defrost 0.4.0

PipFreeze

PipFreeze takes a pip freeze output as input and builds packages internally.

>>> from defrost import PipFreeze

>>> pip_freeze_output = """\
foo==1.2.3
bar==2.0
"""

>>> pip_freeze = PipFreeze(pip_freeze_output)
>>> len(pip_freeze)
2

>>> list(pip_freeze)
[Package(foo==1.2.3), Package(bar==2.0)]

# test presence of package foo that is less or equal to v2.0
>>> 'foo<=2.0' in pip_freeze
True

# test presence of any version of package zoo
>>> 'zoo' in pip_freeze
False

# test can also be done with a Package instance
>>> Package('foo==0.1') in pip_freeze
False

# ... or with a Requirement
>>> Requirement('bar>=2.0') in pip_freeze
True

Package deprecation

You can mark packages as deprecated by loading the YAML requirements file and passing the result of it to PipFreeze.load_requirements(). Packages present in PipFreeze will be marked as deprecated if they don’t satisfy the loaded requirements. You can also provide an optional reason to why a package is deprecated.

>>> pip_freeze = PipFreeze("""\
foobar==0.8
bar==2.0
ordereddict==1.1
""")

>>> import yaml
>>> reqs = yaml.load(open('my-reqs.yaml'))
>>> pip_freeze.load_requirements(reqs)
>>> pip_freeze.deprecated
[Package(foobar==0.8), Package(ordereddict==1.1)]
>>> for package in pip_freeze.deprecated:
...     print("%s: deprecated=%s, deprecated_by=%s, reason=%s" % (
            package, package.deprecated, package.deprecated_by, package.deprecation_reason
        ))
...
Package(foobar==0.8): deprecated=True, deprecated_by=Requirement(foobar>=1.0), reason=foobar pre-1.0 is no longer supported, please upgrade to 1.x
Package(ordereddict==1.1): deprecated=True, deprecated_by=Requirement(ordereddict<0.0), reason=ordereddict is part of Python 2.7 and above. If you are still running Python 2.6, please upgrade!

Package

Packages take an exact package version as input.

>>> from defrost import Package

>>> package = Package('foo==1.2')
>>> package.name
'foo'
>>> package.version
'1.2'

If you don’t pass an exact version in your requirement it will raise a ValueError.

>>> package = Package('foo')
>>> Package('foo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    ...
ValueError: foo does not represent an exact package version; the format should be foo==1.0

You can also manually deprecate packages:

>>> package = Package('foo==1.2')
>>> package.deprecated
False
>>> package.deprecate(reason='because')
>>> package.deprecated
True
>>> package.deprecation_reason
'because'

Requirement

A requirement represents a range of package versions.

>>> from defrost import Requirement

>>> req = Requirement('foo>=1.0,<2.0')
>>> req.name
'foo'
>>> req.specifier
[('>=', '1.0'), ('<', '2.0')]

Requirements play well with packages. Using the Python operator in, you can check if a package satifies a requirement.

>>> req = Requirement('foo>=1.0')
>>> Package('foo==1.0') in req
True
>>> Package('foo==2.0') in req
True
>>> Package('foo==0.1') in req
False