Schema/Metadata API Reference: Manage metadata¶

Table of contents

Introduction
export_metadata
replace_metadata
reload_metadata
clear_metadata
get_inconsistent_metadata
drop_inconsistent_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",
    "args": "<metadata-as-json-object>"
}

Args syntax¶

Args should be the JSON object which is same as the output of export_metadata.

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
    }
}

Args syntax¶

Key	Required	Schema	Description
reload_remote_schemas	false	Boolean	If set to `true`, all remote schemas’ (including inconsistent ones) cached GraphQL schemas are refreshed (default: `false`)

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": {}
}

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