packages.py

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"""
Determine which packages are being used in the system and their versions

There are a few different types of packages, and their versions are collected in different ways:
1. Run-time libraries (e.g., cfitsio, fftw): we get their version from interrogating the dynamic library
2. Python modules (e.g., afw, numpy; galsim is also in this group even though we only use it through the
   library, because no version information is currently provided through the library): we get their version
   from the __version__ module variable. Note that this means that we're only aware of modules that have
   already been imported.
3. Other packages provide no run-time accessible version information (e.g., astrometry_net): we get their
   version from interrogating the environment. Currently, that means EUPS; if EUPS is replaced or dropped then
   we'll need to consider an alternative means of getting this version information.
4. Local versions of packages (a non-installed EUPS package, selected with "setup -r /path/to/package"): we
   identify these through the environment (EUPS again) and use as a version the path supplemented with the
   git SHA and, if the git repo isn't clean, an MD5 of the diff.

These package versions are collected and stored in a Packages object, which provides useful comparison and
persistence features.

Example usage:

    from lsst.base import Packages
    pkgs = Packages.fromSystem()
    print "Current packages:", pkgs
    old = Packages.read("/path/to/packages.pickle")
    print "Old packages:", old
    print "Missing packages compared to before:", pkgs.missing(old)
    print "Extra packages compared to before:", pkgs.extra(old)
    print "Different packages: ", pkgs.difference(old)
    old.update(pkgs)  # Include any new packages in the old
    old.write("/path/to/packages.pickle")
"""
from future import standard_library
standard_library.install_aliases()
from builtins import object

import os
import sys
import hashlib
import importlib
import subprocess
import pickle as pickle
from collections import Mapping

from .baseLib import getRuntimeVersions

__all__ = ["getVersionFromPythonModule", "getPythonPackages", "getEnvironmentPackages", "Packages"]


# Packages used at build-time (e.g., header-only)
BUILDTIME = set(["boost", "eigen", "tmv"])

# Python modules to attempt to load so we can try to get the version
# We do this because the version only appears to be available from python, but we use the library
PYTHON = set(["galsim"])

# Packages that don't seem to have a mechanism for reporting the runtime version
# We need to guess the version from the environment
ENVIRONMENT = set(["astrometry_net", "astrometry_net_data", "minuit2", "xpa"])


def getVersionFromPythonModule(module):
    """Determine the version of a python module

    Will raise AttributeError if the __version__ attribute is not set.

    We supplement the version with information from the __dependency_versions__
    (a specific variable set by LSST's sconsUtils at build time) only for packages
    that are typically used only at build-time.
    """
    version = module.__version__
    if hasattr(module, "__dependency_versions__"):
        # Add build-time dependencies
        deps = module.__dependency_versions__
        buildtime = BUILDTIME & set(deps.keys())
        if buildtime:
            version += " with " + " ".join("%s=%s" % (pkg, deps[pkg]) for pkg in buildtime)
    return version


def getPythonPackages():
    """Return a dict of imported python packages and their versions

    We wade through sys.modules and attempt to determine the version for each
    module.  Note, therefore, that we can only report on modules that have
    *already* been imported.

    We don't include any module for which we cannot determine a version.
    """
    # Attempt to import libraries that only report their version in python
    for module in PYTHON:
        try:
            importlib.import_module(module)
        except:
            pass  # It's not available, so don't care

    packages = {"python": sys.version}
    # Not iterating with sys.modules.iteritems() because it's not atomic and subject to race conditions
    moduleNames = list(sys.modules.keys())
    for name in moduleNames:
        module = sys.modules[name]
        try:
            ver = getVersionFromPythonModule(module)
        except:
            continue  # Can't get a version from it, don't care

        # Remove "foo.bar.version" in favor of "foo.bar"
        # This prevents duplication when the __init__.py includes "from .version import *"
        found = False
        for ending in (".version", "._version"):
            if name.endswith(ending):
                name = name[:-len(ending)]
                if name in packages:
                    assert ver == packages[name]
                    found = True
            elif name in packages:
                assert ver == packages[name]

        # Use LSST package names instead of python module names
        # This matches the names we get from the environment (i.e., EUPS) so we can clobber these build-time
        # versions if the environment reveals that we're not using the packages as-built.
        if "lsst" in name:
            name = name.replace("lsst.", "").replace(".", "_")

        packages[name] = ver

    return packages


_eups = None  # Singleton Eups object
def getEnvironmentPackages():
    """Provide a dict of products and their versions from the environment

