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
  23 #######################################
  24 # Undoes err-catch. turns off exit and stack trace on error.
  25 #######################################
  26 err-allow() {
  27   set +E +o pipefail; trap ERR
  28 }
  29
  30
  31 #######################################
  32 # Print stack trace
  33 #
  34 # usage: err-bash-trace [FRAME_START]
  35 #
  36 # It does not show function args unless you first run:
  37 # shopt -s extdebug
  38 # which err-catch & err-print does for you.
  39 #
  40 # FRAME_START   The frame to start printing on. default=0. Useful when
  41 #               printing from an ERR trap function to avoid printing
  42 #               that function.
  43 #######################################
  44 err-bash-trace() {
  45   local -i argc_index=0 frame i start=${1:-0} max_indent=8 indent
  46   local source
  47   local extdebug=false
  48   if [[ $(shopt -p extdebug) == *-s* ]]; then
  49     extdebug=true
  50   fi
  51   for ((frame=0; frame < ${#FUNCNAME[@]}-1; frame++)); do
  52     argc=${BASH_ARGC[frame]}
  53     argc_index+=$argc
  54     ((frame <= start)) && continue
  55     if (( ${#BASH_SOURCE[@]} > 1 )); then
  56       source="${BASH_SOURCE[frame+1]}:${BASH_LINENO[frame]}:"
  57     fi
  58     indent=$((frame-start))
  59     indent=$((indent < max_indent ? indent : max_indent))
  60     printf "%${indent}s↳%sin \`%s" '' "$source" "${FUNCNAME[frame]}"
  61     if $extdebug; then
  62       for ((i=argc_index-1; i >= argc_index-argc; i--)); do
  63         printf " %s" "${BASH_ARGV[i]}"
  64       done
  65     fi
  66     echo \'
  67   done
  68   return 0
  69 }
  70
  71 #######################################
  72 # On error print stack trace and exit
  73 #
  74 # Globals:
  75 #   ${_errcatch_cleanup[@]}  Optional command & args that will run before exiting
  76 #######################################
  77 err-catch() {
  78   set -E; shopt -s extdebug
  79   _err-trap() {
  80     err=$?
  81     exec >&2
  82     set +x
  83     echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}: \`$BASH_COMMAND' returned $err"
  84     err-bash-trace 2
  85     set -e # err trap does not work within an error trap
  86     "${_errcatch_cleanup[@]:-:}" # note :-: is to be compatible with set -u
  87     echo "$0: exiting with code $err"
  88     exit $err
  89   }
  90   trap _err-trap ERR
  91   set -o pipefail
  92 }
  93
  94 #######################################
  95 # On error, print stack trace
  96 #######################################
  97 err-print() {
  98   # help: on errors: print stack trace
  99   #
 100   # This function depends on err-bash-trace.
 101
 102   set -E; shopt -s extdebug
 103   _err-trap() {
 104     err=$?
 105     exec >&2
 106     set +x
 107     echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}: \`$BASH_COMMAND' returned $err"
 108     err-bash-trace 2
 109   }
 110   trap _err-trap ERR
 111   set -o pipefail
 112 }
 113
 114
 115 #######################################
 116 # On error, print stack trace
 117 #
 118 # Use this instead of the exit command to be more informative.
 119 #
 120 # usage: err-exit [EXIT_CODE] [MESSAGE]
 121 #
 122 # EXIT_CODE  Default is 1.
 123 # MESSAGE    Print MESSAGE to stderr. If only one of EXIT_CODE
 124 #            and MESSAGE is given, we consider it to be an
 125 #            exit code if it is a number.
 126 #######################################
 127 err-exit() {
 128   exec >&2
 129   code=1
 130   if [[ "$*" ]]; then
 131     if [[ ${1/[^0-9]/} == "$1" ]]; then
 132       code=$1
 133       if [[ $2 ]]; then
 134         printf '%s\n' "$2" >&2
 135       fi
 136     else
 137       printf '%s\n' "$0: $1" >&2
 138     fi
 139   fi
 140   echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}"
 141   err-bash-trace 2
 142   echo "$0: exiting with code $code"
 143   exit $err
 144 }
 145
 146 # We want this more often than not, so run it now.
 147 err-catch