This change ensures PostgREST starts listening on a server socket only after it loaded the schema cache and is ready to handle requests. It is no longer going to return 503 errors during startup until the schema cache is loaded.
This is useful when multiple instances run on the same machine, for
example behind a proxy. Unix sockets for web and admin servers can then
be put in the same folder for each instance.
Can be helpful when writing tests as well.
Replaces the `Maybe [Text]` with `[Text]`. The `Maybe` is unnecessary
because we handle `Just []` and `Nothing` the same way.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
Schema cache query timings are only needed immediately after a schema-cache reload to emit SchemaCacheQueriedObs. Storing them inside SchemaCache makes the cache carry transient observability data that is not part of the cached schema state and is never used by request handling.
This change makes querySchemaCache to return query timings in a tuple in parallel to SchemaCache and removes dbQueryTimings field.
Remove internal schema cache load and relationship load sleep settings plus
the delay wrappers they enabled. Drop IO tests that depended on the removed
settings.
Right now metrics observation handler does not track database connections but updates a single Gauge based on HasqlPoolObs events. This is problematic because Hasql pool reports various connection events in multiple phases. The connection state machine is not simple and to precisely report the number of connections in various states, it is necessary to track their lifecycles.
This change adds a ConnTrack data structure and logic to track database connections lifecycles. At the moment it supports "connected" and "inUse" connection counts precisely. The "pgrst_db_pool_available" metric is implemented on top of ConnTrack instead of a simple Gauge.
This commit removes auth middleware for it hides
side effects and obscures logic. The auth operations
are now done in its own stage in the request-response
cycle.
It also removes the logging middleware because now
we instead use observation module to log the response.
PostgREST failed when querying role settings where current
role name contained uppercase letters. This commit resolves
it by quoting the CURRENT_USER.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
retryingSchemaCacheLoad flushes the pool upon every retry before it starts reloading the schema. This is too early as schema reloading might take some time during which new connections might be acquired. The consequence is that:
* upon successful schema cache reload we might have some connections created with the old schema cache
* we close connections upon each retry and under load we will keep closing and re-opening connections until schema cache load succeeds
This change is to make sure we flush the pool only after successful schema cache querying but before loading (so that connections acquired during loading wait for it and do not interfere with timing the loading process).
To avoid repeated querying of `pg_timezone_names` every time schema
cache is reset, `Prefer: timezone` can be disabled by setting
`db-timezone-enabled = false`.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
Some helpers are provided for introspecting metrics already (used in JWT cache tests). This change provides facilities to additionally validate emited Observation events.
A new Spec module is also implemented, adding basic tests of schema cache reloading - their main goal is to excercise the new infrastructure.
- Create separate test suite for observability tests
- Create wrapper script `postgrest-test-observability`
- Add to CI and `postgrest-check`
- Move JWT cache tests under observability tests
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
