Ruby-on-rails Capistrano 和 Bash：忽略命令退出状态
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Capistrano & Bash: ignore command exit status
提问by nicholaides
I'm using Capistrano run a remote task. My task looks like this:
我正在使用 Capistrano 运行远程任务。我的任务是这样的：
task :my_task do
run "my_command"
end
My problem is that if my_commandhas an exit status != 0, then Capistrano considers it failed and exits. How can I make capistrano keep going when exit when the exit status is not 0? I've changed my_commandto my_command;echoand it works but it feels like a hack.
我的问题是，如果my_command退出状态为 != 0，则 Capistrano 认为它失败并退出。当退出状态不为 0 时，如何让 capistrano 在退出时继续运行？我已经改变了my_command对my_command;echo和它的作品，但它的感觉就像一个黑客攻击。
回答by mthorley
The simplest way is to just append true to the end of your command.
最简单的方法是将 true 附加到命令的末尾。
task :my_task do
run "my_command"
end
Becomes
成为
task :my_task do
run "my_command; true"
end
回答by Ciryon
回答by mrflip
The +grep+ command exits non-zero based on what it finds. In the use case where you care about the output but don't mind if it's empty, you'll discard the exit state silently:
+grep+ 命令根据它找到的内容退出非零。在您关心输出但不介意它是否为空的用例中，您将静默丢弃退出状态：
run %Q{bash -c 'grep #{escaped_grep_command_args} ; true' }
Normally, I think the first solution is just fine -- I'd make it document itself tho:
通常，我认为第一个解决方案很好——我会让它自己记录下来：
cmd = "my_command with_args escaped_correctly"
run %Q{bash -c '#{cmd} || echo "Failed: [#{cmd}] -- ignoring."'}
回答by Sarah Mei
You'll need to patch the Capistrano code if you want it to do different things with the exit codes; it's hard-coded to raise an exception if the exit status is not zero.
如果你想让 Capistrano 代码用退出代码做不同的事情，你需要修补它；如果退出状态不为零，则它是硬编码的以引发异常。
Here's the relevant portion of lib/capistrano/command.rb. The line that starts with if (failed... is the important one. Basically it says if there are any nonzero return values, raise an error.
这是 lib/capistrano/command.rb 的相关部分。以if (failed...开头的那一行很重要。基本上它说如果有任何非零返回值，则引发错误。
# Processes the command in parallel on all specified hosts. If the command
# fails (non-zero return code) on any of the hosts, this will raise a
# Capistrano::CommandError.
def process!
loop do
break unless process_iteration { @channels.any? { |ch| !ch[:closed] } }
end
logger.trace "command finished" if logger
if (failed = @channels.select { |ch| ch[:status] != 0 }).any?
commands = failed.inject({}) { |map, ch| (map[ch[:command]] ||= []) << ch[:server]; map }
message = commands.map { |command, list| "#{command.inspect} on #{list.join(',')}" }.join("; ")
error = CommandError.new("failed: #{message}")
error.hosts = commands.values.flatten
raise error
end
self
end
回答by Besi
I find the easiest option to do this:
我找到了最简单的方法来做到这一点：
run "my_command || :"
Notice: :is the NOP command so the exit code will simply be ignored.
注意：:是 NOP 命令，因此退出代码将被忽略。
回答by Terry
I just redirect STDERR and STDOUT to /dev/null, so your
我只是将 STDERR 和 STDOUT 重定向到 /dev/null，所以你的
run "my_command"
becomes
变成
run "my_command > /dev/null 2> /dev/null"
this works for standard unix tools pretty well, where, say, cp or ln could fail, but you don't want to halt deployment on such a failure.
这对于标准的 unix 工具非常有效，比如 cp 或 ln 可能会失败，但您不想在这种失败时停止部署。
回答by newdark-it
I not sure what version they added this code but I like handling this problem by using raise_on_non_zero_exit
我不确定他们添加了这个代码的版本，但我喜欢通过使用来处理这个问题 raise_on_non_zero_exit
namespace :invoke do
task :cleanup_workspace do
on release_roles(:app), in: :parallel do
execute 'sudo /etc/cron.daily/cleanup_workspace', raise_on_non_zero_exit: false
end
end
end
Here is where that feature is implemented in the gem. https://github.com/capistrano/sshkit/blob/4cfddde6a643520986ed0f66f21d1357e0cd458b/lib/sshkit/command.rb#L94
这是在 gem 中实现该功能的地方。 https://github.com/capistrano/sshkit/blob/4cfddde6a643520986ed0f66f21d1357e0cd458b/lib/sshkit/command.rb#L94
