Fix debian packaging for upgrades

changelog/fragments/1722954476-Fix-loss-of-state.enc-on-upgrade-with-debian-packaging.yaml

@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: bug-fix
+
+# Change summary; a 80ish characters long description of the change.
+summary: Fix loss of state.enc on upgrade with debian packaging
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+#description:
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component:
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/5260
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+issue: https://github.com/elastic/elastic-agent/issues/5101

dev-tools/packaging/packages.yml

@@ -20,6 +20,7 @@ shared:
   # Deb/RPM spec for community beats.
   - &deb_rpm_agent_spec
     <<: *common
+    pre_install_script: '{{ elastic_beats_dir }}/dev-tools/packaging/templates/linux/preinstall.sh.tmpl'
     post_install_script: '{{ elastic_beats_dir }}/dev-tools/packaging/templates/linux/postinstall.sh.tmpl'
     post_rm_script: '{{ elastic_beats_dir }}/dev-tools/packaging/templates/linux/postrm.sh.tmpl'
     files:

dev-tools/packaging/templates/linux/postinstall.sh.tmpl

@@ -2,42 +2,12 @@
 
 set -e
 
-symlink="/usr/share/elastic-agent/bin/elastic-agent"
-old_agent_dir=""
-
-# check if $symlink exists for the previous install
-# and derive the old agent directory
-if test -L "$symlink"; then
-    resolved_symlink="$(readlink -f -- "$symlink")"
-    # check if it is resolved to non empty string
-    if ! [ -z "$resolved_symlink" ]; then
-        old_agent_dir="$( dirname "$resolved_symlink" )"
-    fi
-fi
-
 commit_hash="{{ commit_short }}"
 version_dir="{{agent_package_version}}{{snapshot_suffix}}"
-
+symlink="/usr/share/elastic-agent/bin/elastic-agent"
 new_agent_dir="/var/lib/elastic-agent/data/elastic-agent-$version_dir-$commit_hash"
 
-# copy the state files if there was a previous agent install
-if ! [ -z "$old_agent_dir" ] && ! [ "$old_agent_dir" -ef "$new_agent_dir" ]; then
-    yml_path="$old_agent_dir/state.yml"
-    enc_path="$old_agent_dir/state.enc"
-    echo "migrate state from $old_agent_dir to $new_agent_dir"
-
-    if test -f "$yml_path"; then
-        echo "found "$yml_path", copy to "$new_agent_dir"."
-        cp "$yml_path" "$new_agent_dir"
-    fi
-
-    if test -f "$enc_path"; then
-        echo "found "$enc_path", copy to "$new_agent_dir"."
-        cp "$enc_path" "$new_agent_dir"
-    fi
-fi
-
-# delete symlink if exists
+# delete $symlink if exists
 if test -L "$symlink"; then
     echo "found symlink $symlink, unlink"
     unlink "$symlink"
@@ -47,5 +17,9 @@ fi
 echo "create symlink "$symlink" to "$new_agent_dir/elastic-agent""
 ln -s "$new_agent_dir/elastic-agent" "$symlink"
 
+# reload systemctl and then restart service
+echo "systemd enable/restart elastic-agent"
 systemctl daemon-reload 2> /dev/null
+systemctl enable elatic-agent 2> /dev/null || true
+systemctl restart elastic-agent 2> /dev/null || true
 exit 0

dev-tools/packaging/templates/linux/preinstall.sh.tmpl

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+set -e
+
+commit_hash="{{ commit_short }}"
+version_dir="{{agent_package_version}}{{snapshot_suffix}}"
+symlink="/usr/share/elastic-agent/bin/elastic-agent"
+new_agent_dir="/var/lib/elastic-agent/data/elastic-agent-$version_dir-$commit_hash"
+old_agent_dir=""
+
+# upon upgrade we migrate the current symlink to an upgrade symlink as the previous
+# installed version will remove the symlink
+if test -L "$symlink"; then
+    resolved_symlink="$(readlink -- "$symlink")"
+    if ! [ -z "$resolved_symlink" ]; then
+        old_agent_dir="$( dirname "$resolved_symlink" )"
+        echo "previous installation directory $old_agent_dir"
+    else
+        echo "unable to read existing symlink"
+    fi
+
+    # copy the state files if there was a previous agent install
+    if ! [ -z "$old_agent_dir" ] && ! [ "$old_agent_dir" -ef "$new_agent_dir" ]; then
+        yml_path="$old_agent_dir/state.yml"
+        enc_path="$old_agent_dir/state.enc"
+        echo "migrate state from $old_agent_dir to $new_agent_dir"
+
+        if test -f "$yml_path"; then
+            echo "found "$yml_path", copy to "$new_agent_dir"."
+            mkdir -p "$new_agent_dir"
+            cp "$yml_path" "$new_agent_dir"
+        else
+            echo "didn't find $yml_path"
+        fi
+
+        if test -f "$enc_path"; then
+            echo "found "$enc_path", copy to "$new_agent_dir"."
+            mkdir -p "$new_agent_dir"
+            cp "$enc_path" "$new_agent_dir"
+        else
+            echo "didn't find $enc_path"
+        fi
+    fi
+else
+    echo "no previous installation found"
+fi