Erlang - starting VM'/Nodes with accompanying command

Question

I am in the process of testing a small system.

It is very time consuming each time I make a change because I need to:

1. Start 4 Erlang Nodes/Vms with specific names
2. Run a single line of code on each of them
   • messenger:start_server().
   • messenger:start_router().
   • messenger:logon(steven).
   • messenger:logon(dave).

Each one of those lines is executed on a different node.

Is there anyway I can automate things? I was looking at boot scripts but I cannot find anything that is simple and relative to me

Answer 1

You can try to create simple bash script:

#! /bin/bash

NAME=node1
mkdir -p /tmp/$NAME
run_erl -daemon /tmp/$NAME /tmp/$NAME erl -sname $NAME -eval "ok = messenger:start_server()"

NAME=node2
mkdir -p /tmp/$NAME
run_erl -daemon /tmp/$NAME /tmp/$NAME erl -sname $NAME -eval "ok = messenger:start_router()"

NAME=node3
mkdir -p /tmp/$NAME
run_erl -daemon /tmp/$NAME /tmp/$NAME erl -sname $NAME -eval "ok = messenger:logon(steven)"

NAME=node4
mkdir -p /tmp/$NAME
run_erl -daemon /tmp/$NAME /tmp/$NAME erl -sname $NAME -eval "ok = messenger:logon(dave)."

All output from node you can find in /tmp/nodeN directory. You can connect to the node with following bash command:

erl -sname 'test@your-host-name' -remsh 'nodeN@your-host-name'

You can find more info in erl man and run_erl man.