z3c.recipe.usercrontab 0.6

Entry handling

A user crontab manager manages a user’s crontab for one specific buildout part. The part ends up in the identifier. We’ll use ‘test’ here.

>>> c = UserCrontabManager(identifier='test')

In these tests, we can fake a crontab by filling the list of cron entries manually:

>>> c.crontab = ['@reboot echo "hello world"']
>>> print c # Handy shortcut
@reboot echo "hello world"

Now, we’re adding an entry to it using the official way. The entry is surrounded by markers:

>>> c.add_entry('@reboot echo "I just got added"')
>>> print c
@reboot echo "hello world"
<BLANKLINE>
# Generated by test
@reboot echo "I just got added"
# END test
<BLANKLINE>

Removing entries also works. As long as the “Generated by” markers are present, it doesn’t matter which entry you remove: everything surrounded by the markers is zapped:

>>> c.del_entry('bla bla') == 1
True
>>> print c
@reboot echo "hello world"

Pre-0.6, a WARNING environment variable was used. An entry (which content matters now!) is found there:

>>> c.crontab = ['@reboot echo "hello world"',
...              'WARNING="Everything below is added by bla bla',
...              '@reboot echo "old entry 1"',
...              '@reboot echo "old entry 2"']
>>> print c
@reboot echo "hello world"
WARNING="Everything below is added by bla bla
@reboot echo "old entry 1"
@reboot echo "old entry 2"
>>> c.del_entry('@reboot echo "old entry 1"')
1
>>> print c
@reboot echo "hello world"
WARNING="Everything below is added by bla bla
@reboot echo "old entry 2"

Removing the last remaining entry under WARNING also removes the WARNING:

>>> c.del_entry('@reboot echo "old entry 2"')
1
>>> print c
@reboot echo "hello world"

Briefly in the 0.5 version, a ‘BUILDOUT’ environment variable was used for grouping items per buildout. Now for some up/downgrade testing. 0.5.1 removes the environment variable again. We’ll add an entry with such a (now deprecated) “grouping environment variable”. First the start situation:

>>> c.crontab=[
...     'WARNING="Everything below is added by bla bla',
...     'BUILDOUT=my/buildout',
...     '@reboot echo nothing happens']
>>> print c
WARNING="Everything below is added by bla bla
BUILDOUT=my/buildout
@reboot echo nothing happens

Doing anything (adding/removing) zaps BUILDOUT statement:

>>> c.del_entry('nonexisting')
0
>>> print c
WARNING="Everything below is added by bla bla
@reboot echo nothing happens

And just to make sure, deleting that entry empties out the whole file:

>>> c.del_entry('@reboot echo nothing happens')
1
>>> print c
<BLANKLINE>

Read/write crontab methods

Next, test the read_crontab and write_crontab methods; we’ll use cat and a temporary file to not modifiy the crontab of the user running these tests:

>>> import tempfile
>>> t = tempfile.NamedTemporaryFile('w')
>>> crontestfile = t.name
>>> t.write("#dummy\n")

>>> c = UserCrontabManager(readcrontab="cat %s" % crontestfile,
...                        writecrontab="cat >%s" % crontestfile,
...                        identifier='test')
>>> c.read_crontab()
>>> a = repr(c)
>>> c.add_entry('# improbable entry')
>>> c.write_crontab()
>>> c.read_crontab()
>>> b =repr(c)
>>> a == b
False

Now, delete this entry again and make sure the old crontab is restored:

>>> c.del_entry('# improbable entry') == 1
True
>>> c.write_crontab()
>>> c.read_crontab()
>>> b = repr(c)
>>> a == b
True

Buildout recipe usage

Do the buildout shuffle:

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = foo
...
... [foo]
... recipe = z3c.recipe.usercrontab
... times = # @reboot
... command = echo nothing happens
... readcrontab = cat %(crontest)s
... writecrontab = cat >%(crontest)s
... ''' % ( { 'crontest': crontestfile } ))

>>> import os
>>> print 'start', system(buildout)
start...
Installing foo.
<BLANKLINE>

