How to use the pip.log.logger function in pip

except ValueError:
            logger.warn("Unsupported hash name %s for package %s" % (link.hash_name, link))
    try:
        total_length = int(resp.headers['content-length'])
    except (ValueError, KeyError, TypeError):
        total_length = 0
    downloaded = 0
    show_progress = total_length > 40 * 1000 or not total_length
    show_url = link.show_url
    try:
        if show_progress:
            ## FIXME: the URL can get really long in this message:
            if total_length:
                logger.start_progress('Downloading %s (%s): ' % (show_url, format_size(total_length)))
            else:
                logger.start_progress('Downloading %s (unknown size): ' % show_url)
        else:
            logger.notify('Downloading %s' % show_url)
        logger.info('Downloading from URL %s' % link)

        def resp_read(chunk_size):
            try:
                # Special case for urllib3.
                try:
                    for chunk in resp.raw.stream(
                            chunk_size, decode_content=False):
                        yield chunk
                except IncompleteRead as e:
                    raise ChunkedEncodingError(e)
            except AttributeError:
                # Standard file-like object.
                while True:

    @classmethod
    def from_line(cls, name, comes_from=None):
        """Creates an InstallRequirement from a name, which might be a
        requirement, filename, or URL.
        """
        url = None
        name = name.strip()
        req = name
        if is_url(name):
            url = name
            ## FIXME: I think getting the requirement here is a bad idea:
            #req = get_requirement_from_url(url)
            req = None
        elif is_filename(name):
            if not os.path.exists(name):
                logger.warn('Requirement %r looks like a filename, but the file does not exist'
                            % name)
            url = filename_to_url(name)
            #req = get_requirement_from_url(url)
            req = None
        return cls(req, comes_from, url=url)

content = zip.read(name)
                    dest = os.path.join(package_path, name)
                    if not os.path.exists(os.path.dirname(dest)):
                        os.makedirs(os.path.dirname(dest))
                    if not content and dest.endswith(os.path.sep):
                        if not os.path.exists(dest):
                            os.makedirs(dest)
                    else:
                        f = open(dest, 'wb')
                        f.write(content)
                        f.close()
                else:
                    to_save.append((name, zip.read(name)))
            zip.close()
            if not to_save:
                logger.info('Removing now-empty zip file %s' % display_path(zip_filename))
                os.unlink(zip_filename)
                self.remove_filename_from_pth(zip_filename)
            else:
                logger.info('Removing entries in %s/ from zip file %s' % (module_name, display_path(zip_filename)))
                zip = zipfile.ZipFile(zip_filename, 'w')
                for name, content in to_save:
                    zip.writestr(name, content)
                zip.close()
        finally:
            logger.indent -= 2

if self.add_requirement(subreq):
                                    reqs.append(subreq)
                    if not self.has_requirement(req_to_install.name):
                        #'unnamed' requirements will get added here
                        self.add_requirement(req_to_install)
                    if self.is_download or req_to_install._temp_build_dir is not None:
                        self.reqs_to_cleanup.append(req_to_install)
                else:
                    self.reqs_to_cleanup.append(req_to_install)

                if install:
                    self.successfully_downloaded.append(req_to_install)
                    if bundle and (req_to_install.url and req_to_install.url.startswith('file:///')):
                        self.copy_to_build_dir(req_to_install)
            finally:
                logger.indent -= 2

except ImportError:
            raise CommandError(
                "'pip wheel' requires setuptools >= 0.8 for dist-info support."
                " To fix this, run: pip install --upgrade setuptools"
            )
        else:
            if not hasattr(pkg_resources, 'DistInfoDistribution'):
                raise CommandError(
                    "'pip wheel' requires setuptools >= 0.8 for dist-info "
                    "support. To fix this, run: pip install --upgrade "
                    "setuptools"
                )

        index_urls = [options.index_url] + options.extra_index_urls
        if options.no_index:
            logger.notify('Ignoring indexes: %s' % ','.join(index_urls))
            index_urls = []

        if options.use_mirrors:
            logger.deprecated("1.7",
                        "--use-mirrors has been deprecated and will be removed"
                        " in the future. Explicit uses of --index-url and/or "
                        "--extra-index-url is suggested.")

