/synapse/issues/9092))
- Add experimental support for moving off receipts and account data persistence off master. ([\#9104](https://github.com/matrix-org/synapse/issues/9104), [\#9166](https://github.com/matrix-org/synapse/issues/9166))

Bugfixes
--------

- Fix a long-standing issue where an internal server error would occur when requesting a profile over federation that did not include a display name / avatar URL. ([\#9023](https://github.com/matrix-org/synapse/issues/9023))
- Fix a long-standing bug where some caches could grow larger than configured. ([\#9028](https://github.com/matrix-org/synapse/issues/9028))
- Fix error handling during insertion of client IPs into the database. ([\#9051](https://github.com/matrix-org/synapse/issues/9051))
- Fix bug where we didn't correctly record CPU time spent in `on_new_event` block. ([\#9053](https://github.com/matrix-org/synapse/issues/9053))
- Fix a minor bug which could cause confusing error messages from invalid configurations. ([\#9054](https://github.com/matrix-org/synapse/issues/9054))
- Fix incorrect exit code when there is an error at startup. ([\#9059](https://github.com/matrix-org/synapse/issues/9059))
- Fix `JSONDecodeError` spamming the logs when sending transactions to remote servers. ([\#9070](https://github.com/matrix-org/synapse/issues/9070))
- Fix "Failed to send request" errors when a client provides an invalid room alias. ([\#9071](https://github.com/matrix-org/synapse/issues/9071))
- Fix bugs in federation catchup logic that caused outbound federation to be delayed for large servers after start up. Introduced in v1.8.0 and v1.21.0. ([\#9114](https://github.com/matrix-org/synapse/issues/9114), [\#9116](https://github.com/matrix-org/synapse/issues/9116))
- Fix corruption of `pushers` data when a postgres bouncer is used. ([\#9117](https://github.com/matrix-org/synapse/issues/9117))
- Fix minor bugs in handling the `clientRedirectUrl` parameter for SSO login. ([\#9128](https://github.com/matrix-org/synapse/issues/9128))
- Fix "Unhandled error in Deferred: BodyExceededMaxSize" errors when .well-known files that are too large. ([\#9108](https://github.com/matrix-org/synapse/issues/9108))
- Fix "UnboundLocalError: local variable 'length' referenced before assignment" errors when the response body exceeds the expected size. This bug was introduced in v1.25.0. ([\#9145](https://github.com/matrix-org/synapse/issues/9145))
- Fix a long-standing bug "ValueError: invalid literal for int() with base 10" when `/publicRooms` is requested with an invalid `server` parameter. ([\#9161](https://github.com/matrix-org/synapse/issues/9161))

Improved Documentation
----------------------

- Add some extra docs for getting Synapse running on macOS. ([\#8997](https://github.com/matrix-org/synapse/issues/8997))
- Correct a typo in the `systemd-with-workers` documentation. ([\#9035](https://github.com/matrix-org/synapse/issues/9035))
- Correct a typo in `INSTALL.md`. ([\#9040](https://github.com/matrix-org/synapse/issues/9040))
- Add missing `user_mapping_provider` configuration to the Keycloak OIDC example. Contributed by @chris-ruecker. ([\#9057](https://github.com/matrix-org/synapse/issues/9057))
- Quote `pip install` packages when extras are used to avoid shells interpreting bracket characters. ([\#9151](https://github.com/matrix-org/synapse/issues/9151))

Deprecations and Removals
-------------------------

- Remove broken and unmaintained `demo/webserver.py` script. ([\#9039](https://github.com/matrix-org/synapse/issues/9039))

