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Contribution model

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Azure DevOps Services | Azure DevOps Server 2022 - Azure DevOps Server 2019

Extensions add new capabilities into the system by providing contributions and by defining ways for other extensions to plug in to them. A contribution type defines something that can be added to the system. A contribution is a specific instance of a contribution type. For example, hub is a contribution type defined by a core Microsoft-provided extension. The Explorer hub under the Build hub group is a specific contribution of type hub.

For more information, see the following references:

Contribution types

A contribution type defines a contract that all contributions to the system of that type must adhere to. A contribution type can also extend from another contribution type. The following examples of contribution types define the properties set by instances of that type:

  • hub
  • action
  • build-task

Each property definition specifies the following aspects:

  • Property type, for example string, boolean, and so on.
  • Whether the property is required
  • Default value, if not specified by a contribution (optional).

Example

Here's an example of a contribution type declaration in an extension manifest:

{
    ...
    "contributionTypes": [
        {
            "id": "hub",
            "name": "Web Access Hub",
            "description": "A hub that appears in the hubs menu at the top of web pages.",
            "properties": {
                "name": {
                    "description": "The text to display for the hub",
                    "type": "string",
                    "required": true
                },
                "uri": {
                    "description": "URI of the contents of the hub page",
                    "type": "string",
                    "required": true
                },
                "order": {
                    "description": "An optional ordering value which can indicate in which position to place the hub within the hub group",
                    "type": "integer"
                }
				...
            }
        }
    ]
}

Contributions

A contribution is an instance of a contribution type. For example, the Queries hub under the Work hub group is a contribution of type hub and the Publish Test Results build task is a contribution of type build-task.

All contributions must specify a type and specify values for any properties required by that contribution type.

Example

Here's an example of a hub contribution declaration in an extension manifest:

{
    "contributions": [
        {
            "id": "build-explorer-hub",
            "type": "ms.vss-web.hub",
            "targets": [
                ".build-hub-group"
            ],
            "properties": {
                "name": "Explorer",
                "uri": "/_build",
                "order": 22
            }
        }
    ]
}

Target contributions

A contribution can target one or more other contributions, which creates a relationship between the contribution and each of its targets. The system can discover contributions for the target at runtime. For example, a hub contribution (Explorer) might target a specific hub-group contribution (Build).

{
    "id": "build-explorer-hub",
    "type": "ms.vss-web.hub",
    "targets": [
        ".build-hub-group"
    ]
}

When the hub group renders, the system can query for all hub contributions that target the hub group to know which hubs to render.

Identify contributions and types

Every contribution and contribution type must have a unique ID within the extension it's declared in.

A full contribution identifier includes the following items, which you separate with a dot . :

  • Publisher ID
  • Extension ID
  • Contribution/type ID

For example: ms.vss-web.hub is the full identifier for the following contribution:

  • Publisher ID: ms
  • Extension ID: vss-web
  • Contribution/type ID: hub

You can use relative contribution references within an extension manifest for a contribution's reference to another contribution or contribution type within that same extension. In this case, the publisher and extension IDs aren't included, and the ID is a dot . followed by the contribution ID. For example, .hub may be used within the vss-web extension mentioned previously as a shortcut for ms.vss-web.hub.