rpm: improve process timing for safety

Points

* FROM-package just leaves tmp files if it supports the features.
* TO-package trigger the features if there are those tmp files.
* Thus, can ensure that both FROM and TO support the feature.
* Make installing plugin and restarting the same condition.

Before

1. to-pre(2): Collect plugin-list.
2. Install TO-package
3. to-post(2): Install plugin.
4. from-preun(1): Do nothing.
5. Uninstall FROM-package
6. from-postun(1): Install plugin and restart if need.

After

1. to-pre(2): Do nothing.
2. Install TO-package
3. to-post(2): Do nothing.
4. from-preun(1):
   * Check auto or not.
   * Leave plugin-list and pid if need.
5. Uninstall FROM-package
6. from-postun(1): Disable `%systemd_postun_with_restart`.
7. to-posttrans: Install plugin and restart if need.

Signed-off-by: Daijiro Fukuda <[email protected]>

fluent-package/yum/fluent-package.spec.in

@@ -33,6 +33,7 @@
 %define v4migration_old_rotate_config_saved /tmp/@PACKAGE_DIR@/.old_rotate_config
 %define v4migration_enabled_service /tmp/@PACKAGE_DIR@/.v4migration_enabled_service
 %define local_base_plugins /tmp/@PACKAGE_DIR@/.local_base_plugins
+%define pid_for_auto_restart /tmp/@PACKAGE_DIR@/.pid_for_auto_restart
 
 # Omit the brp-python-bytecompile automagic because post hook for ffi fails on AmazonLinux 2.
 %if %{_amazon_ver} == 2
@@ -187,17 +188,24 @@ else
         /usr/sbin/useradd --system --uid $TD_UID --gid $TD_GID --home-dir %{_localstatedir}/lib/@PACKAGE_DIR@ --shell /sbin/nologin --non-unique @SERVICE_NAME@
     fi
 fi
-if [ $1 -eq 2 ]; then
-  . %{_sysconfdir}/sysconfig/@SERVICE_NAME@
-  echo "pre FLUENT_PACKAGE_SERVICE_RESTART: $FLUENT_PACKAGE_SERVICE_RESTART"
-  if [ "$FLUENT_PACKAGE_SERVICE_RESTART" = auto ]; then
-    # collect installed gems during upgrading
-    /usr/sbin/fluent-gem list '^fluent-plugin-' --no-versions --no-verbose > %{local_base_plugins}
-  fi
-fi
 
 %preun
 %systemd_preun @[email protected]
+if [ $1 -eq 1 ]; then
+  # systemctl ... --property=MainPID --value is available since systemd 230 or later.
+  # thus for amazonlinux:2, it can not be used.
+  pid="$(systemctl show "@SERVICE_NAME@" --property=MainPID | cut -d'=' -f2)"
+  if [ "$pid" -eq 0 ]; then
+    echo "Do not use auto restart because the service is not active"
+  else
+    . %{_sysconfdir}/sysconfig/@SERVICE_NAME@
+    echo "FLUENT_PACKAGE_SERVICE_RESTART: $FLUENT_PACKAGE_SERVICE_RESTART"
+    if [ "$FLUENT_PACKAGE_SERVICE_RESTART" = auto ]; then
+      /usr/sbin/fluent-gem list '^fluent-plugin-' --no-versions --no-verbose > %{local_base_plugins}
+      echo "$pid" > %{pid_for_auto_restart}
+    fi
+  fi
+fi
 
 %post
 %systemd_post @[email protected]
@@ -291,51 +299,9 @@ if [ -f "%{_sysconfdir}/prelink.conf" ]; then
     %{__sed} -i"" %{_sysconfdir}/prelink.conf -e "/\/opt\/td-agent\/bin\/ruby/d"
   fi
 fi
-if [ $1 -eq 2 ]; then
-  # install missing plugins during upgrading package
-  if [ -f %{local_base_plugins} ]; then
-    local_current_plugins=$(/usr/sbin/fluent-gem list '^fluent-plugin-' --no-versions --no-verbose)
-    if ! grep --fixed-strings --line-regexp --invert-match "$local_current_plugins" %{local_base_plugins}; then
-      echo "No missing plugins to install"
-    else
-      if ! curl --fail --silent -O https://rubygems.org/specs.4.8.gz; then
-        echo "No network connectivity..."
-      else
-        grep --fixed-strings --line-regexp --invert-match "$local_current_plugins" %{local_base_plugins} | while read missing_gem
-        do
-          if ! /usr/sbin/fluent-gem install --no-document $missing_gem; then
-            echo "Can't install missing plugin automatically: please install $missing_gem manually."
-          fi
-        done
-      fi
-    fi
-    rm -f %{local_base_plugins}
-  fi
-fi
 
 %postun
-if [ $1 -eq 1 ]; then
-  # Control service during upgrading
-  . %{_sysconfdir}/sysconfig/@SERVICE_NAME@
-  echo "postun FLUENT_PACKAGE_SERVICE_RESTART: $FLUENT_PACKAGE_SERVICE_RESTART"
-  if [ "$FLUENT_PACKAGE_SERVICE_RESTART" = "auto" ]; then
-    # systemctl ... --property=MainPID --value is available since systemd 230 or later.
-    # thus for amazonlinux:2, it can not be used.
-    pid=$(systemctl show fluentd --property=MainPID | cut -d'=' -f2)
-    if [ $pid -gt 0 ]; then
-      echo "Kick auto service upgrade mode to MainPID:$pid"
-      kill -USR2 $pid
-    else
-      # no running fluentd service
-      echo "Suppress auto service upgrade mode to MainPID:$pid"
-    fi
-  elif [ "$FLUENT_PACKAGE_SERVICE_RESTART" = "manual" ]; then
-    echo "No need to restart service in manual mode..."
-  else
-    # no support for upgrading without downtime
-    %systemd_postun_with_restart @[email protected]
-  fi
-fi
+# Disable systemd_postun_with_restart to manage restart on the package side.
 if [ $1 -eq 0 ]; then
   # Uninstall
   # Without this uninstall conditional guard block ($1 -eq 0), symlink
@@ -400,6 +366,30 @@ if [ -f %{v4migration} ]; then
     rm -f %{v4migration_with_restart}
   fi
 fi
+if [ -f %{local_base_plugins} ]; then
+  local_current_plugins=$(/usr/sbin/fluent-gem list '^fluent-plugin-' --no-versions --no-verbose)
+  if ! grep --fixed-strings --line-regexp --invert-match "$local_current_plugins" %{local_base_plugins}; then
+    echo "No missing plugins to install"
+  else
+    if ! curl --fail --silent -O https://rubygems.org/specs.4.8.gz; then
+      echo "No network connectivity..."
+    else
+      grep --fixed-strings --line-regexp --invert-match "$local_current_plugins" %{local_base_plugins} | while read missing_gem
+      do
+        if ! /usr/sbin/fluent-gem install --no-document $missing_gem; then
+          echo "Can't install missing plugin automatically: please install $missing_gem manually."
+        fi
+      done
+    fi
+  fi
+  rm -f %{local_base_plugins}
+fi
+if [ -f %{pid_for_auto_restart} ]; then
+  pid=$(cat %{pid_for_auto_restart})
+  echo "Kick auto restart to MainPID:$pid"
+  kill -USR2 $pid
+  rm -f %{pid_for_auto_restart}
+fi
 
 %files
 %doc README.md