err

   1 #!/bin/bash
   2 # Copyright 2018 Ian Kelling
   3
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7
   8 # http://www.apache.org/licenses/LICENSE-2.0
   9
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16
  17 # Commentary: Bash stack trace and error handling functions. This file
  18 # is meant to be sourced. It loads some functions which you may want to
  19 # call manually (see the comments at the start of each one), and then
  20 # runs err-catch. See the README file for a slightly longer explanation.
  21
  22 err-allow() {
  23   # help: turn off exit and stack trace on error. undoes err-catch
  24   set +E +o pipefail; trap ERR
  25 }
  26
  27 err-bash-trace() {
  28   # help: print stack trace
  29   #
  30   # Note: It does not show function args unless you first run:
  31   # shopt -s extdebug
  32   # err-catch runs this for you.
  33
  34   local -i argc_index=0 frame i start=${1:-1} max_indent=8 indent
  35   local source
  36   local extdebug=false
  37   if [[ $(shopt -p extdebug) == *-s* ]]; then
  38     extdebug=true
  39   fi
  40   for ((frame=0; frame < ${#FUNCNAME[@]}-1; frame++)); do
  41     argc=${BASH_ARGC[frame]}
  42     argc_index+=$argc
  43     ((frame < start)) && continue
  44     if (( ${#BASH_SOURCE[@]} > 1 )); then
  45       source="${BASH_SOURCE[frame+1]}:${BASH_LINENO[frame]}:"
  46     fi
  47     indent=$((frame-start+1))
  48     indent=$((indent < max_indent ? indent : max_indent))
  49     printf "%${indent}s↳%sin \`%s" '' "$source" "${FUNCNAME[frame]}"
  50     if $extdebug; then
  51       for ((i=argc_index-1; i >= argc_index-argc; i--)); do
  52         printf " %s" "${BASH_ARGV[i]}"
  53       done
  54     fi
  55     echo \'
  56   done
  57 }
  58
  59 err-catch() {
  60   # help: on errors: print stack trace and exit
  61   #
  62   # You can set "${_errcatch_cleanup[@]}" to a command and it will run before exiting.
  63   # This function depends on err-bash-trace.
  64
  65   set -E; shopt -s extdebug
  66   _err-trap() {
  67     err=$?
  68     exec >&2
  69     set +x
  70     echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}:in \`$BASH_COMMAND' returned $err"
  71     # err trap does not work within an error trap, the following line:
  72     err-bash-trace 2; set -e
  73     "${_errcatch_cleanup[@]:-:}" # note :-: is to be compatible with set -u
  74     echo "$0: exiting with code $err"
  75     exit $err
  76   }
  77   trap _err-trap ERR
  78   set -o pipefail
  79 }
  80
  81 err-exit() {
  82   # usage: err-exit [EXIT_CODE] [MESSAGE]
  83   # help: exit and print stack trace.
  84   #
  85   # Use this instead of the exit command to be more informative. default
  86   # EXIT_CODE is 1. If only one of EXIT_CODE and MESSAGE is given,
  87   # we consider it to be an exit code if it is a number.
  88   # This function depends on err-bash-trace.
  89
  90   exec >&2
  91   code=1
  92   if [[ "$*" ]]; then
  93     if [[ ${1/[^0-9]/} == "$1" ]]; then
  94       code=$1
  95       if [[ $2 ]]; then
  96         printf '%s\n' "$2"
  97       fi
  98     else
  99       printf '%s\n' "$0: $1"
 100     fi
 101   fi
 102   echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}"
 103   err-bash-trace 2
 104   echo "$0: exiting with code $code"
 105   exit $err
 106 }
 107
 108 err-catch