What it is

CLI tool to patch Hasura metadata json file with needed objects or with another Hasura metadata file. You can use it to deploy complex CI/CD flows for applications, which are using Hasura on a backend.

Why it is useful

If you use different environments, you likely have different webhooks in each environment. With this tool you can describe needed metadata for each webhook separately and finally merge them all when you need to deploy your release. Such approach gives an ability to several people to develop different webhooks independently.

Requirements

• Python 3.6 or higher
• requirements.txt

How it works

Syntax

python main.py -r remote_schemas -r actions -r custom_types -r event_triggers -s dev_metadata.json -m prod_metadata.json -o out.json

Find all the syntax by python main.py --help

Supported operations

Merge

Default mode. Use it to merge needed Hasura objects from a mixin file to a source metadata file.

Replace -r

Use it to define, which objects should be fully replaced in a source metadata file by objects from a mixin.

For example, if a mixin file is another Hasura metadata file and you call

python main.py -r event_triggers -s dev_metadata.json -m prod_metadata.json -o out.json

then:

1. All the metadata objects from prod_metadata.json will be mixed in to metadata from dev_metadata.json. This means that if object does not exist in dev_metadata.json, it will be created, but if exists it will be replaced with new object from a mixin file prod_metadata.json.
2. All the event triggers will be removed for all the tables in the resulted metadata from the previous step.
3. New event triggers from prod_metadata.json will be inserted instead.
4. The result metadata goes to out.json.

Typical Hasura metadata release flow

1. Export metadata in json format from Hasura in dev environment, which should be deployed to production.
2. Export metadata in json format from Hasura in current production environment.
3. Run patcher with source json file from dev and mixin file from production.
4. Run patcher with output json file from previous step and mixin files with new Hasura objects to deploy.
5. The last output file is your new Hasura metadata for production environment.

Points 1-3 are needed to migrate new tables and permissions from dev environment, since they are not supported by this patcher for now.

Supported Hasura objects

• Event triggers
• Remote schemas
• Actions
• Custom types (object types and input types)
• Sources
• Tables
• Table permissions

Hasura objects format to patch

Event trigger

{
    "type": "event_trigger",
    "object": {
        "name": "myEventTrigger",
        "table": {
            "schema": "core",
            "name": "some_table"
        },
        "definition": {
            "enable_manual": false,
            "insert": {
                "columns": "*"
            },
            "update": {
                "columns": []
            }
        },
        "retry_conf": {
            "num_retries": 0,
            "interval_sec": 10,
            "timeout_sec": 60
        },
        "webhook": "https://mywebhook.url",
        "config": "1.2.3",
        "headers": [{
            "name": "token",
            "value": "%TOKEN_ENV%"
        }],
        "comment": "0.1.0"
    }
}

Action

{
  "type": "action",
  "object": {
      "name": "myAction",
      "definition": {
        "handler": "https://mywebhook.url",
        "output_type": "myOutputType",
        "headers": [
          {
            "name": "Authorization",
            "value_from_env": "AUTHORIZATION_HEADER"
          }
        ],
        "arguments": [
          {
            "name": "value",
            "type": "String!"
          }
        ],
        "type": "mutation",
        "kind": "synchronous"
      },
      "permissions": [
        {
          "role": "user"
        }
      ],
      "comment": "0.1.0"
  }
}

Custom type

{
    "type": "custom_type",
    "object": {
      "name": "myCustomType",
      "fields": [
        {
          "name": "affected_rows",
          "type": "Int!"
        }
      ]
    }
}

Remote schema

{
    "type": "remote_schema",
    "object": {
      "name": "myRemoteSchema",
      "definition": {
        "url": "https://myschema.url/graphql",
        "timeout_seconds": 60,
        "forward_client_headers": false,
        "headers": [
          {
            "name": "Authorization",
            "value_from_env": "AUTHORIZATION_HEADER"
          }
        ]
      },
      "comment": "0.1.0"
    }
}