Merge ~paelzer/ubuntu/+source/landscape-client:lp-1893716-reduce-login-overhead-JAMMY into ubuntu/+source/landscape-client:ubuntu/jammy-devel

[Christian Ehrhardt ]

[Christian Ehrhardt  (paelzer)]

PPA: https://launchpad.net/~paelzer/+archive/ubuntu/lp-1893716-recude-login-overhead-jammy

Details and test cases in the bug (linked above).

[Christian Ehrhardt  (paelzer)]

Added Simon for landscape POV ack.

[Christian Ehrhardt  (paelzer)]

Also send to upstream-landscape at
https://github.com/CanonicalLtd/landscape-client/pull/109

[Christian Ehrhardt  (paelzer)]

See the ongoing discussion in https://github.com/CanonicalLtd/landscape-client/pull/109
I'll refresh this PR and the PPA once this settled.

[Christian Ehrhardt  (paelzer)]

PPA and Branch updated to the interim state of the upstream discussion.

77318e8... by Christian Ehrhardt  on 2022-04-01

changelog: avoid too frequent expensive operations (LP: #1893716)

Signed-off-by: Christian Ehrhardt <email address hidden>

[Simon Poirier (simpoir)]

+1 thanks for that change.

review: Approve

[Christian Ehrhardt  (paelzer)]

Thanks.
Merged upstream in https://github.com/CanonicalLtd/landscape-client/pull/109

Uploading to Jammy

Uploading to ubuntu (via ftp to upload.ubuntu.com):
  Uploading landscape-client_19.12-0ubuntu13.dsc: done.
  Uploading landscape-client_19.12-0ubuntu13.debian.tar.xz: done.
  Uploading landscape-client_19.12-0ubuntu13_source.buildinfo: done.
  Uploading landscape-client_19.12-0ubuntu13_source.changes: done.
Successfully uploaded packages.

diff --git a/debian/changelog b/debian/changelog
index 2217fe8..fcf9dca 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,15 @@
+landscape-client (19.12-0ubuntu13) jammy; urgency=medium
+
+  * d/landscape-sysinfo.wrapper, d/landscape-common.postrm: avoid too
+    frequent expensive operations (LP: #1893716)
+    - use a cache file and refresh it only once per minute
+    - use a single printf to format output
+    - if the former info was useful and we'd replace it with "sorry, load to
+      high" skip that update
+    - remove the cache file on purge
+
+ -- Christian Ehrhardt <[e-mail]>  Wed, 30 Mar 2022 12:32:38 +0200
+
 landscape-client (19.12-0ubuntu12) jammy; urgency=medium
 
   * d/p/lp1903776-release-upgrade.patch (LP: #1903776)
diff --git a/debian/landscape-common.postrm b/debian/landscape-common.postrm
index bad36ca..6b5f8ab 100644
--- a/debian/landscape-common.postrm
+++ b/debian/landscape-common.postrm
@@ -41,6 +41,12 @@ case "$1" in
 
         LOG_DIR=/var/log/landscape
         rm -f "${LOG_DIR}/sysinfo.log"*
+
+        #########################################
+        # from landscape-common
+
+        CACHE_FILE="/var/lib/landscape/landscape-sysinfo.cache"
+        rm -f "${CACHE_FILE}"
     ;;
 
     remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
diff --git a/debian/landscape-sysinfo.wrapper b/debian/landscape-sysinfo.wrapper
index e0ae2f3..54f139d 100644
--- a/debian/landscape-sysinfo.wrapper
+++ b/debian/landscape-sysinfo.wrapper
@@ -1,17 +1,29 @@
 #!/bin/sh
-# pam_motd does not carry the environment
-[ -f /etc/default/locale ] && . /etc/default/locale
-export LANG
-cores=$(grep -c ^processor /proc/cpuinfo 2>/dev/null)
-[ "$cores" -eq "0" ] && cores=1
-threshold="${cores:-1}.0"
-if [ $(echo "`cut -f1 -d ' ' /proc/loadavg` < $threshold" | bc) -eq 1 ]; then
-    echo
-    echo -n "  System information as of "
-    /bin/date
-    echo
-    /usr/bin/landscape-sysinfo
-else
-    echo
-    echo " System information disabled due to load higher than $threshold"
+
+# don't try refresh this more than once per minute
+# Due to cpu consumption and login delays (LP: #1893716)
+stamp="/var/lib/landscape/landscape-sysinfo.cache"
+NEED_UPDATE="FALSE"
+[ -z "$(find "$stamp" -newermt 'now-1 minutes' 2> /dev/null)" ] && NEED_UPDATE="TRUE"
+
+if [ "$NEED_UPDATE" = "TRUE" ]; then
+    # pam_motd does not carry the environment
+    [ -f /etc/default/locale ] && . /etc/default/locale
+    export LANG
+    cores=$(grep -c ^processor /proc/cpuinfo 2>/dev/null)
+    [ "$cores" -eq "0" ] && cores=1
+    threshold="${cores:-1}.0"
+    if [ $(echo "`cut -f1 -d ' ' /proc/loadavg` < $threshold" | bc) -eq 1 ]; then
+        printf "\n  System information as of %s\n\n%s\n" \
+            "$(/bin/date)" \
+            "$(/usr/bin/landscape-sysinfo)" \
+            > "$stamp"
+    else
+        # do not replace a formerly good result due to load
+        if ! grep -q "System information as of" $stamp 2> /dev/null; then
+            printf "\n System information disabled due to load higher than %s\n" "$threshold" > "$stamp"
+        fi
+    fi
 fi
+
+[ ! -r "$stamp" ] || cat "$stamp"