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Access control - authorisation overview

Authorisation​

Authorisation is the process by which you apply specific permissions to resources. Only users who pass the permission criteria for the resource have access.

The server of a Genesis application provides three main types of resource entry point for clients to instigate events or to query data.

  • Data Servers
  • Event Handlers
  • Request Servers

All these services can be permissioned using a permissioning GPAL syntax block in the GPAL configuration associated with the service.

Permissioning block snippet

// this example would be enclosed within a resource (eg DataServer Query) specific block
permissioning {

    // 'permission Code' list, users must have the permission to access the enclosing resource
    permissionCodes = listOf("TRADER", "SUPPORT")

    // Permission at the row and/or column level for a grid or table of data
    auth("TRADE_VISIBILITY") {
        TRADE_VIEW.TRADE_ID
    }

    // customPermissions allow you to write custom code to determine user access.
    customPermissions { message ->
      customFunction(message.userName)
    }
}

Global and specific permissioning​

Here's what you need to know:

  • A permissioning block can exist inside a resource (requestReply, query or eventHandler) definition. In this case, it applies only to that resource definition. This is specific permissioning.
  • Alternatively, you can specify a permissioning block outside any resource in the file. This is global permissioning. If you do this, the permissioning applies by default to all the resources in the file. However, any permissioning block inside a specific resource overrides this default.
  • The permissioning block at the global level can only contain permissionCodes, as the auth block is based on each individual resource definition and the customPermissions block provides access to the incoming message.
  • Every request that comes into a Genesis server will include the username of an authenticated user. Non-authenticated users will not have access to or visibility of the Genesis services.

In the example below, the block applies to a specific requestReply within a Request Server:

requestReplies {
    requestReply("MARKET_INSTRUMENTS", INSTRUMENT_DETAILS) {
        permissioning {
            permissionCodes = listOf("TRADER")
        }
    }
}

In the example below, the global permissioning applies by default to the first three requestReply blocks in the Request Server. However, the fourth requestReply block has a specific permissioning block requiring the user to be in the list SUPER.

requestReplies {
    permissioning {
        permissionCodes = listOf("TRADER")
    }
    requestReply("ALLOCATION CODES", ALLOCATION CODES)

    requestReply("ALL_COUNTERPARTIES", ALL_COUNTERPARTIES)

    requestReply("ALL_BROKERS", ALL_BROKERS)

    requestReply("ALL_TRADES", INSTRUMENT_DETAILS) {
        permissioning {
            permissionCodes = listOf("SUPER")
        }
    }
}

Permissioning sub-blocks​

There are three main sub-blocks to the permissioning block that can be applied to suit your needs:

  • PermissionCodes list
  • auth sub-block
  • customPermissions function

PermissionCodes list​

Here is a simple example:

permissionCodes = listOf("TRADER", "SUPPORT")

Where a PermissionCodes list is defined, the user must have one of the listed permission codes to access the GPAL enclosed resource. If the user does not belong to one of the listed permission codes, the subsequent auth block will essentially be ignored.

To enable a user to have access to a specific permissionCode:

  • the permissionCode must be defined in the RIGHT table
  • the code must be linked to an entry in the PROFILE_RIGHT table
  • the code must be linked to a PROFILE that is associated with the USER from PROFILE_USER

The AUTH_MANAGER process will populate the RIGHT_SUMMARY table based on the table configurations above. This table ultimately drives the available permission codes for all users in the system.

These tables are part of the Genesis Auth module.

Auth sub-block​

Here is an example:

        auth(mapName = "ENTITY_VISIBILITY") {
            POSITION.COUNTERPARTY_ID
        }

Where an auth sub-block is defined, you can provide further fine-grained control of what data, at the row level, is returned to a specific user. If it is not defined, then all data is returned for the enclosing resource, assuming permissionCodes are not restricting access.

The reference POSITION.COUNTERPARTY_ID in the auth snippet above refers to the COUNTERPARTY_ID field from the POSITION object that is supplied as a parameter to the resource request. This value is used as a key into a specific AuthCache, identified by entity name. In this example, that is "ENTITY_VISIBILITY"

Each AuthCache will map Entity Id (in our example, COUNTERPARTY_ID from the POSITION object) to a Set of users.

