Add "exec" action to allow execution of arbitrary commands with the app's environment.

lib/foreman/cli.rb

@@ -53,7 +53,18 @@ class Foreman::CLI < Thor
     error "no processes defined" unless engine.procfile.entries.length > 0
     display "valid procfile detected (#{engine.procfile.process_names.join(', ')})"
   end
+  
+  desc "exec COMMAND", "Run a command using your application's environment"
 
+  def exec(*args)
+    engine.apply_environment!
+    Kernel.exec args.join(" ")
+  rescue Errno::EACCES
+    error "not executable: #{args.first}"
+  rescue Errno::ENOENT
+    error "command not found: #{args.first}"
+  end
+  
 private ######################################################################
 
   def check_procfile!

spec/foreman/cli_spec.rb

@@ -89,5 +89,54 @@ describe "Foreman::CLI" do
       end
     end
   end
+  
+  describe "exec" do
+    describe "with a valid Procfile" do
+      before { write_procfile }
+
+      describe "and a command" do
+        let(:command) { ["ls", "-l"] }
+        
+        before(:each) do
+          stub(Kernel).exec
+        end
+        
+        it "should load the environment file" do
+          write_env
+          preserving_env do
+            subject.exec *command
+            ENV["FOO"].should == "bar"
+          end
+          
+          ENV["FOO"].should be_nil
+        end
+        
+        it "should execute the command as a string" do
+          mock(Kernel).exec(command.join(" "))
+          subject.exec *command
+        end
+      end
+      
+      describe "and a non-existent command" do
+        let(:command) { "iuhtngrglhulhdfg" }
+        
+        it "should print an error" do
+          mock_error(subject, "command not found: #{command}") do
+            subject.exec command
+          end
+        end
+      end
+      
+      describe "and a non-executable command" do
+        let(:command) { __FILE__ }
+        
+        it "should print an error" do
+          mock_error(subject, "not executable: #{command}") do
+            subject.exec command
+          end
+        end
+      end
+    end
+  end
 
 end

spec/helper_spec.rb

@@ -0,0 +1,18 @@
+require "spec_helper"
+
+describe "spec helpers" do
+  describe "#preserving_env" do
+    after { ENV.delete "FOO" }
+    
+    it "should remove added environment vars" do
+      preserving_env { ENV["FOO"] = "baz" }
+      ENV["FOO"].should == nil
+    end
+    
+    it "should reset modified environment vars" do
+      ENV["FOO"] = "bar"
+      preserving_env { ENV["FOO"] = "baz"}
+      ENV["FOO"].should == "bar"
+    end
+  end
+end

spec/spec_helper.rb

@@ -63,6 +63,16 @@ def example_export_file(filename)
   data
 end
 
+def preserving_env
+  old_env = ENV.to_hash
+  begin
+    yield
+  ensure
+    ENV.clear
+    ENV.update(old_env)
+  end
+end
+
 RSpec.configure do |config|
   config.color_enabled = true
   config.include FakeFS::SpecHelpers