graphql-engine/server/tests-py/queries/graphql_query
Karthikeyan Chinnakonda 92026b769f [Preview] Inherited roles for postgres read queries
fixes #3868

docker image - `hasura/graphql-engine:inherited-roles-preview-48b73a2de`

Note:

To be able to use the inherited roles feature, the graphql-engine should be started with the env variable `HASURA_GRAPHQL_EXPERIMENTAL_FEATURES` set to `inherited_roles`.

Introduction
------------

This PR implements the idea of multiple roles as presented in this [paper](https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/FGALanguageICDE07.pdf). The multiple roles feature in this PR can be used via inherited roles. An inherited role is a role which can be created by combining multiple singular roles. For example, if there are two roles `author` and `editor` configured in the graphql-engine, then we can create a inherited role with the name of `combined_author_editor` role which will combine the select permissions of the `author` and `editor` roles and then make GraphQL queries using the `combined_author_editor`.

How are select permissions of different roles are combined?
------------------------------------------------------------

A select permission includes 5 things:

1. Columns accessible to the role
2. Row selection filter
3. Limit
4. Allow aggregation
5. Scalar computed fields accessible to the role

 Suppose there are two roles, `role1` gives access to the `address` column with row filter `P1` and `role2` gives access to both the `address` and the `phone` column with row filter `P2` and we create a new role `combined_roles` which combines `role1` and `role2`.

Let's say the following GraphQL query is queried with the `combined_roles` role.

```graphql
query {
   employees {
     address
     phone
   }
}
```

This will translate to the following SQL query:

```sql

 select
    (case when (P1 or P2) then address else null end) as address,
    (case when P2 then phone else null end) as phone
 from employee
 where (P1 or P2)
```

The other parameters of the select permission will be combined in the following manner:

1. Limit - Minimum of the limits will be the limit of the inherited role
2. Allow aggregations - If any of the role allows aggregation, then the inherited role will allow aggregation
3. Scalar computed fields - same as table column fields, as in the above example

APIs for inherited roles:
----------------------

1. `add_inherited_role`

`add_inherited_role` is the [metadata API](https://hasura.io/docs/1.0/graphql/core/api-reference/index.html#schema-metadata-api) to create a new inherited role. It accepts two arguments

`role_name`: the name of the inherited role to be added (String)
`role_set`: list of roles that need to be combined (Array of Strings)

Example:

```json
{
  "type": "add_inherited_role",
  "args": {
      "role_name":"combined_user",
      "role_set":[
          "user",
          "user1"
      ]
  }
}
```

After adding the inherited role, the inherited role can be used like single roles like earlier

Note:

An inherited role can only be created with non-inherited/singular roles.

2. `drop_inherited_role`

The `drop_inherited_role` API accepts the name of the inherited role and drops it from the metadata. It accepts a single argument:

`role_name`: name of the inherited role to be dropped

Example:

```json

{
  "type": "drop_inherited_role",
  "args": {
      "role_name":"combined_user"
  }
}
```

Metadata
---------

The derived roles metadata will be included under the `experimental_features` key while exporting the metadata.

```json
{
  "experimental_features": {
    "derived_roles": [
      {
        "role_name": "manager_is_employee_too",
        "role_set": [
          "employee",
          "manager"
        ]
      }
    ]
  }
}
```

Scope
------

Only postgres queries and subscriptions are supported in this PR.

Important points:
-----------------

1. All columns exposed to an inherited role will be marked as `nullable`, this is done so that cell value nullification can be done.

TODOs
-------

- [ ] Tests
   - [ ] Test a GraphQL query running with a inherited role without enabling inherited roles in experimental features
   - [] Tests for aggregate queries, limit, computed fields, functions, subscriptions (?)
   - [ ] Introspection test with a inherited role (nullability changes in a inherited role)
- [ ] Docs
- [ ] Changelog

Co-authored-by: Vamshi Surabhi <6562944+0x777@users.noreply.github.com>
GitOrigin-RevId: 3b8ee1e11f5ceca80fe294f8c074d42fbccfec63
2021-03-08 11:15:10 +00:00
..
agg_perm [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
aggregations server: add type information to aggregates and stringify them (closes #5704) 2021-01-18 13:52:51 +00:00
allowlist [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
basic server: support ltree operators (close #625) 2021-02-25 11:06:49 +00:00
boolexp server: support ltree operators (close #625) 2021-02-25 11:06:49 +00:00
caching [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
computed_fields [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
custom_schema [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
enums [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
functions server: support tracking of custom functions which return single row 2021-02-03 14:07:30 +00:00
limits [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
offset [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
order_by [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
permissions [Preview] Inherited roles for postgres read queries 2021-03-08 11:15:10 +00:00
relay [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00
v1alpha1/errors [server] coalesce multiple run_sql calls in tests (#270) 2021-01-06 16:07:22 +00:00