如何仅在单个主机上 运行 @roles-decorated fabric 任务
How to run a @roles-decorated fabric task on only a single host
我有一个用 @roles 装饰的任务，我偶尔想 运行 在单个主机上（用于金丝雀测试部署）。
from fabric.api import *
env.roledefs = {
'web-workers': ['django@worker1', 'django@worker2'],
'some-other-role': ['django@worker2'],
}
@task
@roles('web-workers')
def bogomips():
run('uptime')
docs for @roles 指出：
...barring an override on the command line, my_func will be executed against the hosts listed [in the role]...
但我无法使这里提到的 "override" 功能发挥作用...我试过了：
$ fab bogomips -H django@worker2
$ fab bogomips -R some-other-role
但它总是在装饰器中提到的整个角色上执行...
我在这里错过了什么？我如何覆盖 @roles 修饰的任务 运行？
根据 Execution model's Order of Precedence，这实际上是预期的行为，在此情况下您必须使用略有不同的语法。
所以这是不起作用的命令：
$ fab bogomips -R some-other-role # fabric ignores the -R values!
这是有效的版本：
$ fab bogomips:roles=some-other-role
这是问题所在：#308: @roles and @hosts decorators ignore command line options
以及文档：http://docs.fabfile.org/en/1.0.0/usage/execution.html#order-of-precedence
- Per-task, command-line host lists (fab mytask:host=host1) override absolutely everything else.
- Per-task, decorator-specified host lists (@hosts('host1')) override the env variables.
- Globally specified host lists set in the fabfile (env.hosts = ['host1']) can override such lists set on the command-line, but only if you’re not careful (or want them to.)
- Globally specified host lists set on the command-line (--hosts=host1) will initialize the env variables, but that’s it.
我有一个用 @roles 装饰的任务，我偶尔想 运行 在单个主机上（用于金丝雀测试部署）。
from fabric.api import *
env.roledefs = {
'web-workers': ['django@worker1', 'django@worker2'],
'some-other-role': ['django@worker2'],
}
@task
@roles('web-workers')
def bogomips():
run('uptime')
docs for @roles 指出：
...barring an override on the command line, my_func will be executed against the hosts listed [in the role]...
但我无法使这里提到的 "override" 功能发挥作用...我试过了：
$ fab bogomips -H django@worker2
$ fab bogomips -R some-other-role
但它总是在装饰器中提到的整个角色上执行...
我在这里错过了什么？我如何覆盖 @roles 修饰的任务 运行？
根据 Execution model's Order of Precedence，这实际上是预期的行为，在此情况下您必须使用略有不同的语法。
所以这是不起作用的命令：
$ fab bogomips -R some-other-role # fabric ignores the -R values!
这是有效的版本：
$ fab bogomips:roles=some-other-role
这是问题所在：#308: @roles and @hosts decorators ignore command line options
以及文档：http://docs.fabfile.org/en/1.0.0/usage/execution.html#order-of-precedence
- Per-task, command-line host lists (fab mytask:host=host1) override absolutely everything else.
- Per-task, decorator-specified host lists (@hosts('host1')) override the env variables.
- Globally specified host lists set in the fabfile (env.hosts = ['host1']) can override such lists set on the command-line, but only if you’re not careful (or want them to.)
- Globally specified host lists set on the command-line (--hosts=host1) will initialize the env variables, but that’s it.