Aduril
Scripting with User Switch Command
Hello there,
to improve the workflow of my team I want to make it easier for them to connect to a remote system (aka our stage environment and our production environment).
Currently the workflow looks as following
./start-iex me 127.0.0.1 #script that set cookies and stuff
iex(me@127.0.0.1)1> Node.connect :"app@IP.OF.STAGE.ENV"
true
iex(me@127.0.0.1)3> #CTRL+G
User switch command
--> r 'app@IP.OF.STAGE.ENV'
--> c 2
Eshell V10.5 (abort with ^G)
(app@IP.OF.STAGE.ENV)1> #CTRL+G again
User switch command
--> r 'app@IP.OF.STAGE.ENV' 'Elixir.IEx'
--> c 3
iex(app@IP.OF.STAGE.ENV)1> #iex shell on remote system
As you can see this is rather tedious and error prone (how often I used the wrong quotes here…).
So my question is:
Does anybody know a way to enter the User Switch Command in a way that is scriptable. My overall goal would be a script that allows people to simply connect to one of our deployed stages.
Any ideas?
Marked As Solved
Nicd
I have used Expect for this, as it is designed for automating usage of interactive programs.
I no longer use the script but here it is for reference: refresh.exp · master · Mikko Ahlroth / mebe · GitLab – it should help you get started in case you go with Expect.
Note that on line 14, send " " sends the ctrl+g IIRC. It may not be copied correctly if you copy it with a browser so you may want to download the file directly. (And indeed if I copy it to this forum, it’s rendered as send "a"!)
EDIT: Note that there is also a --remsh option for IEx. Maybe that already does what you need, at least partly?
Also Liked
Aduril
Thanks @Nicd,
I have implemented it as expect-script now and will try to improve it. For others with a similar problem, here is my current solution that seems to do the trick:
set username [lindex $argv 0]
set app_ip [lindex $argv 1]
spawn ./start-iex $username
expect "iex" { send "Node.connect :\"app@$app_ip\"" }
expect "iex" { send "^G" } # this might break while copy-pasting - it is the CTRL+G command
expect -- " -->" { send "r 'app@$app_ip' \n" }
expect -- " -->" { send "c 2\n" }
expect "(app@*" { send "^G" } # see above
expect -- " -->" { send "r 'app@$app_ip' 'Elixir.IEx'\n" }
expect -- " -->" { send "c 3\n" }
interact
I have not used expect before, so if you see any unnecessary parts let me know 
.
And if anybody knows a way to enter the user switch command mode within an elixir script, let me know.
Last Post!
BlindingDark
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Practical resources that improve the lives of professional developers.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #elixirconf-us
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #metaprogramming
- #security
- #hex
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Error tracking for Elixir devs who love to ship. Start your free account.
Practical resources that improve the lives of professional developers.
Develop your skills with books, videos, and courses.
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"