* add types to represent unparsed http gql requests
This will help when we add caching of frequently used ASTs
* query plan caching
* move livequery to execute
* add multiplexed module
* session variable can be customised depending on the context
Previously the value was always "current_setting('hasura.user')"
* get rid of typemap requirement in reusable plan
* subscriptions are multiplexed when possible
* use lazytx for introspection to avoid acquiring a pg connection
* refactor to make execute a completely decoupled module
* don't issue a transaction for a query
* don't use current setting for explained sql
* move postgres related types to a different module
* validate variableValues on postgres before multiplexing subs
* don't user current_setting for queries over ws
* plan_cache is only visible when developer flag is enabled
* introduce 'batch size' when multiplexing subscriptions
* bump stackage to 13.16
* fix schema_stitching test case error code
* store hashes instead of actual responses for subscriptions
* internal api to dump subscriptions state
* remove PlanCache from SchemaCacheRef
* allow live query options to be configured on server startup
* capture metrics for multiplexed subscriptions
* more metrics captured for multiplexed subs
* switch to tvar based hashmap for faster snapshotting
* livequery modules do not expose internal details
* fix typo in live query env vars
* switch to hasura's pg-client-hs
1. Haskel library `pg-client-hs` has been updated to expose a function that helps listen to `postgres` notifications over a `channel` in this [PR](https://github.com/hasura/pg-client-hs/pull/5)
2. The server records an event in a table `hdb_catalog.hdb_cache_update_event` whenever any `/v1/query` (that changes metadata) is requested. A trigger notifies a `cache update` event via `hasura_cache_update` channel
3. The server runs two concurrent threads namely `listener` and `processor`. The `listener` thread listens to events on `hasura_cache_update` channel and pushed into a `Queue`. The `processor` thread fetches events from that `Queue` and processes it. Thus server rebuilds schema cache from database and updates.
If returning field contains nested selections then mutation is performed in two steps
1. Mutation is performed with returning columns of any primary key and unique constraints
2. returning fields are queried on rows returned by selecting from table by filtering with column values returned in Step 1.
Since mutation takes two courses based on selecting relations in returning field, it is hard to maintain sequence of prepared arguments (PrepArg) generated while resolving returning field. So, we're using txtConverter instead of prepare to resolve mutation fields.
* console now works on local builds of the server
1. local console assets can be served at /static/ by a build time flag
'local-console'. This can be set with stack as follows:
`stack build --flag graphql-engine:local-console`
2. the --root-dir option is removed which was used as a temporary hack
for serving graphiql
3. remove server's graphiql source code
* remove phase one/two distinction and hdbquery typeclass
* move extensions to default-extensions
* switch to LazyTx which only acquires a connection if needed
* move defns from TH module into Ops module
* remove tojson orphan instance for http exception
* remove orphan instance for dmlp1
* getTopLevelNodes will not throw any exceptions
When using self referential relationships in boolean expressions, the exists clause incorrectly uses the table names to qualify columns which will be the same for parent table and the child table. This is now fixed by generating unique aliases as we traverse down the relationships.
JWT config now takes an optional jwk_url parameter (which points to published JWK Set). This is useful for providers who rotate their JWK Set.
Optional jwk_url parameter is taken. The published JWK set under that URL should be in standard JWK format (tools.ietf.org/html/rfc7517#section-4.8).
If the response contains an Expires header, the JWK set is automatically refreshed.
The API:
1. HGE has `--jwt-secret` flag or `HASURA_GRAPHQL_JWT_SECRET` env var. The value of which is a JSON.
2. The structure of this JSON is: `{"type": "<standard-JWT-algorithms>", "key": "<the-key>"}`
`type` : Standard JWT algos : `HS256`, `RS256`, `RS512` etc. (see jwt.io).
`key`:
i. Incase of symmetric key, the key as it is.
ii. Incase of asymmetric keys, only the public key, in a PEM encoded string or as a X509 certificate.
3. The claims in the JWT token must contain the following:
i. `x-hasura-default-role` field: default role of that user
ii. `x-hasura-allowed-roles` : A list of allowed roles for the user. The default role is overriden by `x-hasura-role` header.
4. The claims in the JWT token, can have other `x-hasura-*` fields where their values can only be strings.
5. The JWT tokens are sent as `Authorization: Bearer <token>` headers.
---
To test:
1. Generate a shared secret (for HMAC-SHA256) or RSA key pair.
2. Goto https://jwt.io/ , add the keys
3. Edit the claims to have `x-hasura-role` (mandatory) and other `x-hasura-*` fields. Add permissions related to the claims to test permissions.
4. Start HGE with `--jwt-secret` flag or `HASURA_GRAPHQL_JWT_SECRET` env var, which takes a JSON string: `{"type": "HS256", "key": "mylongsharedsecret"}` or `{"type":"RS256", "key": "<PEM-encoded-public-key>"}`
5. Copy the JWT token from jwt.io and use it in the `Authorization: Bearer <token>` header.
---
TODO: Support EC public keys. It is blocked on frasertweedale/hs-jose#61
* filter schema identifiers to conform to graphql naming scheme,closes #134
Filter out tables, columns, relationships etc which does not conform to
graphql naming scheme.
This ensures GraphiQL initialisation works properly for existing
databases.
* rename `isGraphQLConform` to `isValidName`
* rename all graphQL validators
* server: basic test setup
* server: use the default transaction mode
* server: basic tests in yaml files
* server: restructure test setup and some more tests
