Eric Eastwood 9cc4001778
Better explain logcontext in run_in_background(...) and run_as_background_process(...) (#18900)
Also adds a section in the docs explaining the `sentinel` logcontext.

Spawning from https://github.com/element-hq/synapse/pull/18870


### Testing strategy

1. Run Synapse normally and with `daemonize: true`: `poetry run
synapse_homeserver --config-path homeserver.yaml`
 1. Execute some requests
 1. Shutdown the server
 1. Look for any bad log entries in your homeserver logs:
    - `Expected logging context sentinel but found main`
    - `Expected logging context main was lost`
    - `Expected previous context`
    - `utime went backwards!`/`stime went backwards!`
- `Called stop on logcontext POST-0 without recording a start rusage`
    - `Background process re-entered without a proc`

Twisted trial tests:

 1. Run full Twisted trial test suite.
1. Check the logs for `Test starting with non-sentinel logging context ...`
2025-09-10 10:22:53 -05:00
..
2024-02-06 09:26:55 +00:00
2025-08-11 16:43:45 +01:00
2023-12-13 16:37:10 +00:00
2023-12-13 16:15:22 +00:00
2023-12-13 16:37:10 +00:00
2025-05-20 13:31:05 +00:00
2023-12-13 16:15:22 +00:00
2023-12-13 16:15:22 +00:00
2023-12-13 16:37:10 +00:00
2025-08-04 15:48:45 +02:00

Synapse Documentation

The documentation is currently hosted here. Please update any links to point to the new website instead.

About

This directory currently holds a series of markdown files documenting how to install, use and develop Synapse. The documentation is readable directly from this repository, but it is recommended to instead browse through the website for easier discoverability.

Adding to the documentation

Most of the documentation currently exists as top-level files, as when organising them into a structured website, these files were kept in place so that existing links would not break. The rest of the documentation is stored in folders, such as setup, usage, and development etc. All new documentation files should be placed in structured folders. For example:

To create a new user-facing documentation page about a new Single Sign-On protocol named "MyCoolProtocol", one should create a new file with a relevant name, such as "my_cool_protocol.md". This file might fit into the documentation structure at:

  • Usage
    • Configuration
      • User Authentication
        • Single Sign-On
          • My Cool Protocol

Given that, one would place the new file under usage/configuration/user_authentication/single_sign_on/my_cool_protocol.md.

Note that the structure of the documentation (and thus the left sidebar on the website) is determined by the list in SUMMARY.md. The final thing to do when adding a new page is to add a new line linking to the new documentation file:

- [My Cool Protocol](usage/configuration/user_authentication/single_sign_on/my_cool_protocol.md)

Building the documentation

The documentation is built with mdbook, and the outline of the documentation is determined by the structure of SUMMARY.md.

First, get mdbook. Then, from the root of the repository, build the documentation with:

mdbook build

The rendered contents will be outputted to a new book/ directory at the root of the repository. Please note that index.html is not built by default, it is created by copying over the file welcome_and_overview.html to index.html during deployment. Thus, when running mdbook serve locally the book will initially show a 404 in place of the index due to the above. Do not be alarmed!

You can also have mdbook host the docs on a local webserver with hot-reload functionality via:

mdbook serve

The URL at which the docs can be viewed at will be logged.

Synapse configuration documentation

The Configuration Manual page is generated from a YAML file, schema/synapse-config.schema.yaml. To add new options or modify existing ones, first edit that file, then run scripts-dev/gen_config_documentation.py to generate an updated Configuration Manual markdown file.

Build the book as described above to preview it in a web browser.

Configuration and theming

The look and behaviour of the website is configured by the book.toml file at the root of the repository. See mdbook's documentation on configuration for available options.

The site can be themed and additionally extended with extra UI and features. See website_files/README.md for details.