Clean up pt-sift: capture signals, verify and simplify arg processing, improve error messages and docs, exit if there are no pt-stalk files.

bin/pt-sift

@@ -1,14 +1,12 @@
 #!/usr/bin/env bash
 
-TOOL="pt-sift"
-
 # This program is part of Percona Toolkit: http://www.percona.com/software/
 # See "COPYRIGHT, LICENSE, AND WARRANTY" at the end of this file for legal
 # notices and disclaimers.
 
 usage() {
    if [ "${OPT_ERR}" ]; then
-      echo "${OPT_ERR}" >&2
+      echo "Error: $OPT_ERR" >&2
    fi
    echo "Usage: pt-sift FILE|PREFIX|DIRECTORY" >&2
    echo "For more information, 'man pt-sift' or 'perldoc $0'." >&2
@@ -56,6 +54,24 @@ rm_tmpdir() {
 # End tmpdir package
 # ###########################################################################
 
+# ###########################################################################
+# Global variables
+# ###########################################################################
+
+TOOL="pt-sift"
+BASEDIR="$PWD"
+PREFIX=""
+
+# ###########################################################################
+# Subroutines
+# ###########################################################################
+
+sigtrap() {
+   echo "Caught signal, exiting" >&2
+   rm_tmpdir
+   exit 0
+}
+
 # Show current help and settings
 print_help() {
    cat <<-HELP
@@ -75,23 +91,34 @@ print_help() {
 	HELP
 }
 
-# The main code that runs by default.  Arguments are the command-line options.
+# ###########################################################################
+# Main program loop, called below if tool is ran from the command line.
+# ###########################################################################
+
 main() {
+   trap sigtrap SIGHUP SIGINT SIGTERM
 
    # If there's a command-line arg, figure out if it's a file, directory, or
    # prefix.  The outcome of this block of code should be that BASEDIR is the
    # directory where the files live, without a trailing slash; and PREFIX is
    # either empty or a timestamp, such as "2011_02_08_16_58_07".
-   ARG="${1:-.}"
-   if [ -d "${ARG}" ]; then
-      BASEDIR="$(echo "${ARG}" | sed -e 's!/$!!')"
-      PREFIX=""
-   elif [ -f "${ARG}" -o -f "${ARG}-df" -o -f "${ARG}df" ]; then
-      BASEDIR="$(dirname "${ARG}")"
-      PREFIX="$(echo "${ARG}" | sed -e 's/-[a-z1]*$//' -e 's!^.*/!!')"
-   else
-      echo "Error: ${ARG} doesn't look like a directory, file, or file prefix"
-      exit 1
+   if [ $# -gt 1 ]; then
+      OPT_ERR="Specify only one PREFIX or DIR"
+      usage
+   fi
+
+   if [ $# -eq 1 ]; then
+      if [ -d "$1" ]; then
+         BASEDIR="$1"
+         PREFIX=""
+      elif [ -f "$1" -o -f "$1-df" -o -f "$1df" ]; then
+         BASEDIR="$(dirname "$1")"
+         PREFIX="$(echo "$1" | perl -ne '$_ =~ m/([\d_]+)/; print $1;')"
+      else
+         echo "Error: $1 is not a directory, and there are no pt-stalk files in the curent working directory ($BASEDIR) with a $1 prefix." >&2
+         echo "For more information, 'man pt-sift' or 'perldoc $0'." >&2
+         exit 1
+      fi
    fi
 
    # If the programs we need don't exist, try to get them.
@@ -121,7 +148,15 @@ main() {
 
    # We need to generate a list of timestamps, and ask the user to choose one if
    # there is no PREFIX yet.  NOTE: we rely on the "-df" files here.
-   ls "${BASEDIR}" | grep -- '-df$' | cut -d- -f1 | sort > $PT_TMPDIR/pt-sift.prefixes
+   (
+      cd "$BASEDIR"
+      ls *-df | cut -d- -f1 | sort > "$PT_TMPDIR/pt-sift.prefixes"
+   )
+   if [ ! -s "$PT_TMPDIR/pt-sift.prefixes" ]; then
+      echo "Error: There are no pt-stalk files in $BASEDIR" >&2
+      echo "For more information, 'man pt-sift' or 'perldoc $0'." >&2
+      exit 1
+   fi
    if [ -z "${PREFIX}" ]; then
       if [ "$(grep -c . $PT_TMPDIR/pt-sift.prefixes)" = "1" ]; then
          # If there is only one sample, we use it as the prefix.
@@ -134,7 +169,7 @@ main() {
       cat $PT_TMPDIR/pt-sift.prefixes | while read line; do
          i=$(($i + 1))
          echo -n "  $line"
-         if [ "${i}" = "3" ]; then
+         if [ $i -eq 3 ]; then
             echo
             i=0
          fi
@@ -552,15 +587,20 @@ fi
 
 =head1 NAME
 
-pt-sift - Browses files created by pt-collect.
+pt-sift - Browses files created by pt-stalk.
 
 =head1 SYNOPSIS
 
 Usage: pt-sift FILE|PREFIX|DIRECTORY
 
-pt-sift browses the files created by L<pt-collect>.  If you specify a
-FILE or PREFIX, it browses only files with that prefix.  If you specify a
-DIRECTORY, then it browses all files within that directory.
+pt-sift browses files created by L<pt-stalk>.  If no options are given,
+the tool browses all pt-stalk files in the current working directory.
+Specify a DIRECTORY to browse all files in that directory.  Specify
+a FILE to browse all files with the same prefix in that file's directory.
+Specify a PREFIX to browse all files in the current working directory
+with that prefix.  Prefixes are timestamps like C<2012_07_23_14_27_11>.
+The tool prompts for a prefix if more than is found, else the only available
+prefix is used by default.
 
 =head1 RISKS
 
@@ -585,7 +625,7 @@ See also L<"BUGS"> for more information on filing bugs and getting help.
 
 pt-sift downloads other tools that it might need, such as L<pt-diskstats>,
 and then makes a list of the unique timestamp prefixes of all the files in
-the directory, as written by the L<pt-collect> tool.  If the user specified
+the directory, as written by the L<pt-stalk> tool.  If the user specified
 a timestamp on the command line, then it begins with that sample of data;
 otherwise it begins by showing a list of the timestamps and prompting for
 a selection.  Thereafter, it displays a summary of the selected sample, and