YAML / JSON difference in watch behaviour

Hello everyone. Thanks for your work.

What's going wrong?

When I use ecosystem.config.js it works ok.

  apps : [
    {
      script: "app.js",
      watch:  true,
    },

But when I switched to YAML(yeah, I know: "use JSON format if possible")

apps:
  - script: app.js
    watch: true

PM2 hangs one of my cores with 100% load and enormous writes to log file. In that log I found chokidar trying to watch all directory files (which I have millions)

I fix it changing watch: true to watch: app.js.

Just want to point to this inconsistency

How could we reproduce this issue?

#!/usr/bin/env bash
mkdir /tmp/test
cd /tmp/test
for i in {1..10000}; do touch $i; done

echo "apps:" > ecosystem.json
echo "  - script: app.js" >> ecosystem.json
echo "  - watch: true" >> ecosystem.json

echo 'console.log(1)' > app.js
pm2 start ecosystem.yaml

Supporting information

===============================================================================
--- PM2 REPORT (Mon Oct 02 2017 14:16:30 GMT+0300 (EEST)) ---------------------
===============================================================================
--- Daemon -------------------------------------------------
pm2d version         : 2.7.1
node version         : 8.6.0
node path            : undefined
argv                 : /usr/local/bin/node,/usr/local/lib/node_modules/pm2/lib/Daemon.js
argv0                : node
user                 : vganzin
uid                  : 1000
gid                  : 1000
uptime               : 22min
===============================================================================
--- CLI ----------------------------------------------------
local pm2            : 2.7.1
node version         : 8.6.0
node path            : undefined
argv                 : /usr/local/bin/node,/usr/local/bin/pm2,report
argv0                : node
user                 : vganzin
uid                  : 1000
gid                  : 1000
===============================================================================
--- System info --------------------------------------------
arch                 : x64
platform             : linux
type                 : Linux
cpus                 : Intel(R) Pentium(R) CPU 4405U @ 2.10GHz
cpus nb              : 4
freemem              : 326893568
totalmem             : 8344227840
home                 : /home/vganzin
===============================================================================

Start by running the supplied reproduction around pm2 start ecosystem.yaml and compare it with the ecosystem.config.js example. Trace how the YAML configuration reaches chokidar's watch setup, using the reported watch: true and watch: app.js cases. Done means the two configuration formats have consistent watch behavior without scanning the entire directory.