forked from Fediversity/Fediversity
74 lines
2.3 KiB
Markdown
74 lines
2.3 KiB
Markdown
---
|
|
gitea: none
|
|
include_toc: true
|
|
---
|
|
|
|
# Reverse proxy for Synapse with workers
|
|
|
|
Changing nginx's configuration from a reverse proxy for a normal, monolithi
|
|
Synapse to one for a Synapse that uses workers, quite a lot has to be changed.
|
|
|
|
As mentioned in [Synapse with workers](../synapse/workers.md#synapse), we're
|
|
changing from network sockets to UNIX sockets.
|
|
|
|
Because we're going to have to forward a lot of specific requests to all kinds
|
|
of workers, we'll split the configuration into a few bits:
|
|
|
|
* all `proxy_forward` settings
|
|
* all `location` definitions
|
|
* maps that define variables
|
|
* upstreams that point to the correct socket(s) with the correct settings
|
|
* settings for private access
|
|
* connection optimizations
|
|
|
|
Some of these go into `/etc/nginx/conf.d` because they are part of the
|
|
configuration of nginx itself, others go into `/etc/nginx/snippets` because we
|
|
need to include them several times in different places.
|
|
|
|
|
|
# Maps
|
|
|
|
A map sets a variable based on, usually, another variable. One case we use is
|
|
determining the type of sync a client is doing. A normal sync, simply
|
|
updating an existing session, is a rather lightweight operation.
|
|
|
|
An initial sync, meaning a full sync because the session is brand new, is not
|
|
so lightweight.
|
|
|
|
A normal sync can be recognised by the `since` bit in the request: it tells
|
|
the server when its last sync was. If there is no `since`, we're dealing with
|
|
an initial sync.
|
|
|
|
Initial syncs are forwarded to the `initial_sync` workers, the normal syncs to
|
|
`normal_sync`.
|
|
|
|
We decide to which type of worker to forward the sync request to by looking at
|
|
the presence or absence of `since`: if it's there, it's a normal sync and we
|
|
set the variable `$sync` to `normal_sync`. If it's not there, we set `$sync` to
|
|
`initial_sync`.
|
|
|
|
The last bit is to foward the request to the upstream `$sync`. This is what
|
|
that map looks like:
|
|
|
|
```
|
|
map $arg_since $sync {
|
|
default normal_sync;
|
|
'' initial_sync;
|
|
}
|
|
```
|
|
|
|
We filter the argument `since` by using `$arg_since`, see [the index of
|
|
variables in nginx](https://nginx.org/en/docs/varindex.html) for more
|
|
variables we can use.
|
|
|
|
By default we set `$sync` to `normal_sync`, unless the argument `since` is
|
|
empty (absent); then we set `$sync` to `initial_sync`.
|
|
|
|
After that, we forward the request:
|
|
|
|
```
|
|
proxy_pass http://$sync;
|
|
```
|
|
|
|
|