Hey, now I am trying to configure psycopg2 in my django proj settings.py running

./pants run projects/appsflyer/:manage -- createsuperuser

throws:

django.core.exceptions.ImproperlyConfigured: settings.DATABASES is improperly configured. Please supply the ENGINE value. Check settings documentation for more details.

my settings.py file:

...
...
DATABASES = {
   'default': {
       'ENGINE': 'django.db.backends.postgresql',
       'NAME': '<database_name>',
       'USER': '<database_username>',
       'PASSWORD': '<password>',
       'HOST': '<database_hostname_or_ip>',
       'PORT': '<database_port>',
   }
}

BUILD

python_sources()

resource(
    name="env",
    source=".env"
)

pex_binary(
    name="manage",
    entry_point="manage.py",
    dependencies=[
        "./appsflyer:appsflyer",
        ":env"
    ],
    restartable=True
)

Pants auto-infers any

import ...

or

from ... import ...

(and some weirder cases), but it is not magic. If the settings aren't imported by your code, you may need to add a manual dependency.

You can also try turning on this option: https://www.pantsbuild.org/docs/reference-python-infer#section-string-imports

I tried this -

./pants filedeps --transitive ./appsflyer:appsflyer

and settings.py was not there. I tried adding a new source in projects/appsflyer/appsflyer/BUILD (this dir has settings.py)

python_sources()

python_source(
    name="settings",
    source="settings.py",
)

Then added that as dependency in the projects/appsflyer/BUILD (this dir has manage.py)

python_sources()

resource(
    name="env",
    source=".env"
)

pex_binary(
    name="manage",
    entry_point="manage.py",
    dependencies=[
        "./appsflyer:appsflyer",
        ":env",
        "./appsflyer:settings",
    ],
    restartable=True
)

But this doesn't add the settings.py as filedep in the toplevel appsflyer. How to do that?

You need to make your

python_sources

dependencies inside

appsflyer

on

:settings

This way you don’t need to explicitly mention it outside of the directory

appsflyer

I am not able to follow. Can you please guilde me a little more? For clarity I have update the BUILD file locations above.

This build file projects/appsflyer/appsflyer/BUILD

python_sources(dependencies=[":settings"])

python_source(
    name="settings",
    source="settings.py",
)

then your other projects/appsflyer/BUILD

python_sources()

resource(
    name="env",
    source=".env"
)

pex_binary(
    name="manage",
    entry_point="manage.py",
    dependencies=[
        "./appsflyer:appsflyer",
        ":env",
    ],
    restartable=True
)

Also I don’t think you need to put an explicit dependency inside

pex_binary

on

./appsflyer:appsflyer

. Pants will be able to infer the implicit dependency as long as you import the code from appsflyer somewhere inside

manage.py

.

This still doesn't fix it.

> ./pants filedeps --transitive projects/appsflyer:appsflyer
BUILD
projects/appsflyer/BUILD
projects/appsflyer/manage.py
pyproject.toml

and even without adding the :settings target dependency I get settings.py in sources.

> ./pants list projects/appsflyer/appsflyer/:

projects/appsflyer/appsflyer:appsflyer
projects/appsflyer/appsflyer/__init__.py
projects/appsflyer/appsflyer/asgi.py
projects/appsflyer/appsflyer/settings.py
projects/appsflyer/appsflyer/urls.py
projects/appsflyer/appsflyer/wsgi.py

And what does not having settings.py in filedep mean. We also don't have urls.py and wsgi.py in filedeps.

Can you try?

./pants dependencies --transitive projects/appsflyer:appsflyer

https://www.pantsbuild.org/docs/project-introspection#dependencies---find-a-targets-dependencies

filedeps

outputs all of the files belonging to a target, based on its

sources

field. I would read this a bit https://www.pantsbuild.org/docs/project-introspection

> ./pants dependencies --transitive projects/appsflyer:appsflyer
//:poetry#Django
//pyproject.toml:poetry
projects/appsflyer/manage.py

btw what should I expect here? moreover, I see settings.py here.

> ./pants filedeps --transitive projects/appsflyer:manage   
BUILD
projects/appsflyer/.env
projects/appsflyer/BUILD
projects/appsflyer/appsflyer/BUILD
projects/appsflyer/appsflyer/__init__.py
projects/appsflyer/appsflyer/asgi.py
projects/appsflyer/appsflyer/settings.py. <----HERE
projects/appsflyer/appsflyer/urls.py
projects/appsflyer/appsflyer/wsgi.py
projects/appsflyer/manage.py
pyproject.toml

Since the command run is actually

./pants run projects/appsflyer/:manage -- createsuperuser

then why do we check the

projects/appsflyer:appsflyer

target? I feel like I am missing something conceptual here.

Hey you are correct that we should be more concerned about the

pex_binary

and its dependencies. Whatever I had suggested was for debugging purpose. I also realised that the

python_sources

should automatically include

settings.py

inside the

projects/appsflyer/appsflyer/BUILD

since it’s just a glob of all

*.py

files inside the directory. So creating a settings using

python_source

wasn’t needed. At the end it’s

pex_binary

which figures out from the universe of all these sources and dependencies what it should package. Hence you do need to provide an explicit dependency on

settings.py

based target if

pex_binary

can’t figure it out itself.

Alright, so point taken that if in case some dependency is not being picked up automatically, we need to mention it explicitly. But it is still not working. I changed as you suggested projects/appsflyer/appsflyer/BUILD

python_sources(
    dependencies=[
        ":settings"
    ]
)

python_source(
    name="settings",
    source="settings.py",
    dependencies=["//:poetry#psycopg2-binary"]
)

Since the error has not even reached the psycopg2 dependency level, it not even able to find the engine value in the first place. So it looks like that even settings.py is not avl for the binary, though the output of the following cmds is:

> ./pants dependencies --transitive projects/appsflyer:manage
//:poetry#Django
//:poetry#apig-wsgi
//:poetry#psycopg2-binary
//:poetry#python-decouple
//pyproject.toml:poetry
projects/appsflyer/appsflyer/__init__.py
projects/appsflyer/appsflyer/asgi.py
projects/appsflyer/appsflyer/settings.py
projects/appsflyer/appsflyer/urls.py
projects/appsflyer/appsflyer/wsgi.py
projects/appsflyer/appsflyer:settings <--- HERE
projects/appsflyer/manage.py
projects/appsflyer:env

> ./pants filedeps --transitive projects/appsflyer:manage
BUILD
projects/appsflyer/.env
projects/appsflyer/BUILD
projects/appsflyer/appsflyer/BUILD
projects/appsflyer/appsflyer/__init__.py
projects/appsflyer/appsflyer/asgi.py
projects/appsflyer/appsflyer/settings.py <--- HERE
projects/appsflyer/appsflyer/urls.py
projects/appsflyer/appsflyer/wsgi.py
projects/appsflyer/manage.py
pyproject.toml

I am not really a django expert. From my minimal googling, I am trying to guess. How does django figure out location of settings.py ? I guess you aren’t explicitly importing it, right? In that case django reads some path. You need to make sure that path is available inside

pex_binary

@handsome-sunset-98068 I cannot repro. Here is a worked example using `django-admin startproject appsflyer`: https://github.com/jsirois/tarun-django-debug

OMG thanks for this repo that I could observe the diff...I can't believe I copied the wrong key in the DATABASES dictionary, hence it was saying ENGINE was not present. This issue is closed. And super thanks for the effort.