Error Handling and Troubleshooting

Common errors — invalid SMILES, missing API keys, HTTP/API failures, failed workflows, and polling — with verified handling for rowan-python 3.1.13.

Actual exception classes

rowan.ValidationError, rowan.AuthenticationError, and rowan.InsufficientCreditsError do not exist in SDK 3.1.13. Referencing one in an except clause raises AttributeError while handling the original failure.

Validate molecules before submission

from rdkit import Chem

smiles = "CCCC(CC"
mol = Chem.MolFromSmiles(smiles)
if mol is None:
    raise ValueError(f"Invalid SMILES: {smiles}")

Input types vary by workflow. For example, descriptors require a molecule object, while pKa accepts a SMILES string:

import rowan

try:
    rowan.submit_descriptors_workflow("CCO")
except ValueError as exc:
    print(f"Input problem: {exc}")

wf = rowan.submit_descriptors_workflow(rowan.Molecule.from_smiles("CCO"))

Authentication and API errors

import httpx
import rowan

try:
    user = rowan.whoami()
except httpx.HTTPStatusError as exc:
    if exc.response.status_code == 401:
        print("Bad or missing API key — check ROWAN_API_KEY")
    else:
        # Includes credit limits and other API failures; inspect the response.
        print(exc.response.status_code, exc.response.text)
        raise

The SDK treats an environment variable set to an empty string as present. That produces 401 Could not validate credentials rather than a clear missing key error. Check that ROWAN_API_KEY is non-empty without printing the key:

import os

api_key = os.environ.get("ROWAN_API_KEY")
if not api_key:
    raise RuntimeError("ROWAN_API_KEY is missing or empty")

Use max_credits=N on submission calls to bound spend.

Server-side workflow failures

try:
    result = wf.result()
except rowan.WorkflowError as exc:
    print(f"Workflow failed: {exc}")
    print(f"Status: {wf.get_status()}")

Polling and non-blocking checks

# Block and poll every five seconds.
result = wf.result(wait=True, poll_interval=5)

# Or check without blocking.
if not wf.done():
    print(f"Still running: {wf.get_status()}")
else:
    result = wf.result(wait=False)

WorkflowResult.complete is a boolean, not a percent-done value. For coarse status, use wf.get_status() and wf.fetch_latest().

Debugging tips

• Inspect result.data when a convenience property is unavailable.
• Save workflow UUIDs and reconnect with rowan.retrieve_workflow(uuid).
• Use dir(result) to discover properties for that result class; they differ.
• Validate SMILES locally with RDKit before any paid submission.