auto-update: make output more user friendly

The rather raw and scarce output of `podman auto-update` has been a
thorn in my eyes for a longer while.  So far, Podman would only print
updated systemd units, one per line, without further formatting.

Motivated by issue #9949 which is asking for some more useful
information in combination with a dry-run feature, I sat down and
reflected which information may come in handy.

Running `podman auto-update` will now look as follows:

```
$ podman auto-update
Trying to pull [...]

UNIT                    CONTAINER            IMAGE                   POLICY      UPDATED
container-test.service  08fd34e533fd (test)  localhost:5000/busybox  registry    false
```

Also refactor the spaghetti code in the backend a bit to make it easier
to digest and maintain.

For easier testing and for the sake of consistency with other commands
listing output, add a `--format` flag.

The man page will get an overhaul in a follow up commit.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/test/system/250-systemd.bats b/test/system/250-systemd.bats
index 4ea192009..aafe385c8 100644
--- a/test/system/250-systemd.bats
+++ b/test/system/250-systemd.bats
@@ -119,7 +119,7 @@ function service_cleanup() {
     # Run auto-update and check that it restarted the container
     run_podman commit --change "CMD=/bin/bash" $cname $IMAGE
     run_podman auto-update
-    is $output $SERVICE_NAME "autoupdate local restarted container"
+    is "$output" ".*$SERVICE_NAME.*" "autoupdate local restarted container"
 
     # All good. Stop service, clean up.
     service_cleanup