Allow passing a region to cuffdown.

lib/cuffbase.rb

@@ -1,6 +1,12 @@
 require 'yaml'
 
 module CuffBase
+  def self.shared_cli_args(opts, args)
+    opts.on('--region=aws_region', 'AWS region, overrides env variable AWS_REGION') do |region|
+      args[:aws_region] = region
+    end
+  end
+
   def self.empty_from_template(io)
     self.template_parameters(io) {|_| nil }
   end

lib/cuffdown/main.rb

@@ -1,8 +1,23 @@
+require 'cuffbase'
 require 'cuffsert/metadata'
 require 'cuffsert/rxcfclient'
+require 'optparse'
 require 'yaml'
 
 module CuffDown
+  def self.parse_cli_args(argv)
+    args = {}
+    parser = OptionParser.new do |opts|
+      opts.banner = 'Output CuffSert-formatted metadata from an existing stack.'
+      opts.separator('')
+      opts.separator('Usage: cuffdown stack-name')
+      CuffBase.shared_cli_args(opts, args)
+    end
+    stackname, _ = parser.parse(argv)
+    args[:stackname] = stackname
+    args
+  end
+
   def self.parameters(stack)
     (stack[:parameters] || []).map do |param|
       {
@@ -31,10 +46,11 @@ def self.dump(name, params, tags, output)
     YAML.dump(result, output)
   end
 
-  def self.run(args, output)
+  def self.run(argv, output)
+    cli_args = self.parse_cli_args(argv)
     meta = CuffSert::StackConfig.new
-    meta.stackname = args[0]
-    client = CuffSert::RxCFClient.new({})
+    meta.stackname = cli_args[:stackname]
+    client = CuffSert::RxCFClient.new(cli_args[:aws_region])
     stack = client.find_stack_blocking(meta)
     unless stack
       STDERR.puts "No such stack #{meta.stackname}"

lib/cuffsert/cli_args.rb

@@ -1,4 +1,5 @@
 require 'optparse'
+require 'cuffbase'
 require 'cuffsert/version'
 
 module CuffSert
@@ -23,6 +24,9 @@ def self.parse_cli_args(argv)
       opts.separator('  cuffsert --name <stackname> {--parameter Name=Value | --tag Name=Value}... [stack.json]')
       opts.separator('  cuffsert --metadata <metadata.json> --selector <path/in/metadata> stack.json')
       opts.separator('  cuffsert --metadata <metadata.json> --selector <path/in/metadata> {--parameter Name=Value | --tag Name=Value}... [stack.json]')
+
+      CuffBase.shared_cli_args(opts, args)
+
       opts.on('--metadata path', '-m path', 'Yaml file to read stack metadata from') do |path|
         path = '/dev/stdin' if path == '-'
         unless File.exist?(path)
@@ -64,10 +68,6 @@ def self.parse_cli_args(argv)
         args[:overrides][:tags][key] = val
       end
 
-      opts.on('--region=aws_region', 'AWS region, overrides env variable AWS_REGION') do |region|
-        args[:aws_region] = region
-      end
-
       opts.on('--s3-upload-prefix=prefix', 'Templates > 51200 bytes are uploaded here. Format: s3://bucket-name/[pre/fix]') do |prefix|
         unless prefix.start_with?('s3://')
           raise "Upload prefix #{prefix} must start with s3://"

spec/cuffdown/main_spec.rb

@@ -26,5 +26,13 @@
     it 'outputs parameter values for the stack' do
       expect(output.string).to match(/Name: p1.*Value: v1/m)
     end
+
+    context 'when invoked with an explicit region' do
+      let(:cli_args) { ['--region', 'rp-north-1', 'stack-name'] }
+
+      it 'passes region to the ClodFormation client' do
+        expect(Aws::CloudFormation::Client).to have_received(:new).with(hash_including(:region => 'rp-north-1'))
+      end
+    end
   end
-end
+end