        if options.mirrors:
            logger.deprecated("1.7",
                        "--mirrors has been deprecated and will be removed in "
                        " the future. Explicit uses of --index-url and/or "
                        "--extra-index-url is suggested.")
            index_urls += options.mirrors

        session = self._build_session(options)

def __init__(self, src_dir, requirements, successfully_downloaded):
        self.src_dir = src_dir
        self.comparison_cache = ({}, {})  # two maps, one does a->b, the other one does b->a
        self.pre_installed = {}  # maps name -> PackageData
        self.repo_up_to_date = {}  # maps local git clone path -> boolean
        self.requirements = requirements
        self.successfully_downloaded = successfully_downloaded
        try:
            self.load_installed_distributions()
        except Exception, e:
            logger.notify("Exception loading installed distributions " + str(e))
            raise
        self.prefer_pinned_revision = False

def get_info(self, location):
        """Returns (url, revision), where both are strings"""
        assert not location.rstrip('/').endswith(self.dirname), 'Bad directory: %s' % location
        output = call_subprocess(
            ['svn', 'info', location], show_stdout=False, extra_environ={'LANG': 'C'})
        match = _svn_url_re.search(output)
        if not match:
            logger.warn('Cannot determine URL of svn checkout %s' % display_path(location))
            logger.info('Output that cannot be parsed: \n%s' % output)
            return None, None
        url = match.group(1).strip()
        match = _svn_revision_re.search(output)
        if not match:
            logger.warn('Cannot determine revision of svn checkout %s' % display_path(location))
            logger.info('Output that cannot be parsed: \n%s' % output)
            return url, None
        return url, match.group(1)

#unpack and constructs req set
        self.requirement_set.prepare_files(self.finder)

        reqset = self.requirement_set.requirements.values()

        buildset = [req for req in reqset if not req.is_wheel]

        if not buildset:
            return

        #build the wheels
        logger.notify(
            'Building wheels for collected packages: %s' %
            ','.join([req.name for req in buildset])
        )
        logger.indent += 2
        build_success, build_failure = [], []
        for req in buildset:
            if self._build_one(req):
                build_success.append(req)
            else:
                build_failure.append(req)
        logger.indent -= 2

        #notify sucess/failure
        if build_success:
            logger.notify('Successfully built %s' % ' '.join([req.name for req in build_success]))
        if build_failure:
            logger.notify('Failed to build %s' % ' '.join([req.name for req in build_failure]))

if cache is not None:
                                cache.set_is_archive(url)
                            return None
            logger.debug('Getting page %s' % url)
            resp = urllib2.urlopen(url)
            real_url = resp.geturl()
            headers = resp.info()
            inst = cls(resp.read(), real_url, headers)
        except (urllib2.HTTPError, urllib2.URLError, socket.timeout, socket.error), e:
            desc = str(e)
            if isinstance(e, socket.timeout):
                log_meth = logger.info
                level =1
                desc = 'timed out'
            elif isinstance(e, urllib2.URLError):
                log_meth = logger.info
                if hasattr(e, 'reason') and isinstance(e.reason, socket.timeout):
                    desc = 'timed out'
                    level = 1
                else:
                    level = 2
            elif isinstance(e, urllib2.HTTPError) and e.code == 404:
                ## FIXME: notify?
                log_meth = logger.info
                level = 2
            else:
                log_meth = logger.info
                level = 1
            log_meth('Could not fetch URL %s: %s' % (link, desc))
            log_meth('Will skip URL %s when looking for download links for %s' % (link.url, req))
            if cache is not None:
                cache.add_page_failure(url, level)

def print_results(hits, name_column_width=25, terminal_width=None):
    installed_packages = [p.project_name for p in pkg_resources.working_set]
    for hit in hits:
        name = hit['name']
        summary = hit['summary'] or ''
        if terminal_width is not None:
            # wrap and indent summary to fit terminal
            summary = textwrap.wrap(summary, terminal_width - name_column_width - 5)
            summary = ('\n' + ' ' * (name_column_width + 3)).join(summary)
        line = '%s - %s' % (name.ljust(name_column_width), summary)
        try:
            logger.notify(line)
            if name in installed_packages:
                dist = pkg_resources.get_distribution(name)
                logger.indent += 2
                try:
                    latest = highest_version(hit['versions'])
                    if dist.version == latest:
                        logger.notify('INSTALLED: %s (latest)' % dist.version)
                    else:
                        logger.notify('INSTALLED: %s' % dist.version)
                        logger.notify('LATEST:    %s' % latest)
                finally:
                    logger.indent -= 2
        except UnicodeEncodeError:
            pass