Internal Changes
----------------

- Improve efficiency of large state resolutions. ([\#8868](https://github.com/matrix-org/synapse/issues/8868), [\#9029](https://github.com/matrix-org/synapse/issues/9029), [\#9115](https://github.com/matrix-org/synapse/issues/9115), [\#9118](https://github.com/matrix-org/synapse/issues/9118), [\#9124](https://github.com/matrix-org/synapse/issues/9124))
- Various clean-ups to the structured logging and logging context code. ([\#8939](https://github.com/matrix-org/synapse/issues/8939))
- Ensure rejected events get added to some metadata tables. ([\#9016](https://github.com/matrix-org/synapse/issues/9016))
- Ignore date-rotated homeserver logs saved to disk. ([\#9018](https://github.com/matrix-org/synapse/issues/9018))
- Remove an unused column from `access_tokens` table. ([\#9025](https://github.com/matrix-org/synapse/issues/9025))
- Add a `-noextras` factor to `tox.ini`, to support running the tests with no optional dependencies. ([\#9030](https://github.com/matrix-org/synapse/issues/9030))
- Fix running unit tests when optional dependencies are not installed. ([\#9031](https://github.com/matrix-org/synapse/issues/9031))
- Allow bumping schema version when using split out state database. ([\#9033](https://github.com/matrix-org/synapse/issues/9033))
- Configure the linters to run on a consistent set of files. ([\#9038](https://github.com/matrix-org/synapse/issues/9038))
- Various cleanups to device inbox store. ([\#9041](https://github.com/matrix-org/synapse/issues/9041))
- Drop unused database tables. ([\#9055](https://github.com/matrix-org/synapse/issues/9055))
- Remove unused `SynapseService` class. ([\#9058](https://github.com/matrix-org/synapse/issues/9058))
- Remove unnecessary declarations in the tests for the admin API. ([\#9063](https://github.com/matrix-org/synapse/issues/9063))
- Remove `SynapseRequest.get_user_agent`. ([\#9069](https://github.com/matrix-org/synapse/issues/9069))
- Remove redundant `Homeserver.get_ip_from_request` method. ([\#9080](https://github.com/matrix-org/synapse/issues/9080))
- Add type hints to media repository. ([\#9093](https://github.com/matrix-org/synapse/issues/9093))
- Fix the wrong arguments being passed to `BlacklistingAgentWrapper` from `MatrixFederationAgent`. Contributed by Timothy Leung. ([\#9098](https://github.com/matrix-org/synapse/issues/9098))
- Reduce the scope of caught exceptions in `BlacklistingAgentWrapper`. ([\#9106](https://github.com/matrix-org/synapse/issues/9106))
- Improve `UsernamePickerTestCase`. ([\#9112](https://github.com/matrix-org/synapse/issues/9112))
- Remove dependency on `distutils`. ([\#9125](https://github.com/matrix-org/synapse/issues/9125))
- Enforce that replication HTTP clients are called with keyword arguments only. ([\#9144](https://github.com/matrix-org/synapse/issues/9144))
- Fix the Python 3.5 / old dependencies build in CI. ([\#9146](https://github.com/matrix-org/synapse/issues/9146))
- Replace the old `perspectives` option in the Synapse docker config file template with `trusted_key_servers`. ([\#9157](https://github.com/matrix-org/synapse/issues/9157))

Fixes #8928.

Co-authored-by: Dan Callahan <danc@element.io>

pip 21.0 stopped supporting Python 3.5.

Synapse 1.26.0rc2 (2021-01-25)
==============================

Bugfixes
--------

- Fix receipts and account data not being sent down sync. Introduced in v1.26.0rc1. ([\#9193](https://github.com/matrix-org/synapse/issues/9193), [\#9195](https://github.com/matrix-org/synapse/issues/9195))
- Fix chain cover update to handle events with duplicate auth events. Introduced in v1.26.0rc1. ([\#9210](https://github.com/matrix-org/synapse/issues/9210))

Internal Changes
----------------

- Add an `oidc-` prefix to any `idp_id`s which are given in the `oidc_providers` configuration. ([\#9189](https://github.com/matrix-org/synapse/issues/9189))
- Bump minimum `psycopg2` version to v2.8. ([\#9204](https://github.com/matrix-org/synapse/issues/9204))

As we use `execute_values` with the `fetch` parameter.

Introduced in #9104 

This wasn't picked up by the tests as this is all fine the first time you run Synapse (after upgrading), but then when you restart the wrong value is pulled from `stream_positions`. 

... to avoid clashes with other SSO mechanisms

`execute_batch` does fewer round trips in postgres than `executemany`, but does not give a correct `txn.rowcount` result after.

This avoids a warning when uploading packages to PyPI via twine.

Synapse 1.26.0rc1 (2021-01-20)
==============================

This release brings a new schema version for Synapse and rolling back to a previous
verious is not trivial.  Please review [UPGRADE.rst](UPGRADE.rst) for more details
on these changes  and for general upgrade guidance.

