输出管理

注解

All levels, save for debug and exceptions, are on by default.

Standard output levels¶

The standard, atomic output levels/groups are as follows:

• status: Status messages, i.e. noting when Fabric is done running, if the user used a keyboard interrupt, or when servers are disconnected from. These messages are almost always relevant and rarely verbose.
• aborts: Abort messages. Like status messages, these should really only be turned off when using Fabric as a library, and possibly not even then. Note that even if this output group is turned off, aborts will still occur – there just won’t be any output about why Fabric aborted!
• warnings: Warning messages. These are often turned off when one expects a given operation to fail, such as when using grep to test existence of text in a file. If paired with setting env.warn_only to True, this can result in fully silent warnings when remote programs fail. As with aborts, this setting does not control actual warning behavior, only whether warning messages are printed or hidden.
• running: Printouts of commands being executed or files transferred, e.g. [myserver] run: ls /var/www. Also controls printing of tasks being run, e.g. [myserver] Executing task 'foo'.
• stdout: Local, or remote, stdout, i.e. non-error output from commands.
• stderr: Local, or remote, stderr, i.e. error-related output from commands.
• user: User-generated output, i.e. local output printed by fabfile code via use of the fastprint or puts functions.

Debug output¶

There are two more atomic output levels for use when troubleshooting: debug, which behaves slightly differently from the rest, and exceptions, whose behavior is included in debug but may be enabled separately.

• debug: Turn on debugging (which is off by default.) Currently, this is largely used to view the “full” commands being run; take for example this run call:

  run('ls "/home/username/Folder Name With Spaces/"')
  

  Normally, the running line will show exactly what is passed into run, like so:

  [hostname] run: ls "/home/username/Folder Name With Spaces/"
  

  With debug on, and assuming you’ve left shell set to True, you will see the literal, full string as passed to the remote server:

  [hostname] run: /bin/bash -l -c "ls \"/home/username/Folder Name With Spaces\""
  

  Enabling debug output will also display full Python tracebacks during aborts (as if exceptions output was enabled).

  注解

  Where modifying other pieces of output (such as in the above example where it modifies the ‘running’ line to show the shell and any escape characters), this setting takes precedence over the others; so if running is False but debug is True, you will still be shown the ‘running’ line in its debugging form.

• exceptions: Enables display of tracebacks when exceptions occur; intended for use when debug is set to False but one is still interested in detailed error info.

Output level aliases¶

In addition to the atomic/standalone levels above, Fabric also provides a couple of convenience aliases which map to multiple other levels. These may be referenced anywhere the other levels are referenced, and will effectively toggle all of the levels they are mapped to.

• output: Maps to both stdout and stderr. Useful for when you only care to see the ‘running’ lines and your own print statements (and warnings).
• everything: Includes warnings, running, user and output (see above.) Thus, when turning off everything, you will only see a bare minimum of output (just status and debug if it’s on), along with your own print statements.
• commands: Includes stdout and running. Good for hiding non-erroring commands entirely, while still displaying any stderr output.