Concepts - Header management

Last updated: Sep 5, 2023 2 minutes read.

With Tyk v5.2 the possibilities of managing headers for Universal Data Graph and all associated data sources have been extended.

Global headers for UDG

Global headers can be configured via Tyk API Definition. The correct place to do that is within graphql.engine.global_headers section. For example:

{
    "graphql": {
        "engine": {
            "global_headers": [
                {
                    "key": "global-header",
                    "value": "example-value"
                },
                {
                    "key": "request-id",
                    "value": "$tyk_context.request_id"
                }
            ]
        }
    }
}

Global headers now have access to all request context variables.

By default, any header that is configured as a global header, will be forwarded to all data sources of the UDG.

Data source headers

Data source headers can be configured via Tyk API Definition and via Tyk Dashboard UI. The correct place to do that is within graphql.engine.datasources.config.headers section. For example:

{
    "engine": {
        "data_sources": [
            {
                "config": {
                    "headers": {
                        "data-source-header": "data-source-header-value",
                        "datasource1-jwt-claim": "$tyk_context.jwt_claims_datasource1"
                    }
                }
            }
        ]
    }
}

Data source headers now have access to all request context variables.

Headers priority order

If a header has a value at the data source and global level, then the data source value takes precedence.

For example for the below configuration:

{
    "engine": {
        "data_sources": [
            {
                "config": {
                    "headers": {
                        "example-header": "data-source-value",
                        "datasource1-jwt-claim": "$tyk_context.jwt_claims_datasource1"
                    }
                }
            }
        ],
        "global_headers": [
          {
              "key": "example-header",
              "value": "global-header-value"
          },
          {
              "key": "request-id",
              "value": "$tyk_context.request_id"
          }
      ]
    }
}

The example-header header name is used globally and there is also a data source level header, with a different value. Value data-source-value will take priority over global-header-value, resulting in the following headers being sent to the data source:

Header name	Header value	Defined on level
example-header	data-source-value	data source
datasource1	$tyk_context.jwt_claims_datasource1	data source
request-id	$tyk_context.request_id	global