spec: support supplementary GIDs

schema/types/app.go

@@ -22,15 +22,16 @@ import (
 )
 
 type App struct {
-	Exec             Exec           `json:"exec"`
-	EventHandlers    []EventHandler `json:"eventHandlers,omitempty"`
-	User             string         `json:"user"`
-	Group            string         `json:"group"`
-	WorkingDirectory string         `json:"workingDirectory,omitempty"`
-	Environment      Environment    `json:"environment,omitempty"`
-	MountPoints      []MountPoint   `json:"mountPoints,omitempty"`
-	Ports            []Port         `json:"ports,omitempty"`
-	Isolators        Isolators      `json:"isolators,omitempty"`
+	Exec                Exec           `json:"exec"`
+	EventHandlers       []EventHandler `json:"eventHandlers,omitempty"`
+	User                string         `json:"user"`
+	Group               string         `json:"group"`
+	SupplementaryGroups []int          `json:"supplementaryGroups,omitempty"`
+	WorkingDirectory    string         `json:"workingDirectory,omitempty"`
+	Environment         Environment    `json:"environment,omitempty"`
+	MountPoints         []MountPoint   `json:"mountPoints,omitempty"`
+	Ports               []Port         `json:"ports,omitempty"`
+	Isolators           Isolators      `json:"isolators,omitempty"`
 }
 
 // app is a model to facilitate extra validation during the

spec/aci.md

@@ -101,6 +101,10 @@ JSON Schema for the Image Manifest (app image manifest, ACI manifest), conformin
         ],
         "user": "100",
         "group": "300",
+        "supplementaryGids": [
+                400,
+                500
+        ],
         "eventHandlers": [
             {
                 "exec": [
@@ -221,6 +225,7 @@ JSON Schema for the Image Manifest (app image manifest, ACI manifest), conformin
 * **app** (object, optional) if present, defines the default parameters that can be used to execute this image as an application.
     * **exec** (list of strings, required) executable to launch and any flags (must be non-empty; the executable must be an absolute path within the app rootfs; ACE can append or override).  These strings are not evaluated in any way and environment variables are not substituted.
     * **user**, **group** (string, required) indicates either the username/group name or the UID/GID the app is to be run as (freeform string). The user and group values may be all numbers to indicate a UID/GID, however it is possible on some systems (POSIX) to have usernames that are all numerical. The user and group values will first be resolved using the image's own `/etc/passwd` or `/etc/group`. If no valid matches are found, then if the string is all numerical, it shall be converted to an integer and used as the UID/GID. If the user or group field begins with a "/", the owner and group of the file found at that absolute path inside the rootfs is used as the UID/GID of the process. Example values for the fields include `root`, `1000`, or `/usr/bin/ping`.
+    * **supplementaryGids** (list of unsigned integers, optional) indicates additional (supplementary) group IDs (GIDs) as which the app's processes should run.
     * **eventHandlers** (list of objects, optional) allows the app to have several hooks based on lifecycle events. For example, you may want to execute a script before the main process starts up to download a dataset or backup onto the filesystem. An eventHandler is a simple object with two fields - an **exec** (array of strings, ACE can append or override), and a **name** (there may be only one eventHandler of a given name), which must be one of:
         * **pre-start** - executed and must exit before the long running main **exec** binary is launched
         * **post-stop** - executed if the main **exec** process is killed. This can be used to cleanup resources in the case of clean application shutdown, but cannot be relied upon in the face of machine failure.