Connection error when trying to call the Nylas API with retry

In few Nylas APIs I was facing NylasSdkTimeoutError so I wrapped the function with decorator to retry requests after some delay but now I’m getting error as follows:

urllib3.exceptions.ProtocolError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response'))

Sharing the retry decorator:

def retry(max_retries=3, backoff=2):
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            for attempt in range(1, max_retries + 1):
                try:
                    return func(*args, **kwargs)
                except NylasSdkTimeoutError:
                    if attempt == max_retries:
                        return {"success": False, "code": 504, "message": "Taking longer than expected. Please try again"}
                    time.sleep(backoff * (2 ** (attempt - 1)))
        return wrapper
    return decorator

how to resolve this issue? what’s the reason behind getting NylasSdkTimeoutError?

Hello lsr2001,

Understanding NylasSdkTimeoutError and ProtocolError Issues

The issues you’re experiencing are related to timeout handling and connection management in the Nylas Python SDK. Let me break down what’s happening and provide solutions.

What causes NylasSdkTimeoutError?

NylasSdkTimeoutError occurs when the Nylas SDK times out before receiving a response from the server1. This happens when:

  1. Network latency - Slow network connections or high server load

  2. Large data operations - Processing large amounts of email/calendar data

  3. Server-side delays - Provider API limitations (Gmail, Exchange, etc.)

  4. Default timeout too low - The default timeout is 90 seconds2, which may not be sufficient for some operations

The error is raised in the HttpClient when requests.exceptions.Timeout occurs3:

except requests.exceptions.Timeout as exc:
    raise NylasSdkTimeoutError(url=request["url"], timeout=timeout) from exc

Why you’re getting ProtocolError after adding retry logic

The urllib3.exceptions.ProtocolError: 'Remote end closed connection without response' occurs because:

  1. Connection reuse issues: Your retry decorator is reusing HTTP connections that the server has already closed

  2. Session management: The underlying requests session keeps connections alive, but the server/proxy closes them between retries

  3. Exponential backoff timing: The delays may not account for server connection timeouts

Improved Solutions

1. Configure Timeout Properly

Instead of just retrying, first increase the timeout for operations that need more time:

from nylas import Client

# Initialize with longer timeout
client = Client(
    api_key="your-api-key",
    timeout=300  # 5 minutes instead of default 90 seconds
)

# Or override timeout per request
messages = client.messages.list(
    "grant-id", 
    overrides={"timeout": 180}  # 3 minutes for this specific request
)

2. Enhanced Retry Decorator

Improve your retry logic to handle both timeout and connection errors:

import time
from functools import wraps
from nylas.models.errors import NylasSdkTimeoutError
import urllib3.exceptions
import requests.exceptions

def retry_with_backoff(max_retries=3, backoff=2, max_backoff=60):
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            last_exception = None
            
            for attempt in range(1, max_retries + 1):
                try:
                    return func(*args, **kwargs)
                    
                except (NylasSdkTimeoutError, 
                        urllib3.exceptions.ProtocolError, 
                        requests.exceptions.ConnectionError,
                        requests.exceptions.Timeout) as e:
                    
                    last_exception = e
                    
                    if attempt == max_retries:
                        return {
                            "success": False, 
                            "code": 504, 
                            "message": f"Request failed after {max_retries} attempts: {str(e)}"
                        }
                    
                    # Calculate backoff with jitter and max limit
                    backoff_time = min(backoff * (2 ** (attempt - 1)), max_backoff)
                    jitter = backoff_time * 0.1 * (0.5 - random.random())  # ±5% jitter
                    sleep_time = backoff_time + jitter
                    
                    print(f"Attempt {attempt} failed: {str(e)}. Retrying in {sleep_time:.2f} seconds...")
                    time.sleep(sleep_time)
                    
                except Exception as e:
                    # Don't retry on non-network errors
                    return {
                        "success": False,
                        "code": 500,
                        "message": f"Non-retryable error: {str(e)}"
                    }
            
            return {
                "success": False,
                "code": 504,
                "message": f"All retry attempts failed. Last error: {str(last_exception)}"
            }
        return wrapper
    return decorator

3. Connection Management Strategy

Create a new client instance for each retry attempt to avoid connection reuse issues:

def get_fresh_client():
    return Client(
        api_key="your-api-key",
        timeout=180  # 3 minutes
    )

@retry_with_backoff(max_retries=3, backoff=2)
def fetch_messages_with_fresh_connection(grant_id):
    client = get_fresh_client()  # Fresh connection each retry
    return client.messages.list(grant_id)

4. Request-Level Overrides

Use the built-in request override system for fine-grained control4:

def make_robust_request(client, operation, **kwargs):
    overrides = {
        "timeout": 300,  # 5 minutes
        "headers": {"Connection": "close"}  # Disable keep-alive
    }
    
    try:
        return operation(**kwargs, overrides=overrides)
    except (NylasSdkTimeoutError, urllib3.exceptions.ProtocolError) as e:
        # Handle specific error cases
        return handle_connection_error(e)

5. Comprehensive Error Handling

class NylasErrorHandler:
    def __init__(self, client):
        self.client = client
    
    def execute_with_retry(self, operation, *args, **kwargs):
        max_attempts = 3
        base_timeout = 90
        
        for attempt in range(max_attempts):
            try:
                # Increase timeout with each attempt
                timeout = base_timeout * (attempt + 1)
                overrides = kwargs.get('overrides', {})
                overrides['timeout'] = timeout
                kwargs['overrides'] = overrides
                
                return operation(*args, **kwargs)
                
            except NylasSdkTimeoutError as e:
                if attempt == max_attempts - 1:
                    return self._handle_timeout_error(e, attempt + 1)
                time.sleep(2 ** attempt)  # Exponential backoff
                
            except urllib3.exceptions.ProtocolError as e:
                if attempt == max_attempts - 1:
                    return self._handle_protocol_error(e, attempt + 1)
                time.sleep(5)  # Longer wait for connection issues
                
    def _handle_timeout_error(self, error, attempts):
        return {
            "success": False,
            "error": "timeout",
            "message": f"Request timed out after {attempts} attempts. Try increasing timeout or checking server load.",
            "url": getattr(error, 'url', 'unknown'),
            "timeout": getattr(error, 'timeout', 'unknown')
        }
    
    def _handle_protocol_error(self, error, attempts):
        return {
            "success": False,
            "error": "connection",
            "message": f"Connection closed by server after {attempts} attempts. This may indicate server-side issues.",
            "details": str(error)
        }

# Usage
handler = NylasErrorHandler(client)
result = handler.execute_with_retry(
    client.messages.list, 
    "grant-id",
    limit=100
)

Best Practices

  1. Start with timeout configuration before implementing retries

  2. Use fresh connections for retry attempts when possible

  3. Implement exponential backoff with jitter to avoid thundering herd

  4. Set maximum backoff limits to prevent excessive delays

  5. Log detailed error information for debugging

  6. Consider the specific API operation - some operations naturally take longer

  7. Monitor retry patterns to identify systematic issues

The ProtocolError typically indicates server-side connection management issues rather than client problems, so focus on robust error handling rather than trying to “fix” the underlying connection behavior.

Thank you so much @Josias_M for the detailed response. I went through your text and made updates in my integration class. Can you please check if this is correct?

import time
import requests
import urllib3

from nylas import Client
from nylas.models.errors import NylasApiError, NylasSdkTimeoutError
from nylas.config import RequestOverrides
from dataclasses import asdict
from functools import wraps

nylas = Client(api_key=<NYLAS_API_KEY>, api_uri=<NYLAS_API_URI>, timeout=180)
REDIRECT_URI = f"<path>"
SHORT_TIMEOUT = RequestOverrides(timeout=30)
LONG_TIMEOUT = RequestOverrides(timeout=60)


def retry(max_retries=3, backoff=2):
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            for attempt in range(1, max_retries + 1):
                try:
                    return func(*args, **kwargs)
                except (
                    NylasSdkTimeoutError,
                    requests.exceptions.ConnectionError,
                    urllib3.exceptions.ProtocolError,
                    requests.exceptions.Timeout
                ) as e:
                    if attempt == max_retries:
                        return {
                            "success": False,
                            "code": 504,
                            "message": "We couldn't get a response from your connected calendar in time. Please give it another try later",
                        }
                    time.sleep(backoff * (2 ** (attempt - 1)))
                except Exception as e:
                    # Don't retry on non-network errors
                    return {
                        "success": False,
                        "code": 500,
                        "message": f"Non-retryable error: {str(e)}"
                    }

        return wrapper

    return decorator


class NylasIntegration:
    def __init__(self, grant_id, *args, **kwargs):
        self.grant_id = grant_id

    @retry()
    def get_nylas_event(self, event_id):
        try:
            resp = nylas.events.find(
                identifier=self.grant_id,
                event_id=event_id,
                query_params={
                    "calendar_id": "primary",
                },
                overrides=SHORT_TIMEOUT
            )
            return {"success": True, "data": asdict(resp.data)}
        except NylasApiError:
            return {"success": False, "code": 500, "message": "Something went wrong"}

    ```

Hello Isr2001,

I’ve reviewed your code and found a small issue:

Main Issue: RequestOverrides Usage :cross_mark:

RequestOverrides is a TypedDictconfig.py, not a class you can instantiate. This line will fail:

SHORT_TIMEOUT = RequestOverrides(timeout=30)  # ❌ Won't work

Fix: Use dictionary literals instead:

SHORT_TIMEOUT = {"timeout": 30}
LONG_TIMEOUT = {"timeout": 60}

:warning: Potential Issue in Retry Logic:

Your exception handling might catch NylasApiError in the general except Exception block, preventing retries for API errors. If this is intentional (API errors shouldn’t retry), consider being explicit:

except NylasApiError as e:
    # Don't retry API errors - they won't succeed on retry
    return {
        "success": False,
        "code": e.status_code or 500,
        "message": str(e)
    }
except (
    NylasSdkTimeoutError,
    requests.exceptions.ConnectionError,
    urllib3.exceptions.ProtocolError,
    requests.exceptions.Timeout
) as e:
    # Retry logic here
    ...

Everything else looks good!