Schema/Metadata API Reference: Manage metadata¶

Introduction¶

APIs to manage Hasura metadata which is stored in hdb_catalog schema.

export_metadata¶

export_metadata is used to export the current metadata from the server as a JSON file.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "export_metadata",
    "args": {}
}

Response:

The response JSON will be the metadata object. The structure of the metadata object is just a JSON version of the metadata files generated by the CLI.

replace_metadata¶

replace_metadata is used to replace/import metadata into Hasura. Existing metadata will be replaced with the new one.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "replace_metadata",
    "version": 1 | 2
    "args": <replace-metadata-args>
}

{
    allow_inconsistent_metadata: Boolean
    metadata: metadata-object
}

HTTP/1.1 400 Bad Request

{
  "internal": [
    {
      "type": "remote_schema",
      "reason": "HTTP exception occurred while sending the request to http://localhost:5000/hello-graphql",
      "definition": {
        "definition": {
          "url": "http://localhost:5000/hello-graphql",
          "forward_client_headers": false
        },
        "name": "test",
        "permissions": [],
        "comment": "testing replace metadata with remote schemas"
      }
    }, ...
  ]
}

reload_metadata¶

reload_metadata should be used when there is a change in underlying Postgres database that Hasura should be aware of. Example: a new column is added to a table using psql and this column should now be added to the GraphQL schema.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "reload_metadata",
    "args": {
        "reload_remote_schemas": true
    }
}

clear_metadata¶

clear_metadata can be used to reset the state of Hasura – clean the current state by forgetting the tables tracked, relationships, permissions, event triggers etc.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type" : "clear_metadata",
    "args": {}
}

get_inconsistent_metadata¶

get_inconsistent_metadata can be used to fetch all inconsistent metadata objects.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type": "get_inconsistent_metadata",
    "args": {}
}

Response:

[
    {
        "definition": {
            "using": {
                "foreign_key_constraint_on": {
                    "column": "author_id",
                    "table": "article"
                }
            },
            "name": "articles",
            "comment": null,
            "table": "author"
        },
        "reason": "table \"article\" does not exist",
        "type": "array_relation"
    },
    {
        "definition": {
            "using": {
                "foreign_key_constraint_on": "author_id"
            },
            "name": "author",
            "comment": null,
            "table": "article"
        },
        "reason": "table \"article\" does not exist",
        "type": "object_relation"
    },
    {
        "definition": "article",
        "reason": "no such table/view exists in postgres : \"article\"",
        "type": "table"
    }
]

drop_inconsistent_metadata¶

drop_inconsistent_metadata can be used to purge all inconsistent objects from the metadata.

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
    "type": "drop_inconsistent_metadata",
    "args": {}
}