Features
--------

- Add support for multiple SSO Identity Providers. ([\#9015](https://github.com/matrix-org/synapse/issues/9015), [\#9017](https://github.com/matrix-org/synapse/issues/9017), [\#9036](https://github.com/matrix-org/synapse/issues/9036), [\#9067](https://github.com/matrix-org/synapse/issues/9067), [\#9081](https://github.com/matrix-org/synapse/issues/9081), [\#9082](https://github.com/matrix-org/synapse/issues/9082), [\#9105](https://github.com/matrix-org/synapse/issues/9105), [\#9107](https://github.com/matrix-org/synapse/issues/9107), [\#9109](https://github.com/matrix-org/synapse/issues/9109), [\#9110](https://github.com/matrix-org/synapse/issues/9110), [\#9127](https://github.com/matrix-org/synapse/issues/9127), [\#9153](https://github.com/matrix-org/synapse/issues/9153), [\#9154](https://github.com/matrix-org/synapse/issues/9154), [\#9177](https://github.com/matrix-org/synapse/issues/9177))
- During user-interactive authentication via single-sign-on, give a better error if the user uses the wrong account on the SSO IdP. ([\#9091](https://github.com/matrix-org/synapse/issues/9091))
- Give the `public_baseurl` a default value, if it is not explicitly set in the configuration file. ([\#9159](https://github.com/matrix-org/synapse/issues/9159))
- Improve performance when calculating ignored users in large rooms. ([\#9024](https://github.com/matrix-org/synapse/issues/9024))
- Implement [MSC2176](https://github.com/matrix-org/matrix-doc/pull/2176) in an experimental room version. ([\#8984](https://github.com/matrix-org/synapse/issues/8984))
- Add an admin API for protecting local media from quarantine. ([\#9086](https://github.com/matrix-org/synapse/issues/9086))
- Remove a user's avatar URL and display name when deactivated with the Admin API. ([\#8932](https://github.com/matrix-org/synapse/issues/8932))
- Update `/_synapse/admin/v1/users/<user_id>/joined_rooms` to work for both local and remote users. ([\#8948](https://github.com/matrix-org/synapse/issues/8948))
- Add experimental support for handling to-device messages on worker processes. ([\#9042](https://github.com/matrix-org/synapse/issues/9042), [\#9043](https://github.com/matrix-org/synapse/issues/9043), [\#9044](https://github.com/matrix-org/synapse/issues/9044), [\#9130](https://github.com/matrix-org/synapse/issues/9130))
- Add experimental support for handling `/keys/claim` and `/room_keys` APIs on worker processes. ([\#9068](https://github.com/matrix-org/synapse/issues/9068))
- Add experimental support for handling `/devices` API on worker processes. ([\#9092](https://github.com/matrix-org/synapse/issues/9092))
- Add experimental support for moving off receipts and account data persistence off master. ([\#9104](https://github.com/matrix-org/synapse/issues/9104), [\#9166](https://github.com/matrix-org/synapse/issues/9166))

Bugfixes
--------

- Fix a long-standing issue where an internal server error would occur when requesting a profile over federation that did not include a display name / avatar URL. ([\#9023](https://github.com/matrix-org/synapse/issues/9023))
- Fix a long-standing bug where some caches could grow larger than configured. ([\#9028](https://github.com/matrix-org/synapse/issues/9028))
- Fix error handling during insertion of client IPs into the database. ([\#9051](https://github.com/matrix-org/synapse/issues/9051))
- Fix bug where we didn't correctly record CPU time spent in `on_new_event` block. ([\#9053](https://github.com/matrix-org/synapse/issues/9053))
- Fix a minor bug which could cause confusing error messages from invalid configurations. ([\#9054](https://github.com/matrix-org/synapse/issues/9054))
- Fix incorrect exit code when there is an error at startup. ([\#9059](https://github.com/matrix-org/synapse/issues/9059))
- Fix `JSONDecodeError` spamming the logs when sending transactions to remote servers. ([\#9070](https://github.com/matrix-org/synapse/issues/9070))
- Fix "Failed to send request" errors when a client provides an invalid room alias. ([\#9071](https://github.com/matrix-org/synapse/issues/9071))
- Fix bugs in federation catchup logic that caused outbound federation to be delayed for large servers after start up. Introduced in v1.8.0 and v1.21.0. ([\#9114](https://github.com/matrix-org/synapse/issues/9114), [\#9116](https://github.com/matrix-org/synapse/issues/9116))
- Fix corruption of `pushers` data when a postgres bouncer is used. ([\#9117](https://github.com/matrix-org/synapse/issues/9117))
- Fix minor bugs in handling the `clientRedirectUrl` parameter for SSO login. ([\#9128](https://github.com/matrix-org/synapse/issues/9128))
- Fix "Unhandled error in Deferred: BodyExceededMaxSize" errors when .well-known files that are too large. ([\#9108](https://github.com/matrix-org/synapse/issues/9108))
- Fix "UnboundLocalError: local variable 'length' referenced before assignment" errors when the response body exceeds the expected size. This bug was introduced in v1.25.0. ([\#9145](https://github.com/matrix-org/synapse/issues/9145))
- Fix a long-standing bug "ValueError: invalid literal for int() with base 10" when `/publicRooms` is requested with an invalid `server` parameter. ([\#9161](https://github.com/matrix-org/synapse/issues/9161))

