Custom PyPI Index Configuration in PDM

[berthin]

Hi,

I'm trying to understand the correct way to configure a custom PyPI index in a PDM-managed project.

Initially, I added the index to my pyproject.toml like this:

[[tool.pdm.source]]
name = "pypi-simple"
url = "https://my-server.com/pypi/simple"
verify_ssl = true
ca_certs = "/path/to/cert.pem"

However, when I run pdm add package, I get [ConnectError]: [Errno 99] Cannot assign requested address.

Then, if I instead create a pdm.toml file with the following:

[pypi]
url = "https://my-server.com/pypi/simple"
ca_certs = "/path/to/cert.pem"

... everything works file.

This has left me confused about the correct usage. I expected that defining sources in pyproject.toml would be sufficient for PDM to use the custom index when installing packages. Also, unlike Poetry, the pdm.lock file doesn’t seem to indicate which index a package was pulled from.

Could you clarify:

• What is the correct and recommended way to configure a custom PyPI index in PDM?
• Why does the pyproject.toml approach not work as expected?
• Is there a way to confirm (e.g. pdm.lock?) which source a package came from? In case of having multiple indexes.

The poetry.lock file looks like:

[package.source]
type = "legacy"
url = "https://my-server.com/pypi/simple"
reference = "pypi-simple"

[[package]]
name = "certifi"
...

So, it's clear where the package comes from.

Thanks