Give auto-update ability to use per-container authfile specified by…

… label.

Signed-off-by: Ondřej Kraus <[email protected]>

docs/source/markdown/podman-auto-update.1.md

@@ -13,6 +13,8 @@ If the label is present and set to "image", Podman reaches out to the correspond
 An image is considered updated if the digest in the local storage is different than the one of the remote image.
 If an image must be updated, Podman pulls it down and restarts the systemd unit executing the container.
 
+If "io.containers.autoupdate.authfile" label is present, Podman reaches out to corresponding authfile when pulling images.
+
 At container-creation time, Podman looks up the "PODMAN_SYSTEMD_UNIT" environment variables and stores it verbatim in the container's label.
 This variable is now set by all systemd units generated by `podman-generate-systemd` and is set to `%n` (i.e., the name of systemd unit starting the container).
 This data is then being used in the auto-update sequence to instruct systemd (via DBUS) to restart the unit and hence to restart the container.
@@ -35,7 +37,9 @@ environment variable. `export REGISTRY_AUTH_FILE=path`
 
 ```
 # Start a container
-$ podman run --label "io.containers.autoupdate=image" -d busybox:latest top
+$ podman run --label "io.containers.autoupdate=image" \
+    --label "io.containers.autoupdate.autfile=/some/authfile.json" \
+    -d busybox:latest top
 bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
 
 # Generate a systemd unit for this container

pkg/autoupdate/autoupdate.go

@@ -23,6 +23,10 @@ import (
 // container labels.
 const Label = "io.containers.autoupdate"
 
+// Label denotes the container label key to specify authfile in
+// container labels.
+const AuthfileLabel = "io.containers.autoupdate.authfile"
+
 // Policy represents an auto-update policy.
 type Policy string
 
@@ -144,6 +148,11 @@ func AutoUpdate(runtime *libpod.Runtime, options Options) ([]string, []error) {
 			if rawImageName == "" {
 				errs = append(errs, errors.Errorf("error auto-updating container %q: raw-image name is empty", ctr.ID()))
 			}
+			labels := ctr.Labels()
+			authFilePath, exists := labels[AuthfileLabel]
+			if exists {
+				options.Authfile = authFilePath
+			}
 			needsUpdate, err := newerImageAvailable(runtime, image, rawImageName, options)
 			if err != nil {
 				errs = append(errs, errors.Wrapf(err, "error auto-updating container %q: image check for %q failed", ctr.ID(), rawImageName))