TFS 2017 | VSTS
Library is a collection of shared build and release assets for a team project. Assets defined in a library can be used in multiple build and release definitions of the team project. The Library tab can be accessed directly in the Build & Release hub in Visual Studio Team Services (VSTS) and Team Foundation Server (TFS).
Variable groups are available to only release definitions in VSTS and TFS 2017 at present. Task groups and service endpoints are available to build and release definitions in TFS 2015, TFS 2017, and VSTS.
All assets defined in the Library tab share a common security model. You can control who can define new items in a library, and who can use an existing item. Roles are defined for library items, and membership of these roles governs the operations you can perform on those items.
|Role on a library item||Purpose|
|Reader||Members of this role can view the item.|
|User||Members of this role can use the item when authoring build or release definitions. For example, you must be a 'User' for a variable group to be able to use it in a release definition.|
|Administrator||In addition to all the above operations, members of this role can manage membership of all other roles for the item. The user that created an item is automatically added to the Administrator role for that item.|
The security settings for the Library tab control access for all items in the library. Role memberships for individual items are automatically inherited from those of the Library node. In addition to the three roles listed above, the Creator role on the library defines who can create new items in the library, but cannot be used to manage permissions for other users. By default, the following groups are added to the Administrator role of the library: Build Administrators, Release Administrators, and Project Administrators.