How to capture botocore's NoSuchKey exception?
PythonBotocorePython Problem Overview
I'm trying to write "good" python and capture a S3 no such key error with this:
session = botocore.session.get_session()
client = session.create_client('s3')
try:
client.get_object(Bucket=BUCKET, Key=FILE)
except NoSuchKey as e:
print >> sys.stderr, "no such key in bucket"
But NoSuchKey isn't defined and I can't trace it to the import I need to have it defined.
e.__class__ is botocore.errorfactory.NoSuchKey but from botocore.errorfactory import NoSuchKey gives an error and from botocore.errorfactory import * doesn't work either and I don't want to capture a generic error.
Python Solutions
Solution 1 - Python
from botocore.exceptions import ClientError
try:
response = self.client.get_object(Bucket=bucket, Key=key)
return json.loads(response["Body"].read())
except ClientError as ex:
if ex.response['Error']['Code'] == 'NoSuchKey':
logger.info('No object found - returning empty')
return dict()
else:
raise
Solution 2 - Python
Using botocore 1.5, it looks like the client handle exposes the exception classes:
session = botocore.session.get_session()
client = session.create_client('s3')
try:
client.get_object(Bucket=BUCKET, Key=FILE)
except client.exceptions.NoSuchKey as e:
print >> sys.stderr, "no such key in bucket"
Solution 3 - Python
In boto3, I was able to access the exception in resource's meta client.
import boto3
s3 = boto3.resource('s3')
s3_object = s3.Object(bucket_name, key)
try:
content = s3_object.get()['Body'].read().decode('utf-8')
except s3.meta.client.exceptions.NoSuchKey:
print("no such key in bucket")
Solution 4 - Python
I think the most elegant way to do this is in Boto3 is
session = botocore.session.get_session()
client = session.create_client('s3')
try:
client.get_object(Bucket=BUCKET, Key=FILE)
except client.exceptions.NoSuchKey:
print("no such key in bucket")
The documentation on error handling seems sparse, but the following prints the error codes this works for:
session = botocore.session.get_session()
client = session.create_client('s3')
try:
try:
client.get_object(Bucket=BUCKET, Key=FILE)
except client.exceptions.InvalidBucketName:
print("no such key in bucket")
except AttributeError as err:
print(err)
> < botocore.errorfactory.S3Exceptions object at 0x105e08c50 > object has no attribute 'InvalidBucketName'. Valid exceptions are: BucketAlreadyExists, BucketAlreadyOwnedByYou, NoSuchBucket, NoSuchKey, NoSuchUpload, ObjectAlreadyInActiveTierError, ObjectNotInActiveTierError