Improved Documentation
----------------------

- Add some extra docs for getting Synapse running on macOS. ([\#8997](https://github.com/matrix-org/synapse/issues/8997))
- Correct a typo in the `systemd-with-workers` documentation. ([\#9035](https://github.com/matrix-org/synapse/issues/9035))
- Correct a typo in `INSTALL.md`. ([\#9040](https://github.com/matrix-org/synapse/issues/9040))
- Add missing `user_mapping_provider` configuration to the Keycloak OIDC example. Contributed by @chris-ruecker. ([\#9057](https://github.com/matrix-org/synapse/issues/9057))
- Quote `pip install` packages when extras are used to avoid shells interpreting bracket characters. ([\#9151](https://github.com/matrix-org/synapse/issues/9151))

Deprecations and Removals
-------------------------

- Remove broken and unmaintained `demo/webserver.py` script. ([\#9039](https://github.com/matrix-org/synapse/issues/9039))

Internal Changes
----------------

- Improve efficiency of large state resolutions. ([\#8868](https://github.com/matrix-org/synapse/issues/8868), [\#9029](https://github.com/matrix-org/synapse/issues/9029), [\#9115](https://github.com/matrix-org/synapse/issues/9115), [\#9118](https://github.com/matrix-org/synapse/issues/9118), [\#9124](https://github.com/matrix-org/synapse/issues/9124))
- Various clean-ups to the structured logging and logging context code. ([\#8939](https://github.com/matrix-org/synapse/issues/8939))
- Ensure rejected events get added to some metadata tables. ([\#9016](https://github.com/matrix-org/synapse/issues/9016))
- Ignore date-rotated homeserver logs saved to disk. ([\#9018](https://github.com/matrix-org/synapse/issues/9018))
- Remove an unused column from `access_tokens` table. ([\#9025](https://github.com/matrix-org/synapse/issues/9025))
- Add a `-noextras` factor to `tox.ini`, to support running the tests with no optional dependencies. ([\#9030](https://github.com/matrix-org/synapse/issues/9030))
- Fix running unit tests when optional dependencies are not installed. ([\#9031](https://github.com/matrix-org/synapse/issues/9031))
- Allow bumping schema version when using split out state database. ([\#9033](https://github.com/matrix-org/synapse/issues/9033))
- Configure the linters to run on a consistent set of files. ([\#9038](https://github.com/matrix-org/synapse/issues/9038))
- Various cleanups to device inbox store. ([\#9041](https://github.com/matrix-org/synapse/issues/9041))
- Drop unused database tables. ([\#9055](https://github.com/matrix-org/synapse/issues/9055))
- Remove unused `SynapseService` class. ([\#9058](https://github.com/matrix-org/synapse/issues/9058))
- Remove unnecessary declarations in the tests for the admin API. ([\#9063](https://github.com/matrix-org/synapse/issues/9063))
- Remove `SynapseRequest.get_user_agent`. ([\#9069](https://github.com/matrix-org/synapse/issues/9069))
- Remove redundant `Homeserver.get_ip_from_request` method. ([\#9080](https://github.com/matrix-org/synapse/issues/9080))
- Add type hints to media repository. ([\#9093](https://github.com/matrix-org/synapse/issues/9093))
- Fix the wrong arguments being passed to `BlacklistingAgentWrapper` from `MatrixFederationAgent`. Contributed by Timothy Leung. ([\#9098](https://github.com/matrix-org/synapse/issues/9098))
- Reduce the scope of caught exceptions in `BlacklistingAgentWrapper`. ([\#9106](https://github.com/matrix-org/synapse/issues/9106))
- Improve `UsernamePickerTestCase`. ([\#9112](https://github.com/matrix-org/synapse/issues/9112))
- Remove dependency on `distutils`. ([\#9125](https://github.com/matrix-org/synapse/issues/9125))
- Enforce that replication HTTP clients are called with keyword arguments only. ([\#9144](https://github.com/matrix-org/synapse/issues/9144))
- Fix the Python 3.5 / old dependencies build in CI. ([\#9146](https://github.com/matrix-org/synapse/issues/9146))
- Replace the old `perspectives` option in the Synapse docker config file template with `trusted_key_servers`. ([\#9157](https://github.com/matrix-org/synapse/issues/9157))