Parsing command line arguments via GetoptLong.

dup.rb

@@ -2,6 +2,8 @@
 require 'yaml'
 require 'pp'
 require 'shellwords'
+require 'getoptlong'
+
 
 def get_sample(name="container")
 	return <<~HEREDOC
@@ -49,46 +51,42 @@ def get_sample(name="container")
 		HEREDOC
 end
 
-if ARGV[0]=="--sample"
+def action_sample
 	puts get_sample
 	exit 1
 end
 
+def action_help
+	puts "-h, --help              Show this help."
+	puts "-n, --dry-run           Don't execute any commands."
+	puts "-s, --sample            Outputs a sample yml file."
+	puts "-c, --create            Create a new container yml file."
+	exit 1
+end
+
 def run(cmd, ignore_returnvalue=false)
 	puts "+ #{cmd}"
-	returnvalue = true
+	returnvalue = $dry_run ? true : system(cmd)
-	returnvalue = system(cmd)
 	raise "Command returned a non-zero exit value." if returnvalue!=true && !ignore_returnvalue
 end
 
-if ARGV[0]=="--create"
+def action_create(container, file)
-	filename = ARGV[1]
-else
-	filename = ARGV[0]
-end
-
-if filename==nil || filename==""
-	raise "No name given."
-end
-
-file = "%s/%s.yml" % [ "/data/fabian/projects/dup", filename ]
-
-if ARGV[0]=="--create"
 	raise "File #{file} already exists" if File.exists?(file)
 	
-	File.open(file, "w") {|f| f.write(get_sample(filename))}
+	File.open(file, "w") {|f| f.write(get_sample(container))}
 	
 	exec("joe #{file.shellescape}")
 	exit 1 # will never be reached because exec replaces this process. But just in case... ;-)
 end
 
-raise "File #{file} not found." unless File.exists?(file)
+def action_run(container, file)
+	raise "File #{file} not found." unless File.exists?(file)
 
-data = File.open(file, "r") {|f| YAML.load(f.read)}
+	data = File.open(file, "r") {|f| YAML.load(f.read)}
 
-raise "Expected #{file} to define (at least) a container named #{filename}." unless data.has_key?(filename)
+	raise "Expected #{file} to define (at least) a container named #{container}." unless data.has_key?(container)
 
-data.each do |key, data|
+	data.each do |key, data|
 		if data["build"]
 			(data["before_build"] || []).each{|cmd| run(cmd)}
 			cmd = ["docker", "build", "-t", data["image"].shellescape, data["build"].shellescape]
@@ -120,4 +118,46 @@ data.each do |key, data|
 		run(cmd.join(" "))
 		
 		(data["after_run"] || []).each{|cmd| run(cmd)}
+	end
 end
+
+action = :run
+container = nil
+$dry_run = false
+
+opts = GetoptLong.new(
+	[ '--sample', '-s', GetoptLong::NO_ARGUMENT ],
+	[ '--create', '-c', GetoptLong::NO_ARGUMENT ],
+	[ '--help', '-h', GetoptLong::NO_ARGUMENT ],
+	[ '--dry-run', '-n', GetoptLong::NO_ARGUMENT ]
+)
+
+opts.each do |opt, arg|
+	case opt
+		when '--sample'
+			action_sample
+		when '--create'
+			action = :create
+		when '--help'
+			action_help
+		when '--dry-run'
+			puts "Dry-run. Not going to execute any command."
+			$dry_run = true
+	end
+end
+
+container = ARGV.shift
+
+if container==nil || container==""
+	raise "No container given."
+end
+
+file = "%s/%s.yml" % [ "/data/fabian/projects/dup", container ]
+
+if action == :create
+	action_create(container, file)
+elsif action == :run
+	action_run(container, file)	
+end
+
+