Add and test --config to pt-stalk.

bin/pt-stalk

@@ -54,12 +54,12 @@ die() {
 
 set -u
 
-ARGV=""              # Non-option args (probably input files)
-EXT_ARGV=""          # Everything after -- (args for an external command)
-HAVE_EXT_ARGV=""     # Got --, everything else is put into EXT_ARGV
-OPT_ERRS=0           # How many command line option errors
-OPT_VERSION="no"     # If --version was specified
-OPT_HELP="no"        # If --help was specified
+ARGV=""           # Non-option args (probably input files)
+EXT_ARGV=""       # Everything after -- (args for an external command)
+HAVE_EXT_ARGV=""  # Got --, everything else is put into EXT_ARGV
+OPT_ERRS=0        # How many command line option errors
+OPT_VERSION=""    # If --version was specified
+OPT_HELP=""       # If --help was specified
 PO_DIR="$TMPDIR/po"  # Directory with program option spec files
 
 usage() {
@@ -74,13 +74,13 @@ usage() {
 usage_or_errors() {
    local file="$1"
 
-   if [ "$OPT_VERSION" = "yes" ]; then
+   if [ "$OPT_VERSION" ]; then
       local version=$(grep '^pt-[^ ]\+ [0-9]' "$file")
       echo "$version"
       return 1
    fi
 
-   if [ "$OPT_HELP" = "yes" ]; then
+   if [ "$OPT_HELP" ]; then
       usage "$file"
       echo
       echo "Command line options:"
@@ -111,8 +111,8 @@ parse_options() {
    EXT_ARGV=""
    HAVE_EXT_ARGV=""
    OPT_ERRS=0
-   OPT_VERSION="no"
-   OPT_HELP="no"
+   OPT_VERSION=""
+   OPT_HELP=""
    PO_DIR="$TMPDIR/po"
 
    if [ ! -d "$PO_DIR" ]; then
@@ -129,9 +129,23 @@ parse_options() {
       exit 1
    fi
 
-   _parse_pod "$file"
-   _eval_po
-   _parse_config_files
+   _parse_pod "$file"  # Parse POD into program option (po) spec files
+   _eval_po            # Eval po into existence with default values
+
+   if [ $# -ge 2 ] &&  [ "$1" = "--config" ]; then
+      shift  # --config
+      local user_config_files="$1"
+      shift  # that ^
+      local old_ifs="$IFS"
+      IFS=","
+      for user_config_file in $user_config_files; do
+         _parse_config_files "$user_config_file"
+      done
+      IFS="$old_ifs"
+   else
+      _parse_config_files "/etc/percona-toolkit/percona-toolkit.conf" "/etc/percona-toolkit/$TOOL.conf" "$HOME/.percona-toolkit.conf" "$HOME/.$TOOL.conf"
+   fi
+
    _parse_command_line "$@"
 }
 
@@ -218,8 +232,8 @@ _eval_po() {
 }
 
 _parse_config_files() {
-   for config_file in "/etc/percona-toolkit/percona-toolkit.conf" "/etc/percona-toolkit/$TOOL.conf" "$HOME/.percona-toolkit.conf" "$HOME/.$TOOL.conf"
-   do
+
+   for config_file in "$@"; do
       test -f "$config_file" || continue
 
       while read config_opt; do
@@ -228,12 +242,16 @@ _parse_config_files() {
 
          config_opt="$(echo "$config_opt" | sed -e 's/^[ ]*//' -e 's/[ ]*\$//' -e 's/[ ]*=[ ]*/=/' -e 's/[ ]*#.*$//')"
 
+         [ "$config_opt" = "" ] && continue
+
          if ! [ "$HAVE_EXT_ARGV" ]; then
             config_opt="--$config_opt"
          fi
+
          _parse_command_line "$config_opt"
+
       done < "$config_file"
-      
+
       HAVE_EXT_ARGV=""  # reset for each file
 
    done
@@ -1212,6 +1230,13 @@ Collect strace data.
 
 Collect tcpdump data.
 
+=item --config
+
+type: string
+
+Read this comma-separated list of config files.  If specified, this must be the
+first option on the command line.
+
 =item --cycles
 
 type: int; default: 5