Ben Biddington

Whatever it is, it's not about "coding"

Posts Tagged ‘automated-acceptance-testing

TeamCity — rake runner aborts early

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How to run TeamCity rakerunner locally

It is important to get the working directory right, otherwise you’ll get a bunch of require errors, for example:

C:\ruby\bin/ruby.exe C:\BuildAgent\plugins\rake-runner\lib\rb\runner\rakerunner.rb

Fails with error:

C:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require’: no such file to load — teamcity/rakerunner_consts (LoadError)
from C:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require’
from C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:20
no such file to load -- teamcity/rakerunner_consts (LoadError)

from C:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'

from C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:20

rake_ext is including a file with path:

require 'teamcity/rakerunner_consts'

And we know require works relative to the working directory which means our working directory must be set to:

C:\BuildAgent\plugins\rake-runner\lib\rb\patch

Rake abort

TeamCity rakerunner exits with message “Rake aborted!” as soon as it encounters a non-zero exit code from any task. Any subsequent tasks are therefore skipped.

This is not desirable behaviour for us because we have reporting tasks that must run always.

Stack trace showing the overridden members:

C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:158:in 'process_exception'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:95:in 'target_exception_handling'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:266:in 'execute'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:578:in 'invoke_with_call_chain'
C:/ruby/lib/ruby/1.8/monitor.rb:242:in 'synchronize'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:571:in 'invoke_with_call_chain'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:564:in 'standard_invoke_with_call_chain'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:235:in 'invoke'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:90:in 'target_exception_handling'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:234:in 'invoke'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2027:in 'invoke_task'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in 'top_level'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in 'each'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in 'top_level'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:311:in 'standard_exception_handling'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1999:in 'top_level'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1977:in 'run'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:311:in 'standard_exception_handling'
C:/ruby/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1974:in 'run'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:179:in 'run'
C:/BuildAgent/plugins/rake-runner/lib/rb/runner/rakerunner.rb:40

Here’s what rake Application.top_level looks like:

# Rake lib
def top_level
    standard_exception_handling do
        if options.show_tasks
            display_tasks_and_comments
        elsif options.show_prereqs
            display_prerequisites
        else
            top_level_tasks.each { |task_name| invoke_task(task_name) }
        end
    end
end

The TeamCity version has overridden standard_exception_handling:

# TeamCity Rakerunner
def standard_exception_handling
    begin
        yield
    rescue Rake::ApplicationAbortedException => app_e
        raise
    rescue Exception => exc
        Rake::TeamCityApplication.process_exception(exc)
    end
end

So the yield there is yielding to the result of executing each top level task. The rake task implementation has an execute method like:

# TeamCity Rakerunner
def execute(*args, &block)
    standard_execute_block = Proc.new do
        standard_execute(*args, &block)
    end

    if application.options.dryrun
        Rake::TeamCityApplication.target_exception_handling(
            name, true, "(dry run)", &standard_execute_block)
    else
        Rake::TeamCityApplication.target_exception_handling(
            name, true, &standard_execute_block)
    end
end

Where Rake::TeamCityApplication.target_exception_handling raises Rake::ApplicationAbortedException. We can disable this behaviour by commenting it out.

Solution

The Quick solution is to comment out the line that raises the exception:

# rake_ext line 158, method TeamCityApplication.process_exception
raise Rake::ApplicationAbortedException, exc

The problem now though, is that a failing task will not be reported automatically.

In this project that’s fine because we’re doing this ourselves in a subsequent step, but for other projects using the rakerunner this may prove confusing.

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Written by benbiddington

18 May, 2009 at 12:19

Rake — shell task failure

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For my current project, we’re running cucumber as one of our tasks. Our report generation runs afterwards — which we need to happen regardless of cucumber’s exit code (cucumber exits with code 1 when any tests fail).

Handling shell task failure

We noticed that if cucumber fails, rake exits immediately — without running our subsequent report tasks.

We’re running cucumber with rake’s ruby function — which runs the ruby interpreter in its own process by invoking a shell command.

Pseudo-stacktrace (irrelevant source lines omitted):

Shell::CommandProcessor.system(command, *opts)
Rake::Win32.rake_system(*cmd)
FileUtils.sh(*args, &block)
FileUtils.ruby(*args, &block)

The key to this is the behaviour of rake’s FileUtils.sh. Examining the source shows:

If it is not supplied a block, and the shell command fails, and rake exits with error status.

Aside: For some reason, Kernel.system echoes errors.

Example

This task will cause rake to exit immediately with status 1:

task 'this-one-fails' do
    ruby("xxx")
end

while the following task does not cause rake to terminate  normally, any subsequent task will still run:

path = File.expand_path(File.dirname(__FILE__) + ‘/output/cucumber-manual.txt’)
cuke_path = ‘C:/ruby/lib/ruby/gems/1.8/gems/cucumber-0.3.3/bin/cucumber’
ruby(“#{cuke_path} -h > ‘#{path}'”) do |success, exit_code|
puts “Exited with code: #{exit_code}” if !success
end
task 'this-one-succeeds' do
    ruby("xxx") do |success, exit_code|
        puts "Exited with code: #{exit_code.exitstatus}" unless success
    end
end

Getting the last exit status

The $? variable contains the status of the last child process to terminate. This may be useful if steps subsequent to the failed one require this information.

Written by benbiddington

16 May, 2009 at 16:45

TeamCity build agents and FireWatir

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We have had some issues lately getting our automated acceptance tests running in TeamCity on Firefox.

Our failing tests could open browser windows, but not interact with them — the same behaviour exhibited when the JSSH plugin is missing. And the error reported in TeamCity is like:

Unable to connect to machine : 127.0.0.1 on port 9997.
Make sure that JSSh is properly installed and
Firefox is running with '-jssh' option
(Watir::Exception::UnableToStartJSShException)

This was puzzling because we knew we had installed JSSH.

The problem amounts to ensuring the Firefox JSSH extension is enabled for the correct account.

Build agents, user accounts and desktop (GUI) interaction

Only when Local System Account is selected can you also select the Allow service to interact with the desktop option. The “this account” method does not even allow selection of the checkbox (watch carefully, the checkbox is unchecked when you press apply).

teamcity-buildagent-account-control

Running without GUI does not prevent these types of things happening — they’re just not painted on the screen — so to diagnose issues like these it’s preferable to allow interaction with desktop.

This means running build agents as Local System account.

Solution

Firefox allows adding extensions via command line. So, to enable JSSH for every user on your build agent, download the extension, and then run something like:

$ "C:\Program Files\Mozilla Firefox\firefox -install-global-extension 'path\to\extension'"

You can then run Team City Build Agent Service as Local System user and enable desktop interaction.

References

  • [Windows Local System account] The LocalSystem account is a predefined local account used by the service control manager. This account is not recognized by the security subsystem, so you cannot specify its name in a call to the LookupAccountName function. It has extensive privileges on the local computer, and acts as the computer on the network.
  • [Firefox command line options] Various command line options are be available to perform advanced, troubleshooting or system administration tasks. Installation into the application directory is possible from the command line, intended to be used by administrators on multi-user systems.
  • [How does JSSH work?] FireWatir uses JSSh (TCP/IP JavaScript Shell Server for Mozilla) to drive the FireFox browser. JSSh allows other programs (like telnet) to establish JavaScript shell connections to a running Mozilla process. Once that connection is made, we can send JavaScript commands over the connection, which are executed against the DOM of the page loaded in the browser. JSSh listens on port 9997 by default.

Written by benbiddington

12 May, 2009 at 12:00