CODEWITHSUNDEEP
pythonjsonpython-2.7io
Will Beauchamp
Will Beauchamp

Reputation: 579

Python: json.load() error, every time

I generate a large nested dictionary and then save it as a json, then later on I try to load it (so that I can append more data to the json). However I am constantly getting an error on the following line of code:

 # to save
 with open(json_path,'w') as f:
    json.dump(data, f, indent=3, sort_keys=True)

 # to load
 with open(json_path,'r') as f:
    data = json.load(f)

Errors I have seen so far:
ValueError: end is out of bounds
ValueError: expecting object ...
ValueError: unterminated string ...

But the strange thing is: if I pdb after the exception and try to load the json again, it works everytime!

Upvotes: 0

Views: 608

Answers (1)

Martijn Pieters
Martijn Pieters

Reputation: 1122182

You are reading too early, and the write hasn't completed yet. If you are using separate processes or threads, you'll need to make sure you serialise read and write operations.

Use a lock to make sure the write operation completes before you attempt to read.

Upvotes: 1

Related Questions