annotate mercurial/hgweb/hgwebdir_mod.py @ 35854:ff2370a70fe8 stable

hgweb: garbage collect on every request

There appears to be a cycle in localrepository or hgweb that
is preventing repositories from being garbage collected when
hgwebdir dispatches to hgweb. Every request creates a new
repository instance and then leaks that object and other referenced
objects. A periodic GC to find cycles will eventually collect the
old repositories. But these don't run reliably and rapid requests
to hgwebdir can result in rapidly increasing memory consumption.

With the Firefox repository, repeated requests to raw-file URLs
leak ~100 MB per hgwebdir request (most of this appears to be
cached manifest data structures). WSGI processes quickly grow
to >1 GB RSS.

Breaking the cycles in localrepository is going to be a bit of
work.

Because we know that hgwebdir leaks localrepository instances, let's
put a band aid on the problem in the form of an explicit gc.collect()
on every hgwebdir request.

As the inline comment states, ideally we'd do this in a finally
block for the current request iff it dispatches to hgweb. But
_runwsgi() returns an explicit value. We need the finally to run
after generator exhaustion. So we'd need to refactor _runwsgi()
to "yield" instead of "return." That's too much change for a patch
to stable. So we implement this hack one function above and run
it on every request.

The performance impact of this change should be minimal. Any
impact should be offset by benefits from not having hgwebdir
processes leak memory.

# hgweb/hgwebdir_mod.py - Web interface for a directory of repositories.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import gc
import os
import re
import time

from ..i18n import _

from .common import (
    ErrorResponse,
    HTTP_NOT_FOUND,
    HTTP_OK,
    HTTP_SERVER_ERROR,
    cspvalues,
    get_contact,
    get_mtime,
    ismember,
    paritygen,
    staticfile,
)
from .request import wsgirequest

from .. import (
    configitems,
    encoding,
    error,
    hg,
    profiling,
    pycompat,
    scmutil,
    templater,
    ui as uimod,
    util,
)

from . import (
    hgweb_mod,
    webutil,
    wsgicgi,
)

def cleannames(items):
    return [(util.pconvert(name).strip('/'), path) for name, path in items]

def findrepos(paths):
    repos = []
    for prefix, root in cleannames(paths):
        roothead, roottail = os.path.split(root)
        # "foo = /bar/*" or "foo = /bar/**" lets every repo /bar/N in or below
        # /bar/ be served as as foo/N .
        # '*' will not search inside dirs with .hg (except .hg/patches),
        # '**' will search inside dirs with .hg (and thus also find subrepos).
        try:
            recurse = {'*': False, '**': True}[roottail]
        except KeyError:
            repos.append((prefix, root))
            continue
        roothead = os.path.normpath(os.path.abspath(roothead))
        paths = scmutil.walkrepos(roothead, followsym=True, recurse=recurse)
        repos.extend(urlrepos(prefix, roothead, paths))
    return repos

def urlrepos(prefix, roothead, paths):
    """yield url paths and filesystem paths from a list of repo paths

    >>> conv = lambda seq: [(v, util.pconvert(p)) for v,p in seq]
    >>> conv(urlrepos(b'hg', b'/opt', [b'/opt/r', b'/opt/r/r', b'/opt']))
    [('hg/r', '/opt/r'), ('hg/r/r', '/opt/r/r'), ('hg', '/opt')]
    >>> conv(urlrepos(b'', b'/opt', [b'/opt/r', b'/opt/r/r', b'/opt']))
    [('r', '/opt/r'), ('r/r', '/opt/r/r'), ('', '/opt')]
    """
    for path in paths:
        path = os.path.normpath(path)
        yield (prefix + '/' +
               util.pconvert(path[len(roothead):]).lstrip('/')).strip('/'), path

def geturlcgivars(baseurl, port):
    """
    Extract CGI variables from baseurl

    >>> geturlcgivars(b"http://host.org/base", b"80")
    ('host.org', '80', '/base')
    >>> geturlcgivars(b"http://host.org:8000/base", b"80")
    ('host.org', '8000', '/base')
    >>> geturlcgivars(b'/base', 8000)
    ('', '8000', '/base')
    >>> geturlcgivars(b"base", b'8000')
    ('', '8000', '/base')
    >>> geturlcgivars(b"http://host", b'8000')
    ('host', '8000', '/')
    >>> geturlcgivars(b"http://host/", b'8000')
    ('host', '8000', '/')
    """
    u = util.url(baseurl)
    name = u.host or ''
    if u.port:
        port = u.port
    path = u.path or ""
    if not path.startswith('/'):
        path = '/' + path

    return name, pycompat.bytestr(port), path

class hgwebdir(object):
    """HTTP server for multiple repositories.

