From 172b967b8de7c54bd91dcb2146b91f7c45ccbcc4 Mon Sep 17 00:00:00 2001
From: Andy Boyett <andy.boyett@gmail.com>
Date: Wed, 28 Feb 2018 01:06:35 -0800
Subject: [PATCH] Add --pidslimit arg to limit max processes

The Docker API has offered support for a HostConfig.PidsLimit parameter
to the POST /containers/create route since API version 1.23. This
parameter allows limiting the maximum number of simultaneous processes
within the container.

This feature requires Linux kernel 4.3 or later and pids cgroup support.
Docker API 1.23 is known to be supported in Docker Engine 1.11.2 and
later.

This feature was tested by running `./bin.js alpine --pidslimit 10` on
the host and then running the following inside the spawned container:

    / # for i in $(seq 15) ; do
    > eval "echo sleep \$i" ; sleep 10 &
    > done
    sleep 1
    sleep 2
    sleep 3
    sleep 4
    sleep 5
    sleep 6
    sleep 7
    sleep 8
    sleep 9
    /bin/sh: can't fork
---
 bin.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/bin.js b/bin.js
index 57f3957..7cae439 100755
--- a/bin.js
+++ b/bin.js
@@ -18,6 +18,7 @@ if (argv.help || !image) {
   console.log('  --docker,  -d  [$DOCKER_HOST]  (optional host of the docker daemon)')
   console.log('  --persist                      (allow persistance of /root in the containers)')
   console.log('  --dockerport                   (expose a docker container port to dockerhost)')
+  console.log('  --pidslimit N                  (limit spawned containers to N number of processes)')
   console.log('')
   return process.exit(argv.help ? 0 : 1)
 }
@@ -26,6 +27,10 @@ if (argv.hostNetworking) argv.beforeCreate = function (config) {
   config.HostConfig.NetworkMode = 'host'
 }
 
+if (argv.pidslimit) argv.beforeCreate = function (config) {
+  config.HostConfig.PidsLimit = argv.pidslimit
+}
+
 var server = docker(image, argv)
 
 server.on('spawn', function(container) {