The initenv process of trac-admin requires more than just 'psycopg2' and 'trac'

[wind8702@…]

I figured out the initenv process of trac-admin requires more than just 'psycopg2' and 'trac' to use the postgresql driver, the previous week of last week.

Either it is a bug or the wiki page for database backends is missing an important line (DatabaseBackend).

I somehow figured out how to make it work after some digging: I had to also install TracTags from Python Package Index. otherwise I'd get messages like: TracError: Unsupported database type "postgres"

What I did:

useradd -mrd /var/lib/g9-trac g9-trac
mkdir -p /var/log/g9

apt install -y virtualenv
# virtualenv -p /usr/bin/python3 /var/lib/g9-trac/ve-trac
su - g9-trac
virtualenv -p /usr/bin/python2 /var/lib/g9-trac/ve-trac
source /var/lib/g9-trac/ve-trac/bin/activate

pip install trac
#it's weird the psycopg2 driver worked only after I installed TracTags
pip install psycopg2

trac-admin /var/lib/g9-trac/trac-g9 initenv Gxxxxx9 'postgres://g9-trac:passphrase32!@localhost:5432/trac-g9'

Thank you, Gunwoo Gim

[Jun Omae]

InstallationIssue. Please ask on the mailing list.

[wind8702@…]

I do know how to SOMEHOW install it with the postgresql driver now. I thought I'd love to help the developers fix this issue.

Asking, that's how I figured out how to successfully install/initenv, a guy showed his dockerfile and I tried some of the packages in the recipe to figure out TracTags somehow helps with the utilization of the postgresql driver. I got the help on the irc channel.

Jun, I'd like to ask you if you thought I did something wrong in the failed installation, and trac had no bug.

[Jun Omae]

Well, I get the same error with fresh virtualenv.

$ /usr/bin/virtualenv -p /usr/bin/python2.7 /dev/shm/trac-1.2.2
Running virtualenv with interpreter /usr/bin/python2.7
New python executable in /dev/shm/trac-1.2.2/bin/python2.7
Also creating executable in /dev/shm/trac-1.2.2/bin/python
Installing setuptools, pkg_resources, pip, wheel...done.
$ source /dev/shm/trac-1.2.2/bin/activate
(trac-1.2.2) $ type pip
pip is /dev/shm/trac-1.2.2/bin/pip
(trac-1.2.2) $ pip install trac
Collecting trac
  Using cached https://files.pythonhosted.org/packages/85/67/f1549b34fc405d10d09eb9eb52f71cd6b790328177e33e3993a9a08b22b7/Trac-1.2.2-py2-none-any.whl
Requirement already satisfied: setuptools>=0.6 in /dev/shm/trac-1.2.2/lib/python2.7/site-packages (from trac) (39.2.0)
Collecting Genshi>=0.6 (from trac)
  Using cached https://files.pythonhosted.org/packages/c5/2f/34493b2286561d0ea003c568a6c80343eee3c9975a69964d22ce8501dd3f/Genshi-0.7.tar.gz
Installing collected packages: Genshi, trac
  Running setup.py install for Genshi ... done
Successfully installed Genshi-0.7 trac-1.2.2
(trac-1.2.2) $ pip install psycopg2
Collecting psycopg2
  Downloading https://files.pythonhosted.org/packages/7c/e6/d5161798a5e8900f24216cb730f2c2be5e4758a80d35c8588306831c0c99/psycopg2-2.7.5-cp27-cp27mu-manylinux1_x86_64.whl (2.7MB)
    100% |████████████████████████████████| 2.7MB 155kB/s
Installing collected packages: psycopg2
Successfully installed psycopg2-2.7.5
(trac-1.2.2) $ pip list                                                                                       DEPRECATION: The legacy format has been deprecated and will be removed in the future.
Genshi (0.7)
pip (10.0.1)
pkg-resources (0.0.0)
psycopg2 (2.7.5)
setuptools (39.2.0)
Trac (1.2.2)
wheel (0.31.1)
(trac-1.2.2) $ type trac-admin
trac-admin is /dev/shm/trac-1.2.2/bin/trac-admin
(trac-1.2.2) $ trac-admin /dev/shm/trac-1.2.2-tracenv initenv 'My Project' 'postgres://tracuser:password@localhost:5432/trac?schema=trac_1_2_2'
Creating and Initializing Project
Initenv for '/dev/shm/trac-1.2.2-tracenv' failed.
Failed to create environment.
Unsupported database type "postgres"
Traceback (most recent call last):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/admin/console.py", line 500, in do_initenv
    options=options)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/core.py", line 136, in __call__
    self.__init__(*args, **kwargs)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/env.py", line 300, in __init__
    self.create(options)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/env.py", line 592, in create
    DatabaseManager(self).init_db()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/db/api.py", line 337, in init_db
    connector, args = self.get_connector()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/db/api.py", line 615, in get_connector
    scheme=scheme))
TracError: Unsupported database type "postgres"

I noticed UndefinedEnvironmentName raised when loading trac.db.postgres_backend. The issue is due to ​pip, ​setuptools, ​wheel or ​Trac-1.2.2-py2-none-any.whl file.

(trac-1.2.2) $ cat > /dev/shm/trac-1.2.2/inherit.ini
[logging]
log_type = stderr
(trac-1.2.2) $ trac-admin /dev/shm/trac-1.2.2-tracenv initenv --inherit=/dev/shm/trac-1.2.2/inherit.ini 'My Project' 'postgres://tracuser:password@localhost:5432/trac?schema=trac_1_2_2'
Creating and Initializing Project
15:19:45 Trac[env] INFO: -------------------------------- environment startup [Trac 1.2.2] --------------------------------
...
15:19:45 Trac[loader] DEBUG: Loading plugin "trac.db.postgres" from "/dev/shm/trac-1.2.2/lib/python2.7/site-packages"
15:19:45 Trac[loader] ERROR: Skipping "trac.db.postgres = trac.db.postgres_backend [postgresql]":
Traceback (most recent call last):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/trac/loader.py", line 68, in _load_eggs
    entry.load(require=True)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2228, in load
    self.require(*args, **kwargs)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2245, in require
    items = working_set.resolve(reqs, env, installer)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 808, in resolve
    if not req_extras.markers_pass(req):
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 993, in markers_pass
    return not req.marker or any(extra_evals) or req.marker.evaluate()
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 278, in evaluate
    return _evaluate_markers(self._markers, current_environment)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 203, in _evaluate_markers
    lhs_value = _get_env(environment, lhs.value)
  File "/dev/shm/trac-1.2.2/local/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/markers.py", line 185, in _get_env
    "{0!r} does not exist in evaluation environment.".format(name)
UndefinedEnvironmentName: 'extra' does not exist in evaluation environment.
...

Work around is to reinstall Trac using tarball.

$ pip uninstall -y Trac
$ pip install https://download.edgewall.org/trac/Trac-1.2.2.tar.gz
$ trac-admin /dev/shm/trac-1.2.2-tracenv initenv --inherit=/dev/shm/trac-1.2.2/inherit.ini 'My Project' 'postgres://tracuser:password@localhost:5432/trac?schema=trac_1_2_2'
...

The latest documentation can also always be found on the project
website:

  http://trac.edgewall.org/

Congratulations!

[Jun Omae]

Another work around is to downgrade to setuptools 39.1.0.

$ pip install setuptools==39.1.0

[Jun Omae]

Filed in ​https://github.com/pypa/setuptools/issues/1411.

setuptools 40.0.0 is released but the issue is not fixed.