Why am I getting a Psych error when trying to deploy with capistrano?

Question

I am currently setting up capistrano in my Rails 3.2.13 app. I am getting the below error/details (including "control characters are not allowed at line 1 column 1"). I have done some searching for this but do not see anything related to me.

I am using rvm-capistrano and ruby 2.0.0-p195. I recently moved my app-required environment variables into .bashrc.

...      
* 2013-06-10 15:18:32 executing `deploy:assets:update_asset_mtimes'
      * executing "[ -e /home/deployer/apps/super_rad_app/shared/assets/manifest* ] && cat /home/deployer/apps/super_rad_app/shared/assets/manifest* || echo"
        servers: ["107.20.249.163"]
        [107.20.249.163] executing command
        command finished in 6238ms
    *** [deploy:update_code] rolling back
      * executing "rm -rf /home/deployer/apps/super_rad_app/releases/20130610221258; true"
        servers: ["107.20.249.163"]
        [107.20.249.163] executing command
     ** [out :: 107.20.249.163] Using /home/deployer/.rvm/gems/ruby-2.0.0-p195
        command finished in 6623ms
    /home/nate/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/psych.rb:205:in `parse': (<unknown>): control characters are not allowed at line 1 column 1 (Psych::SyntaxError)
        from /home/nate/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
        from /home/nate/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/psych.rb:153:in `parse'
        from /home/nate/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/psych.rb:129:in `load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/recipes/deploy/assets.rb:26:in `parse_manifest'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:191:in `method_missing'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:191:in `method_missing'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/recipes/deploy/assets.rb:93:in `block (3 levels) in load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `instance_eval'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `invoke_task_directly'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:25:in `invoke_task_directly_with_callbacks'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:89:in `execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:101:in `find_and_execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/callback.rb:38:in `call'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `block in trigger'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `each'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `trigger'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:23:in `invoke_task_directly_with_callbacks'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:89:in `execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:101:in `find_and_execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/callback.rb:38:in `call'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `block in trigger'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `each'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:141:in `trigger'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:27:in `invoke_task_directly_with_callbacks'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:89:in `execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:191:in `method_missing'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:110:in `block in define_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/recipes/deploy.rb:234:in `block (3 levels) in load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:56:in `transaction'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:191:in `method_missing'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/recipes/deploy.rb:233:in `block (2 levels) in load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `instance_eval'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `invoke_task_directly'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:25:in `invoke_task_directly_with_callbacks'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:89:in `execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:191:in `method_missing'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/namespaces.rb:110:in `block in define_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/recipes/deploy.rb:201:in `block (2 levels) in load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `instance_eval'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:138:in `invoke_task_directly'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/callbacks.rb:25:in `invoke_task_directly_with_callbacks'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:89:in `execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/configuration/execution.rb:101:in `find_and_execute_task'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/execute.rb:46:in `block in execute_requested_actions'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/execute.rb:45:in `each'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/execute.rb:45:in `execute_requested_actions'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/help.rb:19:in `execute_requested_actions_with_help'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/execute.rb:34:in `execute!'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/lib/capistrano/cli/execute.rb:14:in `execute'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/gems/capistrano-2.15.4/bin/cap:4:in `<top (required)>'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/bin/cap:23:in `load'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/bin/cap:23:in `<main>'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/bin/ruby_noexec_wrapper:14:in `eval'
        from /home/nate/.rvm/gems/ruby-2.0.0-p195/bin/ruby_noexec_wrapper:14:in `<main>'

Answer 1

This comes from a possible problem in your .bashrc. Check this question for additional details: psych.rb error when deploying with Capistrano 'mapping not allowed in this context'

Answer 2

I also had this problem, but for a different reason. We are using rvm-capistrano, and our project has a .rvmrc file. The deploy:assets:update_asset_mtimes Capistrano task runs a shell command on the server to capture the contents of the assets manifest. The presence of the .rvmrc file in the deploy generated a "You are using '.rvmrc', it requires trusting..." warning from RVM, which inadvertently became part of the output of the shell command. I only saw this after instrumenting the assets.rb recipe in my local capistrano gem with a puts statement.

I fixed my issue by running "rvm rvmrc warning ignore all.rvmrcs" on the server, and then deploying again.

Another option would be to switch away from .rvmrc and the whole trusting thing to use the .ruby-version approach. See Use rvmrc or ruby-version file to set a project gemset with RVM? for details.