Files @ f734d107296e
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Location: kallithea/scripts/dbmigrate-test

Mads Kiilerich
auth: for default permissions, use existing explicit query result values instead of following dot references in ORM result objects

There has been reports of spurious crashes on resolving references like
.repository from Permissions:

File ".../kallithea/lib/auth.py", line 678, in __wrapper
if self.check_permissions(user):
File ".../kallithea/lib/auth.py", line 718, in check_permissions
return user.has_repository_permission_level(repo_name, self.required_perm)
File ".../kallithea/lib/auth.py", line 450, in has_repository_permission_level
actual_perm = self.permissions['repositories'].get(repo_name)
File ".../kallithea/lib/vcs/utils/lazy.py", line 41, in __get__
value = self._func(obj)
File ".../kallithea/lib/auth.py", line 442, in permissions
return self.__get_perms(user=self, cache=False)
File ".../kallithea/lib/auth.py", line 498, in __get_perms
return compute(user_id, user_is_admin)
File ".../kallithea/lib/auth.py", line 190, in _cached_perms_data
r_k = perm.UserRepoToPerm.repository.repo_name
File ".../sqlalchemy/orm/attributes.py", line 285, in __get__
return self.impl.get(instance_state(instance), dict_)
File ".../sqlalchemy/orm/attributes.py", line 721, in get
value = self.callable_(state, passive)
File ".../sqlalchemy/orm/strategies.py", line 710, in _load_for_state
% (orm_util.state_str(state), self.key)

sqlalchemy.orm.exc.DetachedInstanceError: Parent instance <UserRepoToPerm at ...> is not bound to a Session; lazy load operation of attribute 'repository' cannot proceed (Background on this error at: http://sqlalche.me/e/bhk3)

Permissions are cached between requests: SA result records are stored in in
beaker.cache.sql_cache_short and resued in following requests after the initial
session as been removed. References in Permission objects would usually give
lazy lookup ... but not outside the original session, where we would get an
error like this.

Permissions are indeed implemented/used incorrectly. That might explain a part
of the problem. Even if not fully explaining or fixing this problem, it is
still worth fixing:

Permissions are fetched from the database using Session().query with multiple
class/table names (joined together in way that happens to match the references
specified in the table definitions) - including Repository. The results are
thus "structs" with selected objects. If repositories always were retrieved
using this selected repository, everything would be fine. In some places, this
was what we did.

But in some places, the code happened to do what was more intuitive: just use
.repository and rely on "lazy" resolving. SA was not aware that this one
already was present in the result struct, and would try to fetch it again. Best
case, that could be inefficient. Worst case, it would fail as we see here.

Fix this by only querying from one table but use the "joinedload" option to
also fetch other referenced tables in the same select. (This might
inefficiently return the main record multiple times ... but that was already
the case with the previous approach.)

This change is thus doing multiple things with circular dependencies that can't
be split up in minor parts without taking detours:

The existing repository join like:
.join((Repository, UserGroupRepoToPerm.repository_id == Repository.repo_id))
is thus replaced by:
.options(joinedload(UserGroupRepoToPerm.repository))

Since we only are doing Session.query() on one table, the results will be of
that type instead of "structs" with multiple objects. If only querying for
UserRepoToPerm this means:
- perm.UserRepoToPerm.repository becomes perm.repository
- perm.Permission.permission_name looked at the explicitly queried Permission
in the result struct - instead it should look in the the dereferenced
repository as perm.permission.permission_name
#!/bin/sh -e

if [ $# -lt 2 ] || [ $# -gt 3 ]; then
    cat >&2 <<EOD
usage: $0 CONFIG_FILE FROM_REV [TO_REV]

Runs a database migration from FROM_REV to TO_REV (default: current
working directory parent), using the specified CONFIG_FILE (.ini file).

Test is run using a clean Kallithea install, in a temporary virtual
environment. FROM_REV and (optional) TO_REV should be Mercurial revision
identifiers (e.g. changeset hash or a version number tag). The working
directory is not touched, but the database referenced in the config file
will be (re)created.

Only SQLite is available out of the box; for MySQL or PostgreSQL, set
the EXTRA environment variable to the required package(s), and it'll
be installed in the virtual environment. (E.g. EXTRA=MySQL-python or
EXTRA=psycopg2.)

The temporary directory is not removed, allowing follow-up examination
of the upgrade results. It is, however, created in /tmp by default,
which many Linux distributions automatically clean at regular intervals.
EOD
    exit 1
fi

config_file=$(readlink -f "$1")
from_rev=$2
to_rev=$3
source_repo=$(dirname "$(dirname "$(readlink -f "$0")")")

announce() {
    echo
    echo "$1"
    echo
}

quiet_if_ok() (
    local output
    local st
    set +e
    output=$("$@" < /dev/null 2>&1)
    st=$?
    if [ $st -ne 0 ]; then
        echo "$output" >&2
        echo "Command $@ returned exit status $st." >&2
        exit 1
    fi
)

HG() {
    "${HG:-hg}" --repository "$source_repo" "$@"
}

# If upgrading to "current revision", warn if working directory is dirty.
if [ ! "$to_rev" ] && [ "$(HG status -mard)" ]; then
    announce "Warning: Uncommitted changes in working directory will be ignored!"
fi

from_rev_hash=$(HG id --id --rev "${from_rev:-.}")
to_rev_hash=$(HG id --id --rev "${to_rev:-.}")
temp=$(readlink -f "$(mktemp --tmpdir -d 'dbmigrate-test.XXXXXX')")

cat <<EOD
Config file:    $config_file
EOD
sed -n -e 's/^sqlalchemy\.url *= */Database URL:   /p' "$config_file"
cat <<EOD
Working dir:    $temp
Repository:     $source_repo
Upgrade from:   $from_rev_hash (${from_rev:-current})
Upgrade to:     $to_rev_hash (${to_rev:-current})
Extra packages: ${EXTRA:-(none)}
EOD

mkdir "$temp/repos" # empty

# Enable caching for old pip versions (this will cache the pip upgrade)
# Newer pip versions cache automatically, and don't use this variable.
if [ ! "$PIP_DOWNLOAD_CACHE" ]; then
    export PIP_DOWNLOAD_CACHE=$HOME/.cache/pip/legacy
fi

install_kallithea() {
    local prefix=$1
    local rev=$2

    announce "Installing Kallithea $rev in $prefix..."

    "${VIRTUALENV:-virtualenv}" --quiet "$prefix-env"
    HG archive --rev "$rev" "$prefix"

    (
        cd "$prefix"
        . "$prefix-env/bin/activate"
        pip install --quiet --upgrade pip setuptools mercurial $EXTRA
        pip install --quiet -e .
    )
}

install_kallithea "$temp/from" "$from_rev_hash"
(
    cd "$temp/from"
    . "$temp/from-env/bin/activate"
    announce "Initializing database..."
    quiet_if_ok kallithea-cli db-create -c "$config_file" --repos="$temp/repos" --user=doe --email=doe@example.com --password=123456 --no-public-access --force-yes
    alembic -c "$config_file" current -v
)

install_kallithea "$temp/to" "$to_rev_hash"
(
    cd "$temp/to"
    . "$temp/to-env/bin/activate"

    announce "Commencing database upgrade from shown Alembic revision to head..."
    alembic -c "$config_file" current -v
    alembic -c "$config_file" upgrade head
    announce "Upgrade complete, now at the shown Alembic revision:"
    alembic -c "$config_file" current -v
)