    Given a configuration, different repositories will be served depending
    on the request path.

    Instances are typically used as WSGI applications.
    """
    def __init__(self, conf, baseui=None):
        self.conf = conf
        self.baseui = baseui
        self.ui = None
        self.lastrefresh = 0
        self.motd = None
        self.refresh()

    def refresh(self):
        if self.ui:
            refreshinterval = self.ui.configint('web', 'refreshinterval')
        else:
            item = configitems.coreitems['web']['refreshinterval']
            refreshinterval = item.default

        # refreshinterval <= 0 means to always refresh.
        if (refreshinterval > 0 and
            self.lastrefresh + refreshinterval > time.time()):
            return

        if self.baseui:
            u = self.baseui.copy()
        else:
            u = uimod.ui.load()
            u.setconfig('ui', 'report_untrusted', 'off', 'hgwebdir')
            u.setconfig('ui', 'nontty', 'true', 'hgwebdir')
            # displaying bundling progress bar while serving feels wrong and may
            # break some wsgi implementations.
            u.setconfig('progress', 'disable', 'true', 'hgweb')

        if not isinstance(self.conf, (dict, list, tuple)):
            map = {'paths': 'hgweb-paths'}
            if not os.path.exists(self.conf):
                raise error.Abort(_('config file %s not found!') % self.conf)
            u.readconfig(self.conf, remap=map, trust=True)
            paths = []
            for name, ignored in u.configitems('hgweb-paths'):
                for path in u.configlist('hgweb-paths', name):
                    paths.append((name, path))
        elif isinstance(self.conf, (list, tuple)):
            paths = self.conf
        elif isinstance(self.conf, dict):
            paths = self.conf.items()

        repos = findrepos(paths)
        for prefix, root in u.configitems('collections'):
            prefix = util.pconvert(prefix)
            for path in scmutil.walkrepos(root, followsym=True):
                repo = os.path.normpath(path)
                name = util.pconvert(repo)
                if name.startswith(prefix):
                    name = name[len(prefix):]
                repos.append((name.lstrip('/'), repo))

        self.repos = repos
        self.ui = u
        encoding.encoding = self.ui.config('web', 'encoding')
        self.style = self.ui.config('web', 'style')
        self.templatepath = self.ui.config('web', 'templates', untrusted=False)
        self.stripecount = self.ui.config('web', 'stripes')
        if self.stripecount:
            self.stripecount = int(self.stripecount)
        self._baseurl = self.ui.config('web', 'baseurl')
        prefix = self.ui.config('web', 'prefix')
        if prefix.startswith('/'):
            prefix = prefix[1:]
        if prefix.endswith('/'):
            prefix = prefix[:-1]
        self.prefix = prefix
        self.lastrefresh = time.time()

    def run(self):
        if not encoding.environ.get('GATEWAY_INTERFACE',
                                    '').startswith("CGI/1."):
            raise RuntimeError("This function is only intended to be "
                               "called while running as a CGI script.")
        wsgicgi.launch(self)

    def __call__(self, env, respond):
        req = wsgirequest(env, respond)
        return self.run_wsgi(req)

    def read_allowed(self, ui, req):
        """Check allow_read and deny_read config options of a repo's ui object
        to determine user permissions.  By default, with neither option set (or
        both empty), allow all users to read the repo.  There are two ways a
        user can be denied read access:  (1) deny_read is not empty, and the
        user is unauthenticated or deny_read contains user (or *), and (2)
        allow_read is not empty and the user is not in allow_read.  Return True
        if user is allowed to read the repo, else return False."""

        user = req.env.get('REMOTE_USER')

        deny_read = ui.configlist('web', 'deny_read', untrusted=True)
        if deny_read and (not user or ismember(ui, user, deny_read)):
            return False

        allow_read = ui.configlist('web', 'allow_read', untrusted=True)
        # by default, allow reading if no allow_read option has been set
        if (not allow_read) or ismember(ui, user, allow_read):
            return True

        return False

    def run_wsgi(self, req):
        profile = self.ui.configbool('profiling', 'enabled')
        with profiling.profile(self.ui, enabled=profile):
            try:
                for r in self._runwsgi(req):
                    yield r
            finally:
                # There are known cycles in localrepository that prevent
                # those objects (and tons of held references) from being
                # collected through normal refcounting. We mitigate those
                # leaks by performing an explicit GC on every request.
                # TODO remove this once leaks are fixed.
                # TODO only run this on requests that create localrepository
                # instances instead of every request.
                gc.collect()

    def _runwsgi(self, req):
        try:
            self.refresh()

            csp, nonce = cspvalues(self.ui)
            if csp:
                req.headers.append(('Content-Security-Policy', csp))

            virtual = req.env.get("PATH_INFO", "").strip('/')
            tmpl = self.templater(req, nonce)
            ctype = tmpl('mimetype', encoding=encoding.encoding)
            ctype = templater.stringify(ctype)