    We use EUPS to determine the version of certain products (those that don't provide
    a means to determine the version any other way) and to check if uninstalled packages
    are being used. We only report the product/version for these packages.
    """
    try:
        from eups import Eups
        from eups.Product import Product
    except:
        from lsst.pex.logging import getDefaultLog
        getDefaultLog().warn("Unable to import eups, so cannot determine package versions from environment")
        return {}

    # Cache eups object since creating it can take a while
    global _eups
    if not _eups:
        _eups = Eups()
    products = _eups.findProducts(tags=["setup"])

    # Get versions for things we can't determine via runtime mechanisms
    # XXX Should we just grab everything we can, rather than just a predetermined set?
    packages = {prod.name: prod.version for prod in products if prod in ENVIRONMENT}

    # The string 'LOCAL:' (the value of Product.LocalVersionPrefix) in the version name indicates uninstalled
    # code, so the version could be different than what's being reported by the runtime environment (because
    # we don't tend to run "scons" every time we update some python file, and even if we did sconsUtils
    # probably doesn't check to see if the repo is clean).
    for prod in products:
        if not prod.version.startswith(Product.LocalVersionPrefix):
            continue
        ver = prod.version

        gitDir = os.path.join(prod.dir, ".git")
        if os.path.exists(gitDir):
            # get the git revision and an indication if the working copy is clean
            revCmd = ["git", "--git-dir=" + gitDir, "--work-tree=" + prod.dir, "rev-parse", "HEAD"]
            diffCmd = ["git", "--no-pager", "--git-dir=" + gitDir, "--work-tree=" + prod.dir, "diff",
                       "--patch"]
            try:
                rev = subprocess.check_output(revCmd).decode().strip()
                diff = subprocess.check_output(diffCmd)
            except:
                ver += "@GIT_ERROR"
            else:
                ver += "@" + rev
                if diff:
                    ver += "+" + hashlib.md5(diff).hexdigest()
        else:
            ver += "@NO_GIT"

        packages[prod.name] = ver
    return packages


class Packages(object):
    """A table of packages and their versions

    Essentially a wrapper around a dict with some conveniences.
    """

    def __init__(self, packages):
        """Constructor

        'packages' should be a mapping {package: version}, such as a dict.
        """
        assert isinstance(packages, Mapping)
        self._packages = packages
        self._names = set(packages.keys())

    @classmethod
    def fromSystem(cls):
        """Construct from the system

        Attempts to determine packages by examining the system (python's sys.modules,
        runtime libraries and EUPS).
        """
        packages = {}
        packages.update(getPythonPackages())
        packages.update(getRuntimeVersions())
        packages.update(getEnvironmentPackages())  # Should be last, to override products with LOCAL versions
        return cls(packages)

    @classmethod
    def read(cls, filename):
        """Read packages from filename"""
        with open(filename, "rb") as ff:
            return pickle.load(ff)

    def write(self, filename):
        """Write packages to file"""
        with open(filename, "wb") as ff:
            pickle.dump(self, ff)

    def __len__(self):
        return len(self._packages)

    def __str__(self):
        ss = "%s({\n" % self.__class__.__name__
        # Sort alphabetically by module name, for convenience in reading
        ss += ",\n".join("%s: %s" % (repr(prod), repr(self._packages[prod])) for
                         prod in sorted(self._names))
        ss += ",\n})"
        return ss

    def __repr__(self):
        return "%s(%s)" % (self.__class__.__name__, repr(self._packages))

    def update(self, other):
        """Update packages using another set of packages

        No check is made to see if we're clobbering anything.
        """
        self._packages.update(other._packages)
        self._names.update(other._names)

    def extra(self, other):
        """Return packages in 'self' but not in 'other'

        These are extra packages in 'self' compared to 'other'.
        """
        return {pkg: self._packages[pkg] for pkg in self._names - other._names}

    def missing(self, other):
        """Return packages in 'other' but not in 'self'

        These are missing packages in 'self' compared to 'other'.
        """
        return {pkg: other._packages[pkg] for pkg in other._names - self._names}

    def difference(self, other):
        """Return packages different between 'self' and 'other'"""
        return {pkg: (self._packages[pkg], other._packages[pkg]) for
                pkg in self._names & other._names if self._packages[pkg] != other._packages[pkg]}