Check that it really was added to the crontab:

>>> c.read_crontab()
>>> b = repr(c)
>>> a == b
False

>>> '# @reboot\techo nothing happens' in c.crontab
True
>>> print c
<BLANKLINE>
# Generated by /sample-buildout [foo]
# @reboot   echo nothing happens
# END /sample-buildout [foo]
<BLANKLINE>

Uninstall the recipe:

>>> write('buildout.cfg',
... '''
... [buildout]
... parts =
... ''' % ( { 'crontest': crontestfile } ))
>>> print 'start', system(buildout)
start...
Uninstalling foo.
Running uninstall recipe.
<BLANKLINE>

And check that its entry was removed (i.e., the contents of the crontab are the same as when this test was started; in any case, the teardown from the testrunner makes sure the old situation is restored):

>>> c.read_crontab()
>>> b = repr(c)
>>> a == b
True

A second part installs fine:

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = foo bar
...
... [foo]
... recipe = z3c.recipe.usercrontab
... times = # @reboot
... command = echo nothing happens
... readcrontab = cat %(crontest)s
... writecrontab = cat >%(crontest)s
...
... [bar]
... recipe = z3c.recipe.usercrontab
... times = # @reboot
... command = echo something happens
... readcrontab = cat %(crontest)s
... writecrontab = cat >%(crontest)s
... ''' % ( { 'crontest': crontestfile } ))
>>> print 'start', system(buildout)
start...
Installing foo.
Installing bar.
<BLANKLINE>
>>> c.read_crontab()
>>> print c
<BLANKLINE>
# Generated by /sample-buildout [foo]
# @reboot   echo nothing happens
# END /sample-buildout [foo]
<BLANKLINE>
<BLANKLINE>
# Generated by /sample-buildout [bar]
# @reboot   echo something happens
# END /sample-buildout [bar]
<BLANKLINE>

Uninstalling also works fine

>>> write('buildout.cfg',
... '''
... [buildout]
... parts =
... ''' % ( { 'crontest': crontestfile } ))
>>> print 'start', system(buildout)
start...
Uninstalling bar.
Running uninstall recipe.
Uninstalling foo.
Running uninstall recipe.
<BLANKLINE>

Safety valves

If the section has been removed, nothing can be found by the uninstall. You get warnings that way:

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = foo
...
... [foo]
... recipe = z3c.recipe.usercrontab
... times = # @reboot
... command = echo nothing happens
... readcrontab = cat %(crontest)s
... writecrontab = cat >%(crontest)s
... ''' % ( { 'crontest': crontestfile } ))

>>> import os
>>> print 'start', system(buildout)
start...
Installing foo.
<BLANKLINE>
>>> c.crontab = []
>>> c.write_crontab()
>>> write('buildout.cfg',
... '''
... [buildout]
... parts =
... ''' % ( { 'crontest': crontestfile } ))
>>> print 'start', system(buildout)
start...
Uninstalling foo.
Running uninstall recipe.
foo: WARNING: Did not find a crontab-entry during uninstall; please check manually if everything was removed correctly
<BLANKLINE>

Another test: pre-0.6 config simulation:

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = foo
...
... [foo]
... recipe = z3c.recipe.usercrontab
... times = # @reboot
... command = echo nothing happens
... readcrontab = cat %(crontest)s
... writecrontab = cat >%(crontest)s
... ''' % ( { 'crontest': crontestfile } ))

>>> import os
>>> print 'start', system(buildout)
start...
Installing foo.
<BLANKLINE>
>>> c.crontab = ['WARNING="Everything below is added by bla bla"',
...              'BUILDOUT=/somewhere/out/there',
...              '# @reboot\techo nothing happens']
>>> c.write_crontab()
>>> write('buildout.cfg',
... '''
... [buildout]
... parts =
... ''' % ( { 'crontest': crontestfile } ))
>>> print 'start', system(buildout)
start...
Uninstalling foo.
Running uninstall recipe.
<BLANKLINE>
>>> c.read_crontab()
>>> print c
<BLANKLINE>