Add direct group dependency proxy env variable

Add CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX
predefined environment variable to projects.

Changelog: added

app/models/project.rb

@@ -2093,6 +2093,10 @@ def dependency_proxy_variables
         # Docker doesn't allow. The proxy expects it to be downcased.
         value: "#{Gitlab.host_with_port}/#{namespace.root_ancestor.path.downcase}#{DependencyProxy::URL_SUFFIX}"
       )
+      variables.append(
+        key: 'CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX',
+        value: "#{Gitlab.host_with_port}/#{namespace.full_path.downcase}#{DependencyProxy::URL_SUFFIX}"
+      )
     end
   end

doc/ci/variables/predefined_variables.md

@@ -41,7 +41,8 @@ There are also [Kubernetes-specific deployment variables](../../user/project/clu
 | `CI_CONFIG_PATH`                         | 9.4    | 0.5    | The path to the CI/CD configuration file. Defaults to `.gitlab-ci.yml`. Read-only inside a running pipeline. |
 | `CI_DEBUG_TRACE`                         | all    | 1.7    | `true` if [debug logging (tracing)](index.md#debug-logging) is enabled. |
 | `CI_DEFAULT_BRANCH`                      | 12.4   | all    | The name of the project's default branch. |
-| `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX` | 13.7   | all    | The image prefix for pulling images through the Dependency Proxy. |
+| `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX` | 13.7   | all    | The top-level group image prefix for pulling images through the Dependency Proxy. |
+| `CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX` | 14.3   | all    | The direct group image prefix for pulling images through the Dependency Proxy. |
 | `CI_DEPENDENCY_PROXY_PASSWORD`           | 13.7   | all    | The password to pull images through the Dependency Proxy. |
 | `CI_DEPENDENCY_PROXY_SERVER`             | 13.7   | all    | The server for logging in to the Dependency Proxy. This is equivalent to `$CI_SERVER_HOST:$CI_SERVER_PORT`. |
 | `CI_DEPENDENCY_PROXY_USER`               | 13.7   | all    | The username to pull images through the Dependency Proxy. |

doc/user/packages/dependency_proxy/index.md

@@ -94,8 +94,11 @@ Proxy.
 > - The prefix for group names containing uppercase letters was [fixed](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/54559) in GitLab 13.10.
 Runners log in to the Dependency Proxy automatically. To pull through
-the Dependency Proxy, use the `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX`
-[predefined CI/CD variable](../../../ci/variables/predefined_variables.md):
+the Dependency Proxy, use one of the [predefined variables](../../../ci/variables/predefined_variables.md):
+
+- `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX` pulls through the top-level group.
+- `CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX` pulls through the subgroup, or direct group the
+  project exists in.
 Example pulling the latest alpine image:
@@ -109,7 +112,10 @@ There are other additional predefined CI/CD variables you can also use:
 - `CI_DEPENDENCY_PROXY_USER`: A CI/CD user for logging in to the Dependency Proxy.
 - `CI_DEPENDENCY_PROXY_PASSWORD`: A CI/CD password for logging in to the Dependency Proxy.
 - `CI_DEPENDENCY_PROXY_SERVER`: The server for logging in to the Dependency Proxy.
-- `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX`: The image prefix for pulling images through the Dependency Proxy.
+- `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX`: the image prefix for pulling images through the
+  dependency proxy from the top-level group.
+- `CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX`: the image prefix for pulling images through the
+  dependency proxy from the direct group or subgroup that the project belongs to.
 `CI_DEPENDENCY_PROXY_SERVER` and `CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX`
 include the server port. If you explicitly include the Dependency Proxy

spec/models/ci/build_spec.rb

@@ -2632,6 +2632,10 @@
             value: "#{Gitlab.host_with_port}/#{project.namespace.root_ancestor.path.downcase}#{DependencyProxy::URL_SUFFIX}",
             public: true,
             masked: false },
+          { key: 'CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX',
+            value: "#{Gitlab.host_with_port}/#{project.namespace.full_path.downcase}#{DependencyProxy::URL_SUFFIX}",
+            public: true,
+            masked: false },
           { key: 'CI_API_V4_URL', value: 'http://localhost/api/v4', public: true, masked: false },
           { key: 'CI_PIPELINE_IID', value: pipeline.iid.to_s, public: true, masked: false },
           { key: 'CI_PIPELINE_SOURCE', value: pipeline.source, public: true, masked: false },