PS-release: PS-stretch
PS-pkg: net::approx
approx: 5.7-3

Approx is an HTTP-based proxy server for Debian-style package archives.
 It fetches files from remote repositories on demand,
 and caches them for local use.
 .
 Approx saves time and network bandwidth if you need to install or
 upgrade .deb packages for a number of machines on a local network.
 Each package is downloaded from a remote site only once,
 regardless of how many local clients install it.
 The approx cache typically requires a few gigabytes of disk space.
 .

(From: apt-cache show approx)

The Debian approx service has been designed for invokation by the “inetd”.¹⁾ It cannot be run from the commandline. However in version 5.7-1 approx was patched for use with the “systemd.socket” service. ²⁾

In Debian stretch approx is invoked by “systemd.socket” by default.

# systemctl stop approx.socket

# systemctl start approx.socket

# systemctl status approx.socket
* approx.socket - caching proxy server for Debian archive files
   Loaded: loaded (/lib/systemd/system/approx.socket; enabled; vendor preset: en
   Active: active (listening) since Thu 2018-12-20 19:01:05 UTC; 1 day 16h ago
     Docs: man:approx(8)
   Listen: [::]:80 (Stream)
 Accepted: 18; Connected: 0

# systemctl list-units approx.socket
UNIT          LOAD   ACTIVE SUB       DESCRIPTION                               
approx.socket loaded active listening caching proxy server for Debian archive fi

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

• More info: $ man systemctl

/etc/approx/approx.conf:

debian      http://deb.debian.org/debian
security    http://security.debian.org/debian-security

Principally Debian approx can be used for cacheing every file-based repository:

mozilla     http://ftp.mozilla.org/pub

Now in a script you can do:

$ curl -o firefox-64.0.tar.bz2 http://approx:9999/mozilla/firefox/releases/64.0/linux-x86_64/en-US/firefox-64.0.tar.bz2

Enable debugging:

$debug      true

• Since every request launches a new approx instance, changes take effect immediately. No service restart is needed.

/lib/systemd/system/approx.socket:

[Socket]
# ListenStream=9999
ListenStream=80

Restart service:

# systemctl daemon-reload

# systemctl restart approx.socket

Copyright © 2018 Tux4u.be - Author: Marjan Waldorp; debian-approx.md 2018-12-22