            # a static file
            if virtual.startswith('static/') or 'static' in req.form:
                if virtual.startswith('static/'):
                    fname = virtual[7:]
                else:
                    fname = req.form['static'][0]
                static = self.ui.config("web", "static", None,
                                        untrusted=False)
                if not static:
                    tp = self.templatepath or templater.templatepaths()
                    if isinstance(tp, str):
                        tp = [tp]
                    static = [os.path.join(p, 'static') for p in tp]
                staticfile(static, fname, req)
                return []

            # top-level index

            repos = dict(self.repos)

            if (not virtual or virtual == 'index') and virtual not in repos:
                req.respond(HTTP_OK, ctype)
                return self.makeindex(req, tmpl)

            # nested indexes and hgwebs

            if virtual.endswith('/index') and virtual not in repos:
                subdir = virtual[:-len('index')]
                if any(r.startswith(subdir) for r in repos):
                    req.respond(HTTP_OK, ctype)
                    return self.makeindex(req, tmpl, subdir)

            def _virtualdirs():
                # Check the full virtual path, each parent, and the root ('')
                if virtual != '':
                    yield virtual

                    for p in util.finddirs(virtual):
                        yield p

                yield ''

            for virtualrepo in _virtualdirs():
                real = repos.get(virtualrepo)
                if real:
                    req.env['REPO_NAME'] = virtualrepo
                    try:
                        # ensure caller gets private copy of ui
                        repo = hg.repository(self.ui.copy(), real)
                        return hgweb_mod.hgweb(repo).run_wsgi(req)
                    except IOError as inst:
                        msg = encoding.strtolocal(inst.strerror)
                        raise ErrorResponse(HTTP_SERVER_ERROR, msg)
                    except error.RepoError as inst:
                        raise ErrorResponse(HTTP_SERVER_ERROR, bytes(inst))

            # browse subdirectories
            subdir = virtual + '/'
            if [r for r in repos if r.startswith(subdir)]:
                req.respond(HTTP_OK, ctype)
                return self.makeindex(req, tmpl, subdir)

            # prefixes not found
            req.respond(HTTP_NOT_FOUND, ctype)
            return tmpl("notfound", repo=virtual)

        except ErrorResponse as err:
            req.respond(err, ctype)
            return tmpl('error', error=err.message or '')
        finally:
            tmpl = None

    def makeindex(self, req, tmpl, subdir=""):

        def archivelist(ui, nodeid, url):
            allowed = ui.configlist("web", "allow_archive", untrusted=True)
            archives = []
            for typ, spec in hgweb_mod.archivespecs.iteritems():
                if typ in allowed or ui.configbool("web", "allow" + typ,
                                                    untrusted=True):
                    archives.append({"type": typ, "extension": spec[2],
                                     "node": nodeid, "url": url})
            return archives

        def rawentries(subdir="", **map):

            descend = self.ui.configbool('web', 'descend')
            collapse = self.ui.configbool('web', 'collapse')
            seenrepos = set()
            seendirs = set()
            for name, path in self.repos:

                if not name.startswith(subdir):
                    continue
                name = name[len(subdir):]
                directory = False

                if '/' in name:
                    if not descend:
                        continue

                    nameparts = name.split('/')
                    rootname = nameparts[0]

                    if not collapse:
                        pass
                    elif rootname in seendirs:
                        continue
                    elif rootname in seenrepos:
                        pass
                    else:
                        directory = True
                        name = rootname

                        # redefine the path to refer to the directory
                        discarded = '/'.join(nameparts[1:])

                        # remove name parts plus accompanying slash
                        path = path[:-len(discarded) - 1]

                        try:
                            r = hg.repository(self.ui, path)
                            directory = False
                        except (IOError, error.RepoError):
                            pass

                parts = [name]
                parts.insert(0, '/' + subdir.rstrip('/'))
                if req.env['SCRIPT_NAME']:
                    parts.insert(0, req.env['SCRIPT_NAME'])
                url = re.sub(r'/+', '/', '/'.join(parts) + '/')

                # show either a directory entry or a repository
                if directory:
                    # get the directory's time information
                    try:
                        d = (get_mtime(path), util.makedate()[1])
                    except OSError:
                        continue

