Firebase Firestore: get generated ID of document (Python)

Question

I can create a new document (with auto generated ID), and store a reference to it like this:

my_data = {"key": "value"}
doc_ref = db.collection(u'campaigns').add(my_data)

I can access the data itself like:

print (doc_ref[0]) # prints {"key": "value"}

But when I try to access the doc_ref ID, I am unable to:

# All of these throw attribute errors
doc_ref.get()
doc_ref.data()
doc_ref.id

There are other posts which suggest how to do this in Javascript, but none which work for the Python SDK!

How can I access the generated ID of a document I created?

Answer 1

The documentation is unclear, but I finally got it to work:

doc_ref = db.collection(u'campaigns').document()
doc_ref.set(my_data)
print(doc_ref.id)

Answer 2

To get ID after save on Python:

This will return for instance some id like wlJQKyVDsIIpX0x3NBmt

doc_ref = db.collection('promotions').add(data)
return doc_ref[1].id