iankelling.org Git - distro-setup/blob - filesystem/etc/apt/detect-http-proxy

   1 #!/bin/bash
   2 # I, Ian Kelling, follow the GNU license recommendations at
   3 # https://www.gnu.org/licenses/license-recommendations.en.html. They
   4 # recommend that small programs, < 300 lines, be licensed under the
   5 # Apache License 2.0. This file contains or is part of one or more small
   6 # programs. If a small program grows beyond 300 lines, I plan to switch
   7 # its license to GPL.
   8
   9 # Copyright 2024 Ian Kelling
  10
  11 # Licensed under the Apache License, Version 2.0 (the "License");
  12 # you may not use this file except in compliance with the License.
  13 # You may obtain a copy of the License at
  14
  15 #     http://www.apache.org/licenses/LICENSE-2.0
  16
  17 # Unless required by applicable law or agreed to in writing, software
  18 # distributed under the License is distributed on an "AS IS" BASIS,
  19 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  20 # See the License for the specific language governing permissions and
  21 # limitations under the License.
  22
  23 # based on
  24 # http://askubuntu.com/questions/53443/how-do-i-ignore-a-proxy-if-not-available
  25 # altered because testing a down proxy takes like 2 seconds,
  26 # and we would do it like 100 times in a row. so cache a failed result
  27 # locally for 10 minutes. Also, using newer option based on man apt.conf.
  28 #
  29 # Once when I was testing, it seemed I needed to have it output
  30 # DIRECT after outputing the proxy url
  31
  32 # note, the url we are trying to fetch is $1
  33
  34 # note, if there is a problem, some ways to debug:
  35 # first,
  36 # edit /etc/apt/apt.conf.d/02proxy
  37 # add, remove the autodetec
  38 # Acquire::http::proxy "http://CacheServerIp:3142";
  39 # see the /var/log/apt-cacher-ng logs
  40 # read
  41 # file:///usr/share/doc/apt-cacher-ng/html/index.html
  42
  43 proxy_host=faiserver
  44 proxy_port=3142
  45 proxy_url=http://$proxy_host:$proxy_port/
  46 f=/tmp/apt_proxy_fail
  47 if [[ ! -w /tmp ]]; then
  48     echo DIRECT
  49     exit 0
  50 fi
  51 modtime=$(stat -c %Y $f 2>/dev/null ) ||:
  52 if [[ $modtime ]] && (( $(( EPOCHSECONDS - modtime  )) < 60*10 )); then
  53     echo DIRECT
  54     exit 0
  55 else
  56     rm -f $f
  57 fi
  58 if getent hosts $proxy_host &>/dev/null && timeout 1 nc -z $proxy_host $proxy_port &>/dev/null; then
  59     echo $proxy_url
  60 else
  61     if [[ ! -e $f || -w $f ]]; then
  62         touch $f
  63     fi
  64 fi