The mapName parameter refers to a specific permission entity defined on the server via the auth-permission.xml file. For example:

 <dynamicPermissions>
  <!-- other tags removed for brevity -->
   <entity name="ENTITY_VISIBILITY"
              tableName="USER_COUNTERPARTY_MAP"
              maxEntries="20000"
              idField="USER_NAME">
    <!-- further structure with groovy expression to define programmatic control and define an AuthMap -->
    </entity>
  <!-- additional entities would go here-->
</dynamicPermissions>

In cases where you do not require the auth map and just want to define a where clause, you can omit it from the definition. For example:

        auth {
            where {
                ...
            }
        }

Custom permissions function​

Here is a simple example for a dataserver block:

customPermissions { message ->
  val userAttributes = entityDb.get(UserAttributes.byUserName(message.userName))
  userAttributes?.accessType == AccessType.ALL
}

The customPermissions function acts as an additional permissions check which works in a similar way to permissionCodes. If this function returns true, the user will be able to access the resource, otherwise the request will be rejected. The example above performs a database lookup on the "USER_ATTRIBUTES" table, and will only return true if the user has AccessType.ALL.

The main advantage of declaring a customPermissions function is that you can write any sort of custom code within it. This can make integration with existing entitlement systems a much easier task, as it means you can avoid replicating the correct rights and profiles hierarchy within the Genesis database.

All customPermissions functions give you access to a property called entityDb that provides access to the database API. Additionally, customPermissions provides a function parameter that contains the request message itself. This type of this message will vary depending on where the customPermissions function has been declared:

  • Data Server - the parameter will be of type Details<DataLogon>. This message contains all the options specified by the client when attempting to create a dataserver subscription, as well as the username.
  • Request Server - the parameter will be of type GenesisSet, as Request Server definitions can heavily customise the inbound metadata, and it might not necessarily match any pre-existing generated entity.
  • Custom Request Server - the parameter will be of type Request<V> where V is the class used to define the inbound message. More information about custom Request Servers can be found here.
  • Event Handler - the parameter will be of type Event<V> where V is the class used to define the inbound message. This parameter is also present in the onValidate and onCommit GPAL Event Handler functions.

Generic permissions​

Generic permissions is a term used to name the optional permissions configuration that is available for a Genesis application; this is included as part of the Genesis Auth Module.

To fully activate Generic permissions, you need to add the following values to your product system definition file locate under the config project (for example alpha-system-definition.kts) before you run genesisInstall.

These values specify which table column will be used to associate users with entities for fine-grained row permissions.

systemDefinition {
    global {
        item(name = "ADMIN_PERMISSION_ENTITY_TABLE", value = "COUNTERPARTY")
        item(name = "ADMIN_PERMISSION_ENTITY_FIELD", value = "COUNTERPARTY_ID")
    }
}

Note these important details:

  • These values will add the specified field to the USER_ATTRIBUTES table as a required field and create a new table called USER_COUNTERPARTY_MAP (in the case of our example), which will be suitably populated by the AUTH_MANAGER process on a real-time basis.

  • The USER_COUNTERPARTY_MAP table is referenced in the ENTITY_VISIBILITY entity in the auth-permission.templt.xml file. This file is a Genesis mustache template that is processed when genesisInstall is run, using entries from system-definition.

  • When new users are created in the Genesis user entity management, a required field, COUNTERPARTY, is presented to the operating user. This limits users to belonging to a single counterparty.

A user can define additional permissions.xml files. For example, you could define something like order-management-permissions.xml, with an order management system auth implementation, and it will be read by AUTH_PERMS process on start-up.

There are two kinds of permission entity defined by Generic Permissions in the auth-permission.templt.xml file:

  • USER_VISIBILITY - an AuthCache that determines which user is visible to which user; this is driven by which users are associated for the entity. Using our example, if two users are both in the same counterparty, then they should be viewable to each other.

  • ENTITY_VISIBILITY - an AuthCache that determines if a user has access to a particular entity; in our example, if the user is permissioned for a particular counterparty, then that user will be able to see the associated row data for that counterparty.