Bug#26643372 DOCKER IMAGE LOGS TO A FILE INSIDE THE CONTAINER WHICH I…

…S DIFFICULT TO REACH

Add an environment variable MYSQL_LOG_STDOUT which, when set (any non-empty value), makes
the entrypoint script comment out the log-error line from the default config file.
This will make the command "docker logs container" output the MySQL server log

The flag has no effect on 8.0, where this is the default behavior

changelog

@@ -2,6 +2,10 @@ Changes in 1.1.1 (not released)
  * Disable binlog for all entrypoint client commands (#87305)
    This was previously only done only for the script to set the root password,
    but should be done for all client commands, or group replication will fail
+ * Add flag for logging to stdout (#87458)
+   Setting -e MYSQL_LOG_STDOUT=true will make the server log to stdout, so the
+   server log is available through Docker's log interface.
+
 Changes in 1.1.0 (2017-07-24)
  * Fixed broken MYSQL_ONETIME_PASSWORD support (#86523)
    The functionality wasn't correctly updated when the entrypoint script was

genOracleLinux.sh

@@ -87,6 +87,13 @@ TZINFO_WORKAROUND["5.6"]="sed 's/Local time zone must be set--see zic manual pag
 TZINFO_WORKAROUND["5.7"]=""
 TZINFO_WORKAROUND["8.0"]=""
 
+# Logging to stdout makes server log available with the «docker logs command»
+declare -A DEFAULT_LOG
+DEFAULT_LOG["5.5"]=""
+DEFAULT_LOG["5.6"]=""
+DEFAULT_LOG["5.7"]=""
+DEFAULT_LOG["8.0"]="stdout"
+
 for VERSION in ${VERSIONS}
 do
   # Dockerfile
@@ -103,6 +110,7 @@ do
   sed -i 's#%%INIT_STARTUP%%#'"${INIT_STARTUP[${VERSION}]}"'#g' tmpfile
   sed -i 's#%%STARTUP_WAIT%%#'"${STARTUP_WAIT[${VERSION}]}"'#g' tmpfile
   sed -i 's#%%SERVER_VERSION_FULL%%#'"${SERVER_VERSION_FULL[${VERSION}]}"'#g' tmpfile
+  sed -i 's#%%DEFAULT_LOG%%#'"${DEFAULT_LOG[${VERSION}]}"'#g' tmpfile
   mv tmpfile ${VERSION}/docker-entrypoint.sh
   chmod +x ${VERSION}/docker-entrypoint.sh
 

template/docker-entrypoint.sh

@@ -46,6 +46,10 @@ if [ "$1" = 'mysqld' ]; then
 	DATADIR="$(_get_config 'datadir' "$@")"
 	SOCKET="$(_get_config 'socket' "$@")"
 
+	if [ -n "$MYSQL_LOG_STDOUT" ] || [ -n "%%DEFAULT_LOG%%" ]; then
+		sed -i 's/^log-error=/#&/' /etc/my.cnf
+	fi
+
 	if [ ! -d "$DATADIR/mysql" ]; then
 		if [ -z "$MYSQL_ROOT_PASSWORD" -a -z "$MYSQL_ALLOW_EMPTY_PASSWORD" -a -z "$MYSQL_RANDOM_ROOT_PASSWORD" ]; then
 			echo >&2 '[Entrypoint] ERROR: No password option specified for new database.'