From 59f31d86acdf54019b081ca86340d5c33dbcf3b9 Mon Sep 17 00:00:00 2001
From: Valentin Rothberg <rothberg@redhat.com>
Date: Thu, 15 Jul 2021 11:27:25 +0200
Subject: auto-update: add --dry-run

Add a --dry-run flag to `podman auto-update` which will look for new
images but won't perform any pull or restart any service or container.

The "UPDATED" column will now indicate the availability of a newer image
via "pending".

```
$ podman auto-update --dry-run
UNIT                    CONTAINER            IMAGE                   POLICY      UPDATED
container-test.service  08fd34e533fd (test)  localhost:5000/busybox  registry    false
```

Fixes: #9949
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
---
 docs/source/markdown/podman-auto-update.1.md | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

(limited to 'docs/source')

diff --git a/docs/source/markdown/podman-auto-update.1.md b/docs/source/markdown/podman-auto-update.1.md
index 4f2608be4..106b9b00a 100644
--- a/docs/source/markdown/podman-auto-update.1.md
+++ b/docs/source/markdown/podman-auto-update.1.md
@@ -41,6 +41,11 @@ If the authorization state is not found there, `$HOME/.docker/config.json` is ch
 
 Note: There is also the option to override the default path of the authentication file by setting the `REGISTRY_AUTH_FILE` environment variable. This can be done with **export REGISTRY_AUTH_FILE=_path_**.
 
+#### **--dry-run**=*true|false*
+
+Check for the availability of new images but do not perform any pull operation or restart any service or container.
+The `UPDATED` field indicates the availability of a new image with "pending".
+
 #### **--format**=*format*
 
 Change the default output format.  This can be of a supported type like 'json' or a Go template.
@@ -64,7 +69,7 @@ Autoupdate with registry policy
 ### Start a container
 $ podman run --label "io.containers.autoupdate=registry" \
     --label "io.containers.autoupdate.authfile=/some/authfile.json" \
-    -d busybox:latest top
+    -d --name=test registry.fedoraproject.org/fedora:latest sleep infinity
 bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
 
 ### Generate a systemd unit for this container
@@ -72,18 +77,23 @@ $ podman generate systemd --new --files bc219740a210455fa27deacc96d50a9e20516492
 /home/user/container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service
 
 ### Load the new systemd unit and start it
-$ mv ./container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service ~/.config/systemd/user
+$ mv ./container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service ~/.config/systemd/user/container-test.service
 $ systemctl --user daemon-reload
 
 ### If the previously created containers or pods are using shared resources, such as ports, make sure to remove them before starting the generated systemd units.
 $ podman stop bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
 $ podman rm bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
 
-$ systemctl --user start container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service
+$ systemctl --user start container-test.service
 
-### Auto-update the container
+### Check if a newer image is available
+$ podman auto-update --dry-run --format "{{.Image}} {{.Updated}}"
+registry.fedoraproject.org/fedora:latest   pending
+
+### Autoupdate the services
 $ podman auto-update
-[...]
+UNIT                    CONTAINER            IMAGE                                     POLICY      UPDATED
+container-test.service  08fd34e533fd (test)  registry.fedoraproject.org/fedora:latest  registry    false
 ```
 
 Autoupdate with local policy
-- 
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