Heroku push di django app ottiene "Nessun modulo chiamato psycopg2.extensions"

Question

Sto provando a spingere un'applicazione django su heroku e ricevendo un errore che non ho visto da nessuna parte nei forum heroku o stackoverflow. Sto usando Postgres.

Non sono sicuro di dove procedere; Non vedo nulla in nessuno dei documenti che dice cosa è sbagliato. L'errore principale è:

ImportError: Nessun modulo denominato psycopg2.extensions

... ma la configurazione di Heroku è quella che è l'impostazione che, come il motore, non so come ottenere da essa .

La mia conversazione con Heroku per assicurarsi che conosce Postgres

$ heroku addons:add heroku-postgresql:dev 
Adding heroku-postgresql:dev on morning-crag-1585... done, v24 (free) 
Attached as HEROKU_POSTGRESQL_OLIVE_URL 
Database has been created and is available 
! This database is empty. If upgrading, you can transfer 
! data from another database with pgbackups:restore. 
. 
Use `heroku addons:docs heroku-postgresql:dev` to view documentation. 
$ heroku pg:wait 
$ heroku config | grep HEROKU_POSTGRESQL 
HEROKU_POSTGRESQL_OLIVE_URL: postgres://<blah-blah-blah>@ec2-<ip-address>.compute-1.amazonaws.com:5432/<blah-blah> 
$ heroku pg:promote HEROKU_POSTGRESQL_OLIVE_URL 
Promoting HEROKU_POSTGRESQL_OLIVE_URL to DATABASE_URL... done 

mio requirements.txt:

Django==1.4.2 
wsgiref==0.1.2 
dj-database-url==0.2.1 

Un frammento dal mio settings.py:

print "Got here before!\n" 
try: 
    import dj_database_url 
    DATABASES = { 'default': dj_database_url.config(default='postgres://localhost') } 
except: 
    print "Unexpected error:", sys.exc_info() 

print DATABASES 

Quando Spingo su heroku, ottengo questo da heroku logs:

heroku[slugc]: Slug compilation finished 
heroku[web.1]: Starting process with command `python ./manage.py runserver 0.0.0.0:30550 --noreload` 
app[web.1]: Got here before! 
app[web.1]: 
app[web.1]: {'default': {'ENGINE': 'django.db.backends.postgresql_psycopg2', 'NAME': '<blah blah>', 'HOST': 'ec2-<iip-address>.compute-1.amazonaws.com', 'USER': '<blah blah>', 'PASSWORD': '<blah>', 'PORT': 5432}} 
app[web.1]: 
app[web.1]: Validating models... 
app[web.1]: Traceback (most recent call last): 
app[web.1]: File "./manage.py", line 10, in <module> 
app[web.1]:  execute_from_command_line(sys.argv) 
app[web.1]:  utility.execute() 
app[web.1]:  self.execute(*args, **options.__dict__) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run_from_argv 
app[web.1]:  self.fetch_command(subcommand).run_from_argv(self.argv) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/__init__.py", line 443, in execute_from_command_line 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/__init__.py", line 382, in execute 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute 
app[web.1]:  self.inner_run(*args, **options) 
app[web.1]:  self.validate(display_num_errors=True) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 91, in inner_run 
app[web.1]:  num_errors = get_validation_errors(s, app) 
app[web.1]:  self.run(*args, **options) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/utils.py", line 92, in __getitem__ 
app[web.1]:  output = self.handle(*args, **options) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/validation.py", line 23, in get_validation_errors 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module 
app[web.1]:  from django.db import models, connection 
app[web.1]:  return import_module('.base', backend_name) 
app[web.1]:  __import__(name) 
app[web.1]: ImportError: No module named psycopg2.extensions 
app[web.1]:  return getattr(connections[DEFAULT_DB_ALIAS], item) 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/creation.py", line 1, in <module> 
app[web.1]:  backend = load_backend(db['ENGINE']) 
app[web.1]:  import psycopg2.extensions 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/__init__.py", line 40, in <module> 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 69, in handle 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 80, in run 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/utils.py", line 24, in load_backend 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/core/management/base.py", line 266, in validate 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/__init__.py", line 34, in __getattr__ 
app[web.1]:  backend = load_backend(connection.settings_dict['ENGINE']) 
app[web.1]:  from django.db.backends.postgresql_psycopg2.creation import DatabaseCreation 
app[web.1]: File "/app/.heroku/venv/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 13, in <module> 
heroku[web.1]: Process exited with status 1 
heroku[web.1]: State changed from starting to crashed 

Answer 1

È necessario aggiungere l'installazione psycopg2 al file requirements.txt. È l'adattatore del database: il modo in cui Python si interfaccia con PostgreSQL non è necessario installarlo perché lo fa heroku.

Basta aggiungere la riga psycopg2==2.4.4 al file requirements.txt.

La stessa aggiunta del database stesso, a proposito, non è necessaria. dj-database-url si prende cura di esso automaticamente. Guarda il heroku docs per una guida passo-passo.