RHIDP-8828: Injecting resources for backstage containers

modules/configuring/proc-mounting-additional-files-in-your-custom-configuration-using-rhdh-operator.adoc

@@ -3,7 +3,9 @@
 [id="mounting-additional-files-in-your-custom-configuration-using-rhdh-operator"]
 = Mounting additional files in your custom configuration by using the {product} Operator
 
-You can use the {product-short} Operator to mount extra files, such as a ConfigMap or Secret, to the container in a preferred location.
+You can mount extra files, such as a ConfigMaps, Secrets or PVCs and inject environment variables into your {product-very-short} containers by configuring the `extraFiles` and `extraEnvs` fields in your `{product-custom-resource-type}` custom resource (CR).
+
+By default, files mount only to the `backstage-backend` container, but you can target other containers explicitly using the `containers` field.
 
 The `mountPath` field specifies the location where a ConfigMap or Secret is mounted.
 The behavior of the mount, whether it includes or excludes a `subPath`, depends on the specification of the `key` or `mountPath` fields.
@@ -55,27 +57,124 @@ StringData:
 +
 For more information, see xref:provisioning-your-custom-configuration[Provisioning and using your custom {product} configuration].
 
-. Set the value of the `configMaps name` to the name of the ConfigMap or `secrets name` to the name of the Secret in your `{product-custom-resource-type}` CR.
-For example:
+. Apply the configuration to your `{product-custom-resource-type}` CR by setting the values for `extraFiles` and `extraEnvs`.
 +
-[source,yaml,subs="+attributes,+quotes"]
+[source,yaml]
 ----
 spec:
   application:
     extraFiles:
-      mountPath: /my/path
+      mountPath: _<default_mount_path>_
       configMaps:
-        - name: {my-extra-file-configmap}
-          key: file12.txt
-          mountPath: /my/my-rhdh-config-map/path
+        - name: _<configmap_name_all_entries>_
+        - name: _<configmap_name_single_key>_
+          key: _<specific_file_key>_
+          containers:
+            - "*"
+        - name: _<configmap_name_custom_path>_
+          mountPath: _<custom_cm_mount_path>_
+          containers:
+            - backstage-backend
+            - install-dynamic-plugins
       secrets:
-        - name: `_<my_product_secrets>_`
-          key: secret11.txt
-          mountPath: /my/my-rhdh-secret/path
+        - name: _<secret_name_single_key>_
+          key: _<specific_secret_key>_
+          containers:
+            - install-dynamic-plugins
+        - name: _<secret_name_custom_path>_
+          mountPath: _<custom_secret_mount_path>_
+      pvcs:
+        - name: _<pvc_name_default_path>_
+        - name: _<pvc_name_custom_path>_
+          mountPath: _<custom_pvc_mount_path>_
 
+    extraEnvs:
+      configMaps:
+        - name: _<configmap_name_env_var>_
+          key: _<env_var_key>_
+          containers:
+            - "*"
+      secrets:
+        - name: _<secret_name_all_envs>_
+      envs:
+        - name: _<static_env_var_name>_
+          value: "_<static_env_var_value>_"
+          containers:
+           - install-dynamic-plugins
 ----
+where:
+
+`spec.application.extraFiles.mountPath`:: Specifies the default base mount path for files if no specific `mountPath` is set for a resource (for example, `/<default_mount_path>`).
+`spec.application.extraFiles.configMaps.name`:: Mounts all entries from `<configmap_name_all_entries>` to the default mount path.
+`spec.application.extraFiles.configMaps.key`:: Mounts **only the specified key (for example, `<specific_file_key>.txt`) from the ConfigMap.
+`spec.application.extraFiles.configMaps.containers`:: Targets all containers (`"*"`) for mounting.
+`spec.application.extraFiles.configMaps.mountPath`:: Overrides the default and mounts all ConfigMap entries as a directory at the specified path (for example, `/<custom_cm_mount_path>`).
+`spec.application.extraFiles.secrets.key`:: Mounts only a specific key from the Secret.
+`spec.application.extraFiles.secrets.mountPath`:: Overrides the default and mounts all Secret entries as a directory at the specified path (for example, `/<custom_secret_mount_path>`).
+`spec.application.extraFiles.pvcs.name`:: Mounts the PVC to the default mount path, appending the PVC name (for example, `/<default_mount_path>/<pvc_name_default_path>`).
+`spec.application.extraFiles.pvcs.mountPath`:: Overrides the default and mounts the PVC to the specified path (for example, `/<custom_pvc_mount_path>`).
+`spec.application.extraEnvs.configMaps.containers`:: Injects the specified ConfigMap key as an environment variable into all containers (`"*"`).
+`spec.application.extraEnvs.secrets.name`:: Injects all keys from the Secret as environment variables into the default container.
+`spec.application.envs.containers`:: Targets only the listed container for the static environment variable injection.
 +
 [NOTE]
 ====
-`_<my_product_secrets>_` is your preferred {product-short} secret name, specifying the identifier for your secret configuration within {product-short}.
+**Container Targeting:**
+* **No** or an empty `containers` field: Targets the `backstage-backend` container (default).
+* `*` (asterisk): Targets all containers.
+* Explicit container names (e.g., `install-dynamic-plugins`): Targets only the listed containers.
 ====
+
+.Verification
+
+Verify that the files are mounted with the following correct paths and container targets:
+
+[cols="1,2,3,2", options="header"]
+|===
+| Resource | Target Type | Path(s) or Name(s) | Container(s)
+
+| ConfigMap (`<configmap_name_all_entries>`)
+| File
+| `/<default_mount_path>/<file_1_key>`, `/<default_mount_path>/<file_2_key>`
+| `backstage-backend`
+
+| ConfigMap (`<configmap_name_single_key>`)
+| File
+| `/<default_mount_path>/<specific_file_key>.txt`
+| All
+
+| ConfigMap (`<configmap_name_custom_path>`)
+| Directory
+| `/<custom_cm_mount_path>/`
+| `backstage-backend`, `install-dynamic-plugins`
+
+| Secret (`<secret_name_single_key>`)
+| File
+| `/<default_mount_path>/<specific_secret_key>.txt`
+| `install-dynamic-plugins`
+
+| Secret (`<secret_name_custom_path>`)
+| Directory
+| `/<custom_secret_mount_path>/`
+| `backstage-backend`
+
+| PVC (`<pvc_name_default_path>`)
+| Directory
+| `/<default_mount_path>/<pvc_name_default_path>`
+| `backstage-backend`
+
+| ConfigMap (`<configmap_name_env_var>`)
+| Env Var
+| `<env_var_key>`
+| All
+
+| Secret (`<secret_name_all_envs>`)
+| Env Var
+| `<secret_key_a>`, `<secret_key_b>`
+| `backstage-backend`
+
+| CRD (`envs`)
+| Env Var
+| `<static_env_var_name> = <static_env_var_value>`
+| `install-dynamic-plugins`
+|===