PT-2289 - Allow pt-stalk do disable ps-lock-transactions data collection via parameter

- Implemented _should_skip function as was suggested

bin/pt-stalk

@@ -971,7 +971,7 @@ collect_mysql_data_one() {
       fi
    fi
 
-   if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "mysqladmin" ]]; then
+   if ! _should_skip "mysqladmin"; then
       $CMD_MYSQLADMIN $EXT_ARGV ext -i$OPT_SLEEP_COLLECT -c$cnt >>"$d/$p-mysqladmin" &
       mysqladmin_pid=$!
    fi
@@ -1016,7 +1016,7 @@ collect_system_data() {
 
 collect_mysql_data_loop() {
 
-   if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "processlist" ]]; then
+   if ! _should_skip "processlist"; then
       (echo $ts; $CMD_MYSQL $EXT_ARGV -e "SHOW FULL PROCESSLIST\G") \
       >> "$d/$p-processlist" &
    fi
@@ -1025,16 +1025,16 @@ collect_mysql_data_loop() {
    >> "$d/$p-threads" &
 
    if [ "$have_lock_waits_table" ]; then
-      if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "lock-waits" ]]; then
+      if ! _should_skip "lock-waits"; then
          (echo $ts; lock_waits "$d/lock_waits.running")   >>"$d/$p-lock-waits" &
       fi
-      if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "transactions" ]]; then
+      if ! _should_skip "transactions"; then
          (echo $ts; transactions) >>"$d/$p-transactions" &
       fi
    fi
 
    if [ "${mysql_version}" '>' "5.6" ] && [ $ps_instrumentation_enabled == "yes" ] \
-      && ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "ps-locks-transactions" ]]; then
+      && ! _should_skip "ps-locks-transactions"; then
       ps_locks_transactions "$d/$p-ps-locks-transactions"
    fi
 
@@ -1261,7 +1261,7 @@ innodb_status() {
 
    local innostat=""
 
-   if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "innodbstatus" ]]; then
+   if ! _should_skip "innodbstatus"; then
       $CMD_MYSQL $EXT_ARGV -e "SHOW /*!40100 ENGINE*/ INNODB STATUS\G" \
          >> "$d/$p-innodbstatus$n"
       grep "END OF INNODB" "$d/$p-innodbstatus$n" >/dev/null || {
@@ -1285,7 +1285,7 @@ rocksdb_status() {
     has_rocksdb=`$CMD_MYSQL $EXT_ARGV -e "SHOW ENGINES" | grep -i 'rocksdb'`
     exit_code=$?
 
-    if [ $exit_code -eq 0 ] && ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "rocksdbstatus" ]]; then
+    if [ $exit_code -eq 0 ] && ! _should_skip "rocksdbstatus"; then
         $CMD_MYSQL $EXT_ARGV -e "SHOW ENGINE ROCKSDB STATUS\G" \
                    >> "$d/$p-rocksdbstatus$n" || rm -f "$d/$p-rocksdbstatus$n"
     fi
@@ -1367,7 +1367,7 @@ collect_mysql_variables() {
    echo -e "\n$sql\n" >> $outfile
    $CMD_MYSQL $EXT_ARGV -e "$sql" >> $outfile
 
-   if ! [[ "${OPT_SKIP_COLLECTION[@]}" =~ "thread-variables" ]]; then
+   if ! _should_skip "thread-variables"; then
       sql="select * from performance_schema.variables_by_thread order by thread_id, variable_name;"
       echo -e "\n$sql\n" >> $outfile
       $CMD_MYSQL $EXT_ARGV -e "$sql" >> $outfile
@@ -1383,6 +1383,19 @@ collect_mysql_variables() {
 
 }
 
+_should_skip() {
+   local name=$1
+
+   for item in "${OPT_SKIP_COLLECTION[@]}"; do
+   echo $item >> /tmp/sveta
+      if [ "$item" == "$name" ]; then
+         return 0
+      fi
+   done
+
+   return 1
+}
+
 # ###########################################################################
 # End collect package
 # ###########################################################################
@@ -1740,19 +1753,6 @@ main() {
       log 'Both options --system-only and --mysql-only specified, collecting only disk-space, hostname, output, and trigger metrics';
    fi
 
-   if [ "$OPT_SKIP_COLLECTION" ]; then
-      local supported_skips=(ps-locks-transactions thread-variables innodbstatus lock-waits mysqladmin processlist rocksdbstatus transactions)
-      IFS=',' read -ra skips <<< "$OPT_SKIP_COLLECTION"
-      OPT_SKIP_COLLECTION=("${skips[*]}")
-      for skip in "${skips[@]}"; do
-         echo "$supported_skips" | grep -q "$skip"
-         if ! [[ " ${supported_skips[@]} " =~ " ${skip} " ]]; then
-            log "Invalid --skip-collection value: $skip, exiting."
-            exit 1
-         fi
-      done
-   fi
-
    # Note: $$ is the parent's PID, but we're a child proc.
    # Bash 4 has $BASHPID but we can't rely on that.  Consequently,
    # we don't know our own PID.  See the usage of $! below.
@@ -1810,6 +1810,19 @@ if    [ "${0##*/}" = "$TOOL" ] \
       fi
    fi
 
+   if [ "$OPT_SKIP_COLLECTION" ]; then
+      local supported_skips=(ps-locks-transactions thread-variables innodbstatus lock-waits mysqladmin processlist rocksdbstatus transactions)
+      IFS=',' read -ra skips <<< "$OPT_SKIP_COLLECTION"
+      OPT_SKIP_COLLECTION=("${skips[@]}")
+      for skip in "${skips[@]}"; do
+         echo "$supported_skips" | grep -q "$skip"
+         if ! [[ " ${supported_skips[@]} " =~ " ${skip} " ]]; then
+            log "Invalid --skip-collection value: $skip, exiting."
+            exit 1
+         fi
+      done
+   fi
+
    if [ -z "$OPT_STALK" -a "$OPT_COLLECT" ]; then
       # Not stalking; do immediate collect once.
       OPT_CYCLES=0