Spawning from getting `HMAC incorrect` errors that seem unexplainable
except for the `registration_shared_secret` being misconfigured. It's
also possible my HMAC calculation is incorrect but every time I
double-check the result with the [known-good Python
example](553e124f76/docs/admin_api/register_api.md)
(which matches [Synapse's
source](24e849e483/synapse/rest/admin/users.py (L618-L633))),
it's as expected.
With these logs, we can actually debug whether
`registration_shared_secret` is being configured correctly or not.
It also helps specifically when using `registration_shared_secret_path`
since the default Synapse behavior (of creating the file and secret if
it doesn't exist) can mask deployment race condition where we would
start up Synapse before the `registration_shared_secret_path` file was
put in place:
> **`registration_shared_secret_path`**
>
> [...]
>
> If this file does not exist, Synapse will create a new shared secret
on startup and store it in this file.
>
> *-- [Synapse config
docs](6521406a37/docs/usage/configuration/config_documentation.md (registration_shared_secret_path))*
This only applies to the [`POST
/_synapse/admin/v1/register`](553e124f76/docs/admin_api/register_api.md)
endpoint but does log very sensitive information so we've made it so you
have to explicitly enable the logs by configuring
`synapse.rest.admin.users.registration_debug` (does not inherit root log
level) (via our new `ExplicitlyConfiguredLogger`)
`homeserver.yaml`
```yaml
log_config: "/myserver.log.config.yaml"
```
`myserver.log.config.yaml`
```yaml
version: 1
formatters:
precise:
format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
handlers:
# ... file/buffer handler (see `sample_log_config.yaml`)
# A handler that writes logs to stderr. Unused by default, but can be used
# instead of "buffer" and "file" in the logger handlers.
console:
class: logging.StreamHandler
formatter: precise
loggers:
synapse.storage.SQL:
# beware: increasing this to DEBUG will make synapse log sensitive
# information such as access tokens.
level: INFO
# Has to be explicitly configured as such. Will not inherit from the root level even if it's set to DEBUG
synapse.rest.admin.users.registration_debug:
level: DEBUG
root:
level: INFO
handlers: [console]
disable_existing_loggers: false
```
