The companion role was tightly coupled to Synapse through shared tags, worker routing, and lifecycle ordering. Keeping them separate added coordination overhead without practical benefits, especially for parallelized execution.
This merges the role into matrix-synapse while keeping companion logic organized under dedicated reverse_proxy_companion task/template subdirectories.
Compatibility is preserved:
- matrix_synapse_reverse_proxy_companion_* variable names remain unchanged
- install/setup companion-specific tags remain available
Cross-role/global wiring is now in group_vars (matrix-synapse section), while role defaults provide sensible standalone defaults and self-wiring for Synapse-owned values.
This adds a new routing mechanism for sync workers that resolves access tokens
to usernames via Synapse's whoami endpoint, enabling true user-level sticky
routing regardless of which device or token is used.
Previously, sticky routing relied on parsing the username from native Synapse
tokens (`syt_<base64 username>_...`), which only works with native Synapse auth
and provides device-level stickiness at best. This new approach works with any
auth system (native Synapse, MAS, etc.) because Synapse handles token validation
internally.
Implementation uses nginx's auth_request module with an njs script because:
- The whoami lookup requires an async HTTP subrequest (ngx.fetch)
- js_set handlers must return synchronously and don't support async operations
- auth_request allows the async lookup to complete, then captures the result
via response headers into nginx variables
The njs script:
- Extracts access tokens from Authorization header or query parameter
- Calls Synapse's whoami endpoint to resolve token -> username
- Caches results in a shared memory zone to minimize latency
- Returns the username via a `X-User-Identifier` header
The username is then used by nginx's upstream hash directive for consistent
worker selection. This leverages nginx's built-in health checking and failover.
Switching from doing "post-start" loop hacks to running the container
in 3 steps: `create` + potentially connect to additional networks + `start`.
This way, the container would be connected to all its networks even at
the very beginning of its life.
Slavi Pantaleev
Michael Hollister