Jak obsługiwać błędy w boto3?

Próbuję wymyślić, jak prawidłowo obsługiwać błędy w boto3.

Próbuję utworzyć użytkownika IAM:

def create_user(username, iam_conn):
    try:
        user = iam_conn.create_user(UserName=username)
        return user
    except Exception as e:
        return e

Gdy wywołanie użytkownika create_user się powiedzie, otrzymuję zgrabny obiekt, który zawiera kod statusu HTTP wywołania API i dane nowo utworzonego użytkownika.

Przykład:

{'ResponseMetadata': 
      {'HTTPStatusCode': 200, 
       'RequestId': 'omitted'
      },
 u'User': {u'Arn': 'arn:aws:iam::omitted:user/omitted',
           u'CreateDate': datetime.datetime(2015, 10, 11, 17, 13, 5, 882000, tzinfo=tzutc()),
           u'Path': '/',
           u'UserId': 'omitted',
           u'UserName': 'omitted'
          }
}

To działa świetnie. Ale kiedy to się nie powiedzie (na przykład, jeśli użytkownik już istnieje), po prostu dostaję obiekt typu botocore.exceptions.ClientError z samym tekstem, aby powiedzieć mi, co poszło nie tak.

Przykład: ClientError („Wystąpił błąd (EntityAlreadyExists) podczas wywoływania operacji CreateUser: Użytkownik z pominiętą nazwą już istnieje.”,)

To (AFAIK) bardzo utrudnia obsługę błędów, ponieważ nie mogę po prostu włączyć wynikowego kodu stanu HTTP (409 dla użytkownika już istnieje zgodnie z dokumentacją API AWS dla IAM). To sprawia, że ​​myślę, że muszę robić coś w niewłaściwy sposób. Optymalnym sposobem byłoby, aby boto3 nigdy nie zgłaszał wyjątków, ale juty zawsze zwracają obiekt odzwierciedlający przebieg wywołania API.

Czy ktoś może oświecić mnie w tej sprawie lub skierować mnie we właściwym kierunku?

Użyj odpowiedzi zawartej w wyjątku. Oto przykład:

import boto3
from botocore.exceptions import ClientError

try:
    iam = boto3.client('iam')
    user = iam.create_user(UserName='fred')
    print("Created user: %s" % user)
except ClientError as e:
    if e.response['Error']['Code'] == 'EntityAlreadyExists':
        print("User already exists")
    else:
        print("Unexpected error: %s" % e)

Dykt odpowiedzi w wyjątku będzie zawierał:

• ['Error']['Code'] np. „EntityAlreadyExists” lub „ValidationError”
• ['ResponseMetadata']['HTTPStatusCode'] np. 400
• ['ResponseMetadata']['RequestId'] np. „d2b06652-88d7-11e5-99d0-812348583a35”
• ['Error']['Message'] np. „Wystąpił błąd (EntityAlreadyExists) ...”
• ['Error']['Type'] np. „Nadawca”

Aby uzyskać więcej informacji, zobacz Obsługa błędów botocore .

[Zaktualizowano: 2018-03-07]

Zestaw AWS Python SDK zaczął ujawniać wyjątki usług na klientach (choć nie w zasobach ), które można jawnie wychwycić, dzięki czemu można teraz napisać ten kod w taki sposób:

import boto3
from botocore.exceptions import ClientError, ParamValidationError

try:
    iam = boto3.client('iam')
    user = iam.create_user(UserName='fred')
    print("Created user: %s" % user)
except iam.exceptions.EntityAlreadyExistsException:
    print("User already exists")
except ParamValidationError as e:
    print("Parameter validation error: %s" % e)
except ClientError as e:
    print("Unexpected error: %s" % e)

Niestety obecnie nie ma dokumentacji dotyczącej tych wyjątków.

Uważam, że jest to bardzo przydatne, ponieważ wyjątki nie są udokumentowane, aby wyświetlić listę wszystkich wyjątków na ekranie tego pakietu. Oto kod, którego użyłem, aby to zrobić:

import botocore.exceptions
def listexns(mod):
    #module = __import__(mod)
    exns = []
    for name in botocore.exceptions.__dict__:
        if (isinstance(botocore.exceptions.__dict__[name], Exception) or
            name.endswith('Error')):
            exns.append(name)
    for name in exns:
        print('%s.%s is an exception type' % (str(mod), name))
    return

if __name__ == '__main__':
    import sys
    if len(sys.argv) <= 1:
        print('Give me a module name on the $PYTHONPATH!')
    print('Looking for exception types in module: %s' % sys.argv[1])
    listexns(sys.argv[1])

Co skutkuje w:

