Do not log an error during resource deletion

A notify script is being called by the galera library each time it
transitions into another state (e.g. Connected -> Synced).
The notify script uses a token generated by k8s to communicate with
the API server and update the current endpoint for the galera service.

When a galera resource is deleted, the token becomes invalid, so
when the notify script is called, it cannot connect to the API server
anymore. This is not needed as the resource is being deleted anyway,
so handle that case to avoid logging unecessary errors.

Author: dciabrin

templates/galera/bin/mysql_wsrep_notify.sh

@@ -15,11 +15,14 @@ CACERT=${SERVICEACCOUNT}/ca.crt
 RETRIES=6
 WAIT=1
 
+
 ##
 ## Utilities functions
 ##
+## NOTE: mysql diverts this script's stdout, but stderr is logged to the
+## configured log-error file (e.g. /var/log/mariadb/mariadb.log)
 function log() {
-    echo "$(date +%F_%H_%M_%S) `basename $0` $*"
+    echo "$(date +%F_%H_%M_%S) `basename $0` $*" >&2
 }
 
 function log_error() {
@@ -65,6 +68,11 @@ function api_server {
     if echo "${output}" | grep -q '"status": "Failure"'; then
         message=$(echo "${output}" | parse_output '["message"]')
         code=$(echo "${output}" | parse_output '["code"]')
+        if [ "${code}" = 401 ]; then
+            # Unauthorized means the token is no longer valid as the galera
+            # resource is in the process of being deleted.
+            return 2
+        fi
         log_error "API server returned an error for service ${SERVICE}: ${message} (code=${code})"
         return 1
     fi
@@ -98,9 +106,16 @@ function retry {
     local retries=$RETRIES
     local wait=$WAIT
     local rc=1
+
     $action
     rc=$?
     while [ $rc -ne 0 -a $retries -gt 0 ]; do
+        # if API call are unauthorized, the resource is being deleted
+        # exit now as there is nothing more to do
+        if [ $rc -eq 2 ]; then
+            log "galera resource is being deleted, exit now."
+            return 0
+        fi
         log_error "previous action failed, retrying."
         sleep $wait
         $action
@@ -129,7 +144,8 @@ function reconfigure_service_endpoint {
     fi
 
     CURRENT_SVC=$(api_server GET "$SERVICE")
-    [ $? == 0 ] || return 1
+    local rc=$?
+    [ $rc == 0 ] || return $rc
 
     CURRENT_ENDPOINT=$(echo "$CURRENT_SVC" | parse_output '["spec"]["selector"].get("statefulset.kubernetes.io/pod-name","")')
     [ $? == 0 ] || return 1
@@ -151,7 +167,8 @@ function reconfigure_service_endpoint {
 ## Change the Active endpoint from the service
 function remove_service_endpoint {
     CURRENT_SVC=$(api_server GET "$SERVICE")
-    [ $? == 0 ] || return 1
+    local rc=$?
+    [ $rc == 0 ] || return $rc
 
     CURRENT_ENDPOINT=$(echo "$CURRENT_SVC" | parse_output '["spec"]["selector"].get("statefulset.kubernetes.io/pod-name","")')
     [ $? == 0 ] || return 1
@@ -174,9 +191,6 @@ function remove_service_endpoint {
 
 ## Main
 
-# mysql diverts this script's stdout/stderr, so in order for its output
-# to be logged properly, reuse dumb-init's stdout
-exec &> >(tee -a /proc/1/fd/1) 2>&1
 log "called with args: $*"
 
 # Galera always calls script with --status argument