                    # add '/' to the name to make it obvious that
                    # the entry is a directory, not a regular repository
                    row = {'contact': "",
                           'contact_sort': "",
                           'name': name + '/',
                           'name_sort': name,
                           'url': url,
                           'description': "",
                           'description_sort': "",
                           'lastchange': d,
                           'lastchange_sort': d[1]-d[0],
                           'archives': [],
                           'isdirectory': True,
                           'labels': [],
                           }

                    seendirs.add(name)
                    yield row
                    continue

                u = self.ui.copy()
                try:
                    u.readconfig(os.path.join(path, '.hg', 'hgrc'))
                except Exception as e:
                    u.warn(_('error reading %s/.hg/hgrc: %s\n') % (path, e))
                    continue
                def get(section, name, default=uimod._unset):
                    return u.config(section, name, default, untrusted=True)

                if u.configbool("web", "hidden", untrusted=True):
                    continue

                if not self.read_allowed(u, req):
                    continue

                # update time with local timezone
                try:
                    r = hg.repository(self.ui, path)
                except IOError:
                    u.warn(_('error accessing repository at %s\n') % path)
                    continue
                except error.RepoError:
                    u.warn(_('error accessing repository at %s\n') % path)
                    continue
                try:
                    d = (get_mtime(r.spath), util.makedate()[1])
                except OSError:
                    continue

                contact = get_contact(get)
                description = get("web", "description")
                seenrepos.add(name)
                name = get("web", "name", name)
                row = {'contact': contact or "unknown",
                       'contact_sort': contact.upper() or "unknown",
                       'name': name,
                       'name_sort': name,
                       'url': url,
                       'description': description or "unknown",
                       'description_sort': description.upper() or "unknown",
                       'lastchange': d,
                       'lastchange_sort': d[1]-d[0],
                       'archives': archivelist(u, "tip", url),
                       'isdirectory': None,
                       'labels': u.configlist('web', 'labels', untrusted=True),
                       }

                yield row

        sortdefault = None, False
        def entries(sortcolumn="", descending=False, subdir="", **map):
            rows = rawentries(subdir=subdir, **map)

            if sortcolumn and sortdefault != (sortcolumn, descending):
                sortkey = '%s_sort' % sortcolumn
                rows = sorted(rows, key=lambda x: x[sortkey],
                              reverse=descending)
            for row, parity in zip(rows, paritygen(self.stripecount)):
                row['parity'] = parity
                yield row

        self.refresh()
        sortable = ["name", "description", "contact", "lastchange"]
        sortcolumn, descending = sortdefault
        if 'sort' in req.form:
            sortcolumn = req.form['sort'][0]
            descending = sortcolumn.startswith('-')
            if descending:
                sortcolumn = sortcolumn[1:]
            if sortcolumn not in sortable:
                sortcolumn = ""

        sort = [("sort_%s" % column,
                 "%s%s" % ((not descending and column == sortcolumn)
                            and "-" or "", column))
                for column in sortable]

        self.refresh()
        self.updatereqenv(req.env)

        return tmpl("index", entries=entries, subdir=subdir,
                    pathdef=hgweb_mod.makebreadcrumb('/' + subdir, self.prefix),
                    sortcolumn=sortcolumn, descending=descending,
                    **dict(sort))

    def templater(self, req, nonce):

        def motd(**map):
            if self.motd is not None:
                yield self.motd
            else:
                yield config('web', 'motd')

        def config(section, name, default=uimod._unset, untrusted=True):
            return self.ui.config(section, name, default, untrusted)

        self.updatereqenv(req.env)

        url = req.env.get('SCRIPT_NAME', '')
        if not url.endswith('/'):
            url += '/'

        vars = {}
        styles, (style, mapfile) = hgweb_mod.getstyle(req, config,
                                                      self.templatepath)
        if style == styles[0]:
            vars['style'] = style

        start = r'&' if url[-1] == r'?' else r'?'
        sessionvars = webutil.sessionvars(vars, start)
        logourl = config('web', 'logourl')
        logoimg = config('web', 'logoimg')
        staticurl = config('web', 'staticurl') or url + 'static/'
        if not staticurl.endswith('/'):
            staticurl += '/'

        defaults = {
            "encoding": encoding.encoding,
            "motd": motd,
            "url": url,
            "logourl": logourl,
            "logoimg": logoimg,
            "staticurl": staticurl,
            "sessionvars": sessionvars,
            "style": style,
            "nonce": nonce,
        }
        tmpl = templater.templater.frommapfile(mapfile, defaults=defaults)
        return tmpl

    def updatereqenv(self, env):
        if self._baseurl is not None:
            name, port, path = geturlcgivars(self._baseurl, env['SERVER_PORT'])
            env['SERVER_NAME'] = name
            env['SERVER_PORT'] = port
            env['SCRIPT_NAME'] = path