How to avoid generating content with quotes from an erb template? - ruby

Question

I have written an erb template which I'm using to generate a Dockerfile dynamically. Here is how the whole thing works:
Take the input from command line.
Create an ruby array out of the input.
Use the Dockerfile.erb to generate Dockerfile based of this input.
The problem that I face here is that when the input is copied onto the generated Dockerfile, it has quotes around it which I need to avoid. Is there a way to do so?
Dockerfile.erb
FROM docker.cernerrepos.net/alpine:3.7 AS builder
LABEL bundles=<%= keys[:bundles] %>
generate.rb
require 'optparse'
require 'erb'
DEBUG_PREFIX = '>>> generate_dockerfile.rb ->'
#options = {}
#options[:output]= '.'
optparse = OptionParser.new do |opts|
opts.banner = 'Usage: generate_dockerfile.rb [options]'
opts.on('-b [BUNDLES]', '--bundles [BUNDLES]', "Comma separated list of bundles without extension and version.") do |bundles|
#options[:bundles] = bundles.split(',')
end
opts.on('-h', '--help', 'Display this Help') do
puts opts
exit
end
end
optparse.parse!
keys = #options
File.open('Dockerfile', 'w+') do |f|
f.write(ERB.new(File.read('Dockerfile.erb'), nil, '-').result(binding))
end
Actual Output Dockerfile
FROM docker.cernerrepos.net/alpine:3.7 AS builder
LABEL bundles=["sample_bundle1", "sample_bundle2"]
Expected Output Dockerfile
FROM docker.cernerrepos.net/alpine:3.7 AS builder
LABEL bundles=[sample_bundle1, sample_bundle2]
Command to Execute
ruby generate.rb -b sample_bundle1,sample_bundle2
Edit 1: Modified the question to include the minimum sample code, the expected out and the actual output and the command to run the code.

Answer 1

Right here:
LABEL bundles=<%= keys[:bundles] %>
You are basically calling keys[:bundle].to_s and interpolating that in the result.
What's ["foo", "bar"].to_s? It's ["foo", "bar"] (with quotes!)
That's why you're getting this result.
You can change it to the following, if you want to remove the quotations:
LABEL bundles=[<%= keys[:bundles].join(", ") %>]
Not to say this is the wrong approach, but isn't really a typical thing to do, so I don't think there's another built-in way to do this.