Looking for exception types in module: boto3
boto3.BotoCoreError is an exception type
boto3.DataNotFoundError is an exception type
boto3.UnknownServiceError is an exception type
boto3.ApiVersionNotFoundError is an exception type
boto3.HTTPClientError is an exception type
boto3.ConnectionError is an exception type
boto3.EndpointConnectionError is an exception type
boto3.SSLError is an exception type
boto3.ConnectionClosedError is an exception type
boto3.ReadTimeoutError is an exception type
boto3.ConnectTimeoutError is an exception type
boto3.ProxyConnectionError is an exception type
boto3.NoCredentialsError is an exception type
boto3.PartialCredentialsError is an exception type
boto3.CredentialRetrievalError is an exception type
boto3.UnknownSignatureVersionError is an exception type
boto3.ServiceNotInRegionError is an exception type
boto3.BaseEndpointResolverError is an exception type
boto3.NoRegionError is an exception type
boto3.UnknownEndpointError is an exception type
boto3.ConfigParseError is an exception type
boto3.MissingParametersError is an exception type
boto3.ValidationError is an exception type
boto3.ParamValidationError is an exception type
boto3.UnknownKeyError is an exception type
boto3.RangeError is an exception type
boto3.UnknownParameterError is an exception type
boto3.AliasConflictParameterError is an exception type
boto3.PaginationError is an exception type
boto3.OperationNotPageableError is an exception type
boto3.ChecksumError is an exception type
boto3.UnseekableStreamError is an exception type
boto3.WaiterError is an exception type
boto3.IncompleteReadError is an exception type
boto3.InvalidExpressionError is an exception type
boto3.UnknownCredentialError is an exception type
boto3.WaiterConfigError is an exception type
boto3.UnknownClientMethodError is an exception type
boto3.UnsupportedSignatureVersionError is an exception type
boto3.ClientError is an exception type
boto3.EventStreamError is an exception type
boto3.InvalidDNSNameError is an exception type
boto3.InvalidS3AddressingStyleError is an exception type
boto3.InvalidRetryConfigurationError is an exception type
boto3.InvalidMaxRetryAttemptsError is an exception type
boto3.StubResponseError is an exception type
boto3.StubAssertionError is an exception type
boto3.UnStubbedResponseError is an exception type
boto3.InvalidConfigError is an exception type
boto3.InfiniteLoopConfigError is an exception type
boto3.RefreshWithMFAUnsupportedError is an exception type
boto3.MD5UnavailableError is an exception type
boto3.MetadataRetrievalError is an exception type
boto3.UndefinedModelAttributeError is an exception type
boto3.MissingServiceIdError is an exception type

Po prostu aktualizacja problemu „bez wyjątków dotyczących zasobów”, na co wskazuje @jarmod (prosimy o aktualizację odpowiedzi, jeśli wydaje się, że poniżej)

Przetestowałem poniższy kod i działa dobrze. Używa „zasobów” do robienia rzeczy, ale łapie client.exceptions- chociaż „wygląda” nieco źle… sprawdza się dobrze, klasy wyjątków są wyświetlane i dopasowywane, gdy patrzy się na użycie debuggera w czasie wyjątku…

Może nie dotyczyć wszystkich zasobów i klientów, ale działa w przypadku folderów danych (zwanych także segmentami s3).

lab_session = boto3.Session() 
c = lab_session.client('s3') #this client is only for exception catching

try:
    b = s3.Bucket(bucket)
    b.delete()
except c.exceptions.NoSuchBucket as e:
    #ignoring no such bucket exceptions
    logger.debug("Failed deleting bucket. Continuing. {}".format(e))
except Exception as e:
    #logging all the others as warning
    logger.warning("Failed deleting bucket. Continuing. {}".format(e))

Mam nadzieję że to pomoże...

Jak już wspomniano kilka innych, można wychwycić niektóre błędy za pomocą klienta usługi ( service_client.exceptions.<ExceptionClass>) lub resource ( service_resource.meta.client.exceptions.<ExceptionClass>), jednak nie jest to dobrze udokumentowane (także jakie wyjątki należą do których klientów). Oto więc, jak uzyskać pełne mapowanie w momencie pisania (styczeń 2020) w regionie UE (Irlandia) ( eu-west-1):

import boto3, pprint

region_name = 'eu-west-1'
session = boto3.Session(region_name=region_name)
exceptions = {
  service: list(boto3.client('sts').exceptions._code_to_exception)
  for service in session.get_available_services()
}
pprint.pprint(exceptions, width=20000)

Oto podzbiór dość dużego dokumentu:

{'acm': ['InvalidArnException', 'InvalidDomainValidationOptionsException', 'InvalidStateException', 'InvalidTagException', 'LimitExceededException', 'RequestInProgressException', 'ResourceInUseException', 'ResourceNotFoundException', 'TooManyTagsException'],
 'apigateway': ['BadRequestException', 'ConflictException', 'LimitExceededException', 'NotFoundException', 'ServiceUnavailableException', 'TooManyRequestsException', 'UnauthorizedException'],
 'athena': ['InternalServerException', 'InvalidRequestException', 'TooManyRequestsException'],
 'autoscaling': ['AlreadyExists', 'InvalidNextToken', 'LimitExceeded', 'ResourceContention', 'ResourceInUse', 'ScalingActivityInProgress', 'ServiceLinkedRoleFailure'],
 'cloudformation': ['AlreadyExistsException', 'ChangeSetNotFound', 'CreatedButModifiedException', 'InsufficientCapabilitiesException', 'InvalidChangeSetStatus', 'InvalidOperationException', 'LimitExceededException', 'NameAlreadyExistsException', 'OperationIdAlreadyExistsException', 'OperationInProgressException', 'OperationNotFoundException', 'StackInstanceNotFoundException', 'StackSetNotEmptyException', 'StackSetNotFoundException', 'StaleRequestException', 'TokenAlreadyExistsException'],
 'cloudfront': ['AccessDenied', 'BatchTooLarge', 'CNAMEAlreadyExists', 'CannotChangeImmutablePublicKeyFields', 'CloudFrontOriginAccessIdentityAlreadyExists', 'CloudFrontOriginAccessIdentityInUse', 'DistributionAlreadyExists', 'DistributionNotDisabled', 'FieldLevelEncryptionConfigAlreadyExists', 'FieldLevelEncryptionConfigInUse', 'FieldLevelEncryptionProfileAlreadyExists', 'FieldLevelEncryptionProfileInUse', 'FieldLevelEncryptionProfileSizeExceeded', 'IllegalFieldLevelEncryptionConfigAssociationWithCacheBehavior', 'IllegalUpdate', 'InconsistentQuantities', 'InvalidArgument', 'InvalidDefaultRootObject', 'InvalidErrorCode', 'InvalidForwardCookies', 'InvalidGeoRestrictionParameter', 'InvalidHeadersForS3Origin', 'InvalidIfMatchVersion', 'InvalidLambdaFunctionAssociation', 'InvalidLocationCode', 'InvalidMinimumProtocolVersion', 'InvalidOrigin', 'InvalidOriginAccessIdentity', 'InvalidOriginKeepaliveTimeout', 'InvalidOriginReadTimeout', 'InvalidProtocolSettings', 'InvalidQueryStringParameters', 'InvalidRelativePath', 'InvalidRequiredProtocol', 'InvalidResponseCode', 'InvalidTTLOrder', 'InvalidTagging', 'InvalidViewerCertificate', 'InvalidWebACLId', 'MissingBody', 'NoSuchCloudFrontOriginAccessIdentity', 'NoSuchDistribution', 'NoSuchFieldLevelEncryptionConfig', 'NoSuchFieldLevelEncryptionProfile', 'NoSuchInvalidation', 'NoSuchOrigin', 'NoSuchPublicKey', 'NoSuchResource', 'NoSuchStreamingDistribution', 'PreconditionFailed', 'PublicKeyAlreadyExists', 'PublicKeyInUse', 'QueryArgProfileEmpty', 'StreamingDistributionAlreadyExists', 'StreamingDistributionNotDisabled', 'TooManyCacheBehaviors', 'TooManyCertificates', 'TooManyCloudFrontOriginAccessIdentities', 'TooManyCookieNamesInWhiteList', 'TooManyDistributionCNAMEs', 'TooManyDistributions', 'TooManyDistributionsAssociatedToFieldLevelEncryptionConfig', 'TooManyDistributionsWithLambdaAssociations', 'TooManyFieldLevelEncryptionConfigs', 'TooManyFieldLevelEncryptionContentTypeProfiles', 'TooManyFieldLevelEncryptionEncryptionEntities', 'TooManyFieldLevelEncryptionFieldPatterns', 'TooManyFieldLevelEncryptionProfiles', 'TooManyFieldLevelEncryptionQueryArgProfiles', 'TooManyHeadersInForwardedValues', 'TooManyInvalidationsInProgress', 'TooManyLambdaFunctionAssociations', 'TooManyOriginCustomHeaders', 'TooManyOriginGroupsPerDistribution', 'TooManyOrigins', 'TooManyPublicKeys', 'TooManyQueryStringParameters', 'TooManyStreamingDistributionCNAMEs', 'TooManyStreamingDistributions', 'TooManyTrustedSigners', 'TrustedSignerDoesNotExist'],
 'cloudtrail': ['CloudTrailARNInvalidException', 'CloudTrailAccessNotEnabledException', 'CloudWatchLogsDeliveryUnavailableException', 'InsufficientDependencyServiceAccessPermissionException', 'InsufficientEncryptionPolicyException', 'InsufficientS3BucketPolicyException', 'InsufficientSnsTopicPolicyException', 'InvalidCloudWatchLogsLogGroupArnException', 'InvalidCloudWatchLogsRoleArnException', 'InvalidEventSelectorsException', 'InvalidHomeRegionException', 'InvalidKmsKeyIdException', 'InvalidLookupAttributesException', 'InvalidMaxResultsException', 'InvalidNextTokenException', 'InvalidParameterCombinationException', 'InvalidS3BucketNameException', 'InvalidS3PrefixException', 'InvalidSnsTopicNameException', 'InvalidTagParameterException', 'InvalidTimeRangeException', 'InvalidTokenException', 'InvalidTrailNameException', 'KmsException', 'KmsKeyDisabledException', 'KmsKeyNotFoundException', 'MaximumNumberOfTrailsExceededException', 'NotOrganizationMasterAccountException', 'OperationNotPermittedException', 'OrganizationNotInAllFeaturesModeException', 'OrganizationsNotInUseException', 'ResourceNotFoundException', 'ResourceTypeNotSupportedException', 'S3BucketDoesNotExistException', 'TagsLimitExceededException', 'TrailAlreadyExistsException', 'TrailNotFoundException', 'TrailNotProvidedException', 'UnsupportedOperationException'],
 'cloudwatch': ['InvalidParameterInput', 'ResourceNotFound', 'InternalServiceError', 'InvalidFormat', 'InvalidNextToken', 'InvalidParameterCombination', 'InvalidParameterValue', 'LimitExceeded', 'MissingParameter'],
 'codebuild': ['AccountLimitExceededException', 'InvalidInputException', 'OAuthProviderException', 'ResourceAlreadyExistsException', 'ResourceNotFoundException'],
 'config': ['InsufficientDeliveryPolicyException', 'InsufficientPermissionsException', 'InvalidConfigurationRecorderNameException', 'InvalidDeliveryChannelNameException', 'InvalidLimitException', 'InvalidNextTokenException', 'InvalidParameterValueException', 'InvalidRecordingGroupException', 'InvalidResultTokenException', 'InvalidRoleException', 'InvalidS3KeyPrefixException', 'InvalidSNSTopicARNException', 'InvalidTimeRangeException', 'LastDeliveryChannelDeleteFailedException', 'LimitExceededException', 'MaxNumberOfConfigRulesExceededException', 'MaxNumberOfConfigurationRecordersExceededException', 'MaxNumberOfDeliveryChannelsExceededException', 'MaxNumberOfRetentionConfigurationsExceededException', 'NoAvailableConfigurationRecorderException', 'NoAvailableDeliveryChannelException', 'NoAvailableOrganizationException', 'NoRunningConfigurationRecorderException', 'NoSuchBucketException', 'NoSuchConfigRuleException', 'NoSuchConfigurationAggregatorException', 'NoSuchConfigurationRecorderException', 'NoSuchDeliveryChannelException', 'NoSuchRetentionConfigurationException', 'OrganizationAccessDeniedException', 'OrganizationAllFeaturesNotEnabledException', 'OversizedConfigurationItemException', 'ResourceInUseException', 'ResourceNotDiscoveredException', 'ValidationException'],
 'dynamodb': ['BackupInUseException', 'BackupNotFoundException', 'ConditionalCheckFailedException', 'ContinuousBackupsUnavailableException', 'GlobalTableAlreadyExistsException', 'GlobalTableNotFoundException', 'IdempotentParameterMismatchException', 'IndexNotFoundException', 'InternalServerError', 'InvalidRestoreTimeException', 'ItemCollectionSizeLimitExceededException', 'LimitExceededException', 'PointInTimeRecoveryUnavailableException', 'ProvisionedThroughputExceededException', 'ReplicaAlreadyExistsException', 'ReplicaNotFoundException', 'RequestLimitExceeded', 'ResourceInUseException', 'ResourceNotFoundException', 'TableAlreadyExistsException', 'TableInUseException', 'TableNotFoundException', 'TransactionCanceledException', 'TransactionConflictException', 'TransactionInProgressException'],
 'ec2': [],
 'ecr': ['EmptyUploadException', 'ImageAlreadyExistsException', 'ImageNotFoundException', 'InvalidLayerException', 'InvalidLayerPartException', 'InvalidParameterException', 'InvalidTagParameterException', 'LayerAlreadyExistsException', 'LayerInaccessibleException', 'LayerPartTooSmallException', 'LayersNotFoundException', 'LifecyclePolicyNotFoundException', 'LifecyclePolicyPreviewInProgressException', 'LifecyclePolicyPreviewNotFoundException', 'LimitExceededException', 'RepositoryAlreadyExistsException', 'RepositoryNotEmptyException', 'RepositoryNotFoundException', 'RepositoryPolicyNotFoundException', 'ServerException', 'TooManyTagsException', 'UploadNotFoundException'],
 'ecs': ['AccessDeniedException', 'AttributeLimitExceededException', 'BlockedException', 'ClientException', 'ClusterContainsContainerInstancesException', 'ClusterContainsServicesException', 'ClusterContainsTasksException', 'ClusterNotFoundException', 'InvalidParameterException', 'MissingVersionException', 'NoUpdateAvailableException', 'PlatformTaskDefinitionIncompatibilityException', 'PlatformUnknownException', 'ResourceNotFoundException', 'ServerException', 'ServiceNotActiveException', 'ServiceNotFoundException', 'TargetNotFoundException', 'UnsupportedFeatureException', 'UpdateInProgressException'],
 'efs': ['BadRequest', 'DependencyTimeout', 'FileSystemAlreadyExists', 'FileSystemInUse', 'FileSystemLimitExceeded', 'FileSystemNotFound', 'IncorrectFileSystemLifeCycleState', 'IncorrectMountTargetState', 'InsufficientThroughputCapacity', 'InternalServerError', 'IpAddressInUse', 'MountTargetConflict', 'MountTargetNotFound', 'NetworkInterfaceLimitExceeded', 'NoFreeAddressesInSubnet', 'SecurityGroupLimitExceeded', 'SecurityGroupNotFound', 'SubnetNotFound', 'ThroughputLimitExceeded', 'TooManyRequests', 'UnsupportedAvailabilityZone'],
 'eks': ['ClientException', 'InvalidParameterException', 'InvalidRequestException', 'ResourceInUseException', 'ResourceLimitExceededException', 'ResourceNotFoundException', 'ServerException', 'ServiceUnavailableException', 'UnsupportedAvailabilityZoneException'],
 'elasticache': ['APICallRateForCustomerExceeded', 'AuthorizationAlreadyExists', 'AuthorizationNotFound', 'CacheClusterAlreadyExists', 'CacheClusterNotFound', 'CacheParameterGroupAlreadyExists', 'CacheParameterGroupNotFound', 'CacheParameterGroupQuotaExceeded', 'CacheSecurityGroupAlreadyExists', 'CacheSecurityGroupNotFound', 'QuotaExceeded.CacheSecurityGroup', 'CacheSubnetGroupAlreadyExists', 'CacheSubnetGroupInUse', 'CacheSubnetGroupNotFoundFault', 'CacheSubnetGroupQuotaExceeded', 'CacheSubnetQuotaExceededFault', 'ClusterQuotaForCustomerExceeded', 'InsufficientCacheClusterCapacity', 'InvalidARN', 'InvalidCacheClusterState', 'InvalidCacheParameterGroupState', 'InvalidCacheSecurityGroupState', 'InvalidParameterCombination', 'InvalidParameterValue', 'InvalidReplicationGroupState', 'InvalidSnapshotState', 'InvalidSubnet', 'InvalidVPCNetworkStateFault', 'NoOperationFault', 'NodeGroupNotFoundFault', 'NodeGroupsPerReplicationGroupQuotaExceeded', 'NodeQuotaForClusterExceeded', 'NodeQuotaForCustomerExceeded', 'ReplicationGroupAlreadyExists', 'ReplicationGroupNotFoundFault', 'ReservedCacheNodeAlreadyExists', 'ReservedCacheNodeNotFound', 'ReservedCacheNodeQuotaExceeded', 'ReservedCacheNodesOfferingNotFound', 'ServiceLinkedRoleNotFoundFault', 'SnapshotAlreadyExistsFault', 'SnapshotFeatureNotSupportedFault', 'SnapshotNotFoundFault', 'SnapshotQuotaExceededFault', 'SubnetInUse', 'TagNotFound', 'TagQuotaPerResourceExceeded', 'TestFailoverNotAvailableFault'],
 'elasticbeanstalk': ['CodeBuildNotInServiceRegionException', 'ElasticBeanstalkServiceException', 'InsufficientPrivilegesException', 'InvalidRequestException', 'ManagedActionInvalidStateException', 'OperationInProgressFailure', 'PlatformVersionStillReferencedException', 'ResourceNotFoundException', 'ResourceTypeNotSupportedException', 'S3LocationNotInServiceRegionException', 'S3SubscriptionRequiredException', 'SourceBundleDeletionFailure', 'TooManyApplicationVersionsException', 'TooManyApplicationsException', 'TooManyBucketsException', 'TooManyConfigurationTemplatesException', 'TooManyEnvironmentsException', 'TooManyPlatformsException', 'TooManyTagsException'],
 'elb': ['LoadBalancerNotFound', 'CertificateNotFound', 'DependencyThrottle', 'DuplicateLoadBalancerName', 'DuplicateListener', 'DuplicatePolicyName', 'DuplicateTagKeys', 'InvalidConfigurationRequest', 'InvalidInstance', 'InvalidScheme', 'InvalidSecurityGroup', 'InvalidSubnet', 'ListenerNotFound', 'LoadBalancerAttributeNotFound', 'OperationNotPermitted', 'PolicyNotFound', 'PolicyTypeNotFound', 'SubnetNotFound', 'TooManyLoadBalancers', 'TooManyPolicies', 'TooManyTags', 'UnsupportedProtocol'],
 'emr': ['InternalServerError', 'InternalServerException', 'InvalidRequestException'],
 'es': ['BaseException', 'DisabledOperationException', 'InternalException', 'InvalidTypeException', 'LimitExceededException', 'ResourceAlreadyExistsException', 'ResourceNotFoundException', 'ValidationException'],
 'events': ['ConcurrentModificationException', 'InternalException', 'InvalidEventPatternException', 'LimitExceededException', 'ManagedRuleException', 'PolicyLengthExceededException', 'ResourceNotFoundException'],
 'firehose': ['ConcurrentModificationException', 'InvalidArgumentException', 'LimitExceededException', 'ResourceInUseException', 'ResourceNotFoundException', 'ServiceUnavailableException'],
 'glacier': ['InsufficientCapacityException', 'InvalidParameterValueException', 'LimitExceededException', 'MissingParameterValueException', 'PolicyEnforcedException', 'RequestTimeoutException', 'ResourceNotFoundException', 'ServiceUnavailableException'],
 'glue': ['AccessDeniedException', 'AlreadyExistsException', 'ConcurrentModificationException', 'ConcurrentRunsExceededException', 'ConditionCheckFailureException', 'CrawlerNotRunningException', 'CrawlerRunningException', 'CrawlerStoppingException', 'EntityNotFoundException', 'GlueEncryptionException', 'IdempotentParameterMismatchException', 'InternalServiceException', 'InvalidInputException', 'NoScheduleException', 'OperationTimeoutException', 'ResourceNumberLimitExceededException', 'SchedulerNotRunningException', 'SchedulerRunningException', 'SchedulerTransitioningException', 'ValidationException', 'VersionMismatchException'],
 'iam': ['ConcurrentModification', 'ReportExpired', 'ReportNotPresent', 'ReportInProgress', 'DeleteConflict', 'DuplicateCertificate', 'DuplicateSSHPublicKey', 'EntityAlreadyExists', 'EntityTemporarilyUnmodifiable', 'InvalidAuthenticationCode', 'InvalidCertificate', 'InvalidInput', 'InvalidPublicKey', 'InvalidUserType', 'KeyPairMismatch', 'LimitExceeded', 'MalformedCertificate', 'MalformedPolicyDocument', 'NoSuchEntity', 'PasswordPolicyViolation', 'PolicyEvaluation', 'PolicyNotAttachable', 'ServiceFailure', 'NotSupportedService', 'UnmodifiableEntity', 'UnrecognizedPublicKeyEncoding'],
 'kinesis': ['ExpiredIteratorException', 'ExpiredNextTokenException', 'InternalFailureException', 'InvalidArgumentException', 'KMSAccessDeniedException', 'KMSDisabledException', 'KMSInvalidStateException', 'KMSNotFoundException', 'KMSOptInRequired', 'KMSThrottlingException', 'LimitExceededException', 'ProvisionedThroughputExceededException', 'ResourceInUseException', 'ResourceNotFoundException'],
 'kms': ['AlreadyExistsException', 'CloudHsmClusterInUseException', 'CloudHsmClusterInvalidConfigurationException', 'CloudHsmClusterNotActiveException', 'CloudHsmClusterNotFoundException', 'CloudHsmClusterNotRelatedException', 'CustomKeyStoreHasCMKsException', 'CustomKeyStoreInvalidStateException', 'CustomKeyStoreNameInUseException', 'CustomKeyStoreNotFoundException', 'DependencyTimeoutException', 'DisabledException', 'ExpiredImportTokenException', 'IncorrectKeyMaterialException', 'IncorrectTrustAnchorException', 'InvalidAliasNameException', 'InvalidArnException', 'InvalidCiphertextException', 'InvalidGrantIdException', 'InvalidGrantTokenException', 'InvalidImportTokenException', 'InvalidKeyUsageException', 'InvalidMarkerException', 'KMSInternalException', 'KMSInvalidStateException', 'KeyUnavailableException', 'LimitExceededException', 'MalformedPolicyDocumentException', 'NotFoundException', 'TagException', 'UnsupportedOperationException'],
 'lambda': ['CodeStorageExceededException', 'EC2AccessDeniedException', 'EC2ThrottledException', 'EC2UnexpectedException', 'ENILimitReachedException', 'InvalidParameterValueException', 'InvalidRequestContentException', 'InvalidRuntimeException', 'InvalidSecurityGroupIDException', 'InvalidSubnetIDException', 'InvalidZipFileException', 'KMSAccessDeniedException', 'KMSDisabledException', 'KMSInvalidStateException', 'KMSNotFoundException', 'PolicyLengthExceededException', 'PreconditionFailedException', 'RequestTooLargeException', 'ResourceConflictException', 'ResourceInUseException', 'ResourceNotFoundException', 'ServiceException', 'SubnetIPAddressLimitReachedException', 'TooManyRequestsException', 'UnsupportedMediaTypeException'],
 'logs': ['DataAlreadyAcceptedException', 'InvalidOperationException', 'InvalidParameterException', 'InvalidSequenceTokenException', 'LimitExceededException', 'MalformedQueryException', 'OperationAbortedException', 'ResourceAlreadyExistsException', 'ResourceNotFoundException', 'ServiceUnavailableException', 'UnrecognizedClientException'],
 'neptune': ['AuthorizationNotFound', 'CertificateNotFound', 'DBClusterAlreadyExistsFault', 'DBClusterNotFoundFault', 'DBClusterParameterGroupNotFound', 'DBClusterQuotaExceededFault', 'DBClusterRoleAlreadyExists', 'DBClusterRoleNotFound', 'DBClusterRoleQuotaExceeded', 'DBClusterSnapshotAlreadyExistsFault', 'DBClusterSnapshotNotFoundFault', 'DBInstanceAlreadyExists', 'DBInstanceNotFound', 'DBParameterGroupAlreadyExists', 'DBParameterGroupNotFound', 'DBParameterGroupQuotaExceeded', 'DBSecurityGroupNotFound', 'DBSnapshotAlreadyExists', 'DBSnapshotNotFound', 'DBSubnetGroupAlreadyExists', 'DBSubnetGroupDoesNotCoverEnoughAZs', 'DBSubnetGroupNotFoundFault', 'DBSubnetGroupQuotaExceeded', 'DBSubnetQuotaExceededFault', 'DBUpgradeDependencyFailure', 'DomainNotFoundFault', 'EventSubscriptionQuotaExceeded', 'InstanceQuotaExceeded', 'InsufficientDBClusterCapacityFault', 'InsufficientDBInstanceCapacity', 'InsufficientStorageClusterCapacity', 'InvalidDBClusterSnapshotStateFault', 'InvalidDBClusterStateFault', 'InvalidDBInstanceState', 'InvalidDBParameterGroupState', 'InvalidDBSecurityGroupState', 'InvalidDBSnapshotState', 'InvalidDBSubnetGroupStateFault', 'InvalidDBSubnetStateFault', 'InvalidEventSubscriptionState', 'InvalidRestoreFault', 'InvalidSubnet', 'InvalidVPCNetworkStateFault', 'KMSKeyNotAccessibleFault', 'OptionGroupNotFoundFault', 'ProvisionedIopsNotAvailableInAZFault', 'ResourceNotFoundFault', 'SNSInvalidTopic', 'SNSNoAuthorization', 'SNSTopicArnNotFound', 'SharedSnapshotQuotaExceeded', 'SnapshotQuotaExceeded', 'SourceNotFound', 'StorageQuotaExceeded', 'StorageTypeNotSupported', 'SubnetAlreadyInUse', 'SubscriptionAlreadyExist', 'SubscriptionCategoryNotFound', 'SubscriptionNotFound'],
 'rds': ['AuthorizationAlreadyExists', 'AuthorizationNotFound', 'AuthorizationQuotaExceeded', 'BackupPolicyNotFoundFault', 'CertificateNotFound', 'DBClusterAlreadyExistsFault', 'DBClusterBacktrackNotFoundFault', 'DBClusterEndpointAlreadyExistsFault', 'DBClusterEndpointNotFoundFault', 'DBClusterEndpointQuotaExceededFault', 'DBClusterNotFoundFault', 'DBClusterParameterGroupNotFound', 'DBClusterQuotaExceededFault', 'DBClusterRoleAlreadyExists', 'DBClusterRoleNotFound', 'DBClusterRoleQuotaExceeded', 'DBClusterSnapshotAlreadyExistsFault', 'DBClusterSnapshotNotFoundFault', 'DBInstanceAlreadyExists', 'DBInstanceAutomatedBackupNotFound', 'DBInstanceAutomatedBackupQuotaExceeded', 'DBInstanceNotFound', 'DBInstanceRoleAlreadyExists', 'DBInstanceRoleNotFound', 'DBInstanceRoleQuotaExceeded', 'DBLogFileNotFoundFault', 'DBParameterGroupAlreadyExists', 'DBParameterGroupNotFound', 'DBParameterGroupQuotaExceeded', 'DBSecurityGroupAlreadyExists', 'DBSecurityGroupNotFound', 'DBSecurityGroupNotSupported', 'QuotaExceeded.DBSecurityGroup', 'DBSnapshotAlreadyExists', 'DBSnapshotNotFound', 'DBSubnetGroupAlreadyExists', 'DBSubnetGroupDoesNotCoverEnoughAZs', 'DBSubnetGroupNotAllowedFault', 'DBSubnetGroupNotFoundFault', 'DBSubnetGroupQuotaExceeded', 'DBSubnetQuotaExceededFault', 'DBUpgradeDependencyFailure', 'DomainNotFoundFault', 'EventSubscriptionQuotaExceeded', 'GlobalClusterAlreadyExistsFault', 'GlobalClusterNotFoundFault', 'GlobalClusterQuotaExceededFault', 'InstanceQuotaExceeded', 'InsufficientDBClusterCapacityFault', 'InsufficientDBInstanceCapacity', 'InsufficientStorageClusterCapacity', 'InvalidDBClusterCapacityFault', 'InvalidDBClusterEndpointStateFault', 'InvalidDBClusterSnapshotStateFault', 'InvalidDBClusterStateFault', 'InvalidDBInstanceAutomatedBackupState', 'InvalidDBInstanceState', 'InvalidDBParameterGroupState', 'InvalidDBSecurityGroupState', 'InvalidDBSnapshotState', 'InvalidDBSubnetGroupFault', 'InvalidDBSubnetGroupStateFault', 'InvalidDBSubnetStateFault', 'InvalidEventSubscriptionState', 'InvalidGlobalClusterStateFault', 'InvalidOptionGroupStateFault', 'InvalidRestoreFault', 'InvalidS3BucketFault', 'InvalidSubnet', 'InvalidVPCNetworkStateFault', 'KMSKeyNotAccessibleFault', 'OptionGroupAlreadyExistsFault', 'OptionGroupNotFoundFault', 'OptionGroupQuotaExceededFault', 'PointInTimeRestoreNotEnabled', 'ProvisionedIopsNotAvailableInAZFault', 'ReservedDBInstanceAlreadyExists', 'ReservedDBInstanceNotFound', 'ReservedDBInstanceQuotaExceeded', 'ReservedDBInstancesOfferingNotFound', 'ResourceNotFoundFault', 'SNSInvalidTopic', 'SNSNoAuthorization', 'SNSTopicArnNotFound', 'SharedSnapshotQuotaExceeded', 'SnapshotQuotaExceeded', 'SourceNotFound', 'StorageQuotaExceeded', 'StorageTypeNotSupported', 'SubnetAlreadyInUse', 'SubscriptionAlreadyExist', 'SubscriptionCategoryNotFound', 'SubscriptionNotFound'],
 'route53': ['ConcurrentModification', 'ConflictingDomainExists', 'ConflictingTypes', 'DelegationSetAlreadyCreated', 'DelegationSetAlreadyReusable', 'DelegationSetInUse', 'DelegationSetNotAvailable', 'DelegationSetNotReusable', 'HealthCheckAlreadyExists', 'HealthCheckInUse', 'HealthCheckVersionMismatch', 'HostedZoneAlreadyExists', 'HostedZoneNotEmpty', 'HostedZoneNotFound', 'HostedZoneNotPrivate', 'IncompatibleVersion', 'InsufficientCloudWatchLogsResourcePolicy', 'InvalidArgument', 'InvalidChangeBatch', 'InvalidDomainName', 'InvalidInput', 'InvalidPaginationToken', 'InvalidTrafficPolicyDocument', 'InvalidVPCId', 'LastVPCAssociation', 'LimitsExceeded', 'NoSuchChange', 'NoSuchCloudWatchLogsLogGroup', 'NoSuchDelegationSet', 'NoSuchGeoLocation', 'NoSuchHealthCheck', 'NoSuchHostedZone', 'NoSuchQueryLoggingConfig', 'NoSuchTrafficPolicy', 'NoSuchTrafficPolicyInstance', 'NotAuthorizedException', 'PriorRequestNotComplete', 'PublicZoneVPCAssociation', 'QueryLoggingConfigAlreadyExists', 'ThrottlingException', 'TooManyHealthChecks', 'TooManyHostedZones', 'TooManyTrafficPolicies', 'TooManyTrafficPolicyInstances', 'TooManyTrafficPolicyVersionsForCurrentPolicy', 'TooManyVPCAssociationAuthorizations', 'TrafficPolicyAlreadyExists', 'TrafficPolicyInUse', 'TrafficPolicyInstanceAlreadyExists', 'VPCAssociationAuthorizationNotFound', 'VPCAssociationNotFound'],
 's3': ['BucketAlreadyExists', 'BucketAlreadyOwnedByYou', 'NoSuchBucket', 'NoSuchKey', 'NoSuchUpload', 'ObjectAlreadyInActiveTierError', 'ObjectNotInActiveTierError'],
 'sagemaker': ['ResourceInUse', 'ResourceLimitExceeded', 'ResourceNotFound'],
 'secretsmanager': ['DecryptionFailure', 'EncryptionFailure', 'InternalServiceError', 'InvalidNextTokenException', 'InvalidParameterException', 'InvalidRequestException', 'LimitExceededException', 'MalformedPolicyDocumentException', 'PreconditionNotMetException', 'ResourceExistsException', 'ResourceNotFoundException'],
 'ses': ['AccountSendingPausedException', 'AlreadyExists', 'CannotDelete', 'ConfigurationSetAlreadyExists', 'ConfigurationSetDoesNotExist', 'ConfigurationSetSendingPausedException', 'CustomVerificationEmailInvalidContent', 'CustomVerificationEmailTemplateAlreadyExists', 'CustomVerificationEmailTemplateDoesNotExist', 'EventDestinationAlreadyExists', 'EventDestinationDoesNotExist', 'FromEmailAddressNotVerified', 'InvalidCloudWatchDestination', 'InvalidConfigurationSet', 'InvalidFirehoseDestination', 'InvalidLambdaFunction', 'InvalidPolicy', 'InvalidRenderingParameter', 'InvalidS3Configuration', 'InvalidSNSDestination', 'InvalidSnsTopic', 'InvalidTemplate', 'InvalidTrackingOptions', 'LimitExceeded', 'MailFromDomainNotVerifiedException', 'MessageRejected', 'MissingRenderingAttribute', 'ProductionAccessNotGranted', 'RuleDoesNotExist', 'RuleSetDoesNotExist', 'TemplateDoesNotExist', 'TrackingOptionsAlreadyExistsException', 'TrackingOptionsDoesNotExistException'],
 'sns': ['AuthorizationError', 'EndpointDisabled', 'FilterPolicyLimitExceeded', 'InternalError', 'InvalidParameter', 'ParameterValueInvalid', 'InvalidSecurity', 'KMSAccessDenied', 'KMSDisabled', 'KMSInvalidState', 'KMSNotFound', 'KMSOptInRequired', 'KMSThrottling', 'NotFound', 'PlatformApplicationDisabled', 'SubscriptionLimitExceeded', 'Throttled', 'TopicLimitExceeded'],
 'sqs': ['AWS.SimpleQueueService.BatchEntryIdsNotDistinct', 'AWS.SimpleQueueService.BatchRequestTooLong', 'AWS.SimpleQueueService.EmptyBatchRequest', 'InvalidAttributeName', 'AWS.SimpleQueueService.InvalidBatchEntryId', 'InvalidIdFormat', 'InvalidMessageContents', 'AWS.SimpleQueueService.MessageNotInflight', 'OverLimit', 'AWS.SimpleQueueService.PurgeQueueInProgress', 'AWS.SimpleQueueService.QueueDeletedRecently', 'AWS.SimpleQueueService.NonExistentQueue', 'QueueAlreadyExists', 'ReceiptHandleIsInvalid', 'AWS.SimpleQueueService.TooManyEntriesInBatchRequest', 'AWS.SimpleQueueService.UnsupportedOperation'],
 'ssm': ['AlreadyExistsException', 'AssociatedInstances', 'AssociationAlreadyExists', 'AssociationDoesNotExist', 'AssociationExecutionDoesNotExist', 'AssociationLimitExceeded', 'AssociationVersionLimitExceeded', 'AutomationDefinitionNotFoundException', 'AutomationDefinitionVersionNotFoundException', 'AutomationExecutionLimitExceededException', 'AutomationExecutionNotFoundException', 'AutomationStepNotFoundException', 'ComplianceTypeCountLimitExceededException', 'CustomSchemaCountLimitExceededException', 'DocumentAlreadyExists', 'DocumentLimitExceeded', 'DocumentPermissionLimit', 'DocumentVersionLimitExceeded', 'DoesNotExistException', 'DuplicateDocumentContent', 'DuplicateDocumentVersionName', 'DuplicateInstanceId', 'FeatureNotAvailableException', 'HierarchyLevelLimitExceededException', 'HierarchyTypeMismatchException', 'IdempotentParameterMismatch', 'InternalServerError', 'InvalidActivation', 'InvalidActivationId', 'InvalidAggregatorException', 'InvalidAllowedPatternException', 'InvalidAssociation', 'InvalidAssociationVersion', 'InvalidAutomationExecutionParametersException', 'InvalidAutomationSignalException', 'InvalidAutomationStatusUpdateException', 'InvalidCommandId', 'InvalidDeleteInventoryParametersException', 'InvalidDeletionIdException', 'InvalidDocument', 'InvalidDocumentContent', 'InvalidDocumentOperation', 'InvalidDocumentSchemaVersion', 'InvalidDocumentVersion', 'InvalidFilter', 'InvalidFilterKey', 'InvalidFilterOption', 'InvalidFilterValue', 'InvalidInstanceId', 'InvalidInstanceInformationFilterValue', 'InvalidInventoryGroupException', 'InvalidInventