Streamline optional dependency sqlmodel

[nsheff]

In db_helpers.py, we're using a try block to wrap the sqlmodel import:

try:
    from sqlmodel import and_, or_, Integer, Float, String, Boolean
except:
    pass

But in db_parsed_schema.py, and dbbackend.py we are not:

from sqlmodel import Field, SQLModel

Will this break things if sqlmodel is not installed?

Also, is there a better way to isolate the sqlmodel optionality into a single place? For example, I'm thinking of something like importing sqlmodel in an __init__.py under backends/db_backend` and then having these show up in everything in that module, so that it doesn't have to be repeatedly imported? (not sure if this will work)

[nsheff]

One way I'm doing this in geniml that is working is something like this:

# first, set a const so we know whether the dep is satisfied or not
try:
    import hnswlib
    DEP_HNSWLIB = True
except ImportError:
    DEP_HNSWLIB = False
    _LOGGER.error(
        "HNSWBackend requires hnswlib. Install hnswlib, or ignore this if you don't need HNSWBackend"
    )


if not DEP_HNSWLIB:
    # Dependency not met;  make dummy class so code can instantiate, but it brakes if actually used
    class HNSWBackend(EmSearchBackend):
        pass

else:
    # dependency met, make the real class
    class HNSWBackend(EmSearchBackend):
        """A search backend that uses a local HNSW index to store and search embeddings"""
        ...

it's nice to keep this logic to a single place to make maintenance easier

[donaldcampbelljr]

This is currently the code for checking dependencies for the DB backend (within pipestat.py).:

pipestat/pipestat/pipestat.py

Lines 55 to 90 in 37c7311

	try:
	from pipestat.backends.db_backend.db_parsed_schema import (
	ParsedSchemaDB as ParsedSchema,
	)
	except ImportError:
	from .parsed_schema import ParsedSchema
	try:
	from pipestat.backends.db_backend.dbbackend import DBBackend
	from pipestat.backends.db_backend.db_helpers import construct_db_url
	except ImportError:
	# We let this pass, but if the user attempts to create DBBackend, check_dependencies raises exception.
	pass
	_LOGGER = getLogger(PKG_NAME)
	def check_dependencies(dependency_list: list = None, msg: str = None):
	"""Decorator to check that the dependency list has successfully been imported."""
	def wrapper(func):
	def inner(*args, **kwargs):
	dependencies_satisfied = True
	if dependency_list is not None:
	for i in dependency_list:
	if i not in globals():
	_LOGGER.warning(msg=f"Missing dependency: {i}")
	dependencies_satisfied = False
	if dependencies_satisfied is False:
	raise PipestatDependencyError(msg=msg)
	return func(*args, **kwargs)
	return inner
	return wrapper

To answer the above question

But in db_parsed_schema.py, and dbbackend.py we are not:

from sqlmodel import Field, SQLModel

Will this break things if sqlmodel is not installed?

Lines 55-90 will allow for sqlmodel to not be installed.

Also, I do think that the lines from dbhelpers.py do not need to be in a try: except:

pipestat/pipestat/backends/db_backend/db_helpers.py

Lines 5 to 8 in 37c7311

	try:
	from sqlmodel import and_, or_, Integer, Float, String, Boolean
	except ImportError as e:
	pass

    from sqlmodel import and_, or_, Integer, Float, String, Boolean