Flask Max Recursion Depth

Question

I have a max recursion depth error that is driving me nuts

In the flask __init__.py file I have:

@app.route('/vpcs')
@app.route('/vpcs/<vpc>')
def getVPCs(vpc=False):
    """
    Get the vpcs.
    """
    results = getVPCs()
    return jsonify(**results)

It calls the functions from:

def getVPCs():
   """
   This is the function that loops through the accounts and regions and does all the connections.
   """

A function that loops through the config file with the account keys

   accounts = getAccountCreds()

   vpc_list = []
   try:

Loop through each region ... # for each region for r in REGIONS:

Loop through each of the accounts

       # for each of the 8,yes 8, AWS accounts...
       for account,keys in accounts.iteritems():
         conn = VPCConnection(region=ec2.get_region(r),aws_access_key_id=keys[0],aws_secret_access_key=keys[1])

Get all the VPCs for each account ...

          vpcs = conn.get_all_vpcs()
          if formatVPC(account,vpcs[0]):
                vpc_list.append(formatVPC(account,vpcs[0]))
            return vpc_list
  except boto.exception.BotoServerError, e:
    print e

Which also calls:

def formatVPC(account,instance):
    """
    Function to format VPC data. 
    Keys we want: 
    - id
    - instance_tenancy
    - tags
    - region.name
    - region.connection
    - region.endpoint
    - state
    - cidr_block
    """
    result_dict = {}
    if instance:
        result_dict['account'] = account
        result_dict['id'] = instance.id
        result_dict['cidr_block'] = instance.cidr_block
        result_dict['instance_tenancy'] = instance.instance_tenancy
        result_dict['region'] = {'name':instance.region.name,'connection':   instance.region.connection,'endpoint':instance.region.endpoint}

        if result_dict:
            return result_dict

Error:

Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/Library/Python/2.7/site-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/Library/Python/2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/Library/Python/2.7/site-packages/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)

`getVPCs()` calls itself forever. – Joel Cornett Apr 03 '15 at 02:40 — Joel Cornett, Apr 03 '15 at 02:40

Unit03 · Accepted Answer · 2015-04-03T03:01:12.997

It calls the functions from:

Nope, the getVPCs from your snippet just calls itself:

@app.route('/vpcs')
@app.route('/vpcs/<vpc>')
def getVPCs(vpc=False):
    """
    Get the vpcs.
    """
    results = getVPCs()  # Here.
    return jsonify(**results)

and does so recursively, without any "boundary" other than recursion limit, which results in RuntimeError: maximum recursion depth exceededyou've mentioned.

Change one of these functions' names (and, of course, adjust the call if necessary).

score -3 · Answer 2 · answered Apr 03 '15 at 02:34

https://docs.python.org/2/library/sys.html

sys.getrecursionlimit() Return the current value of the recursion limit, the maximum depth of the Python interpreter stack. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python. It can be set by setrecursionlimit().

Flask Max Recursion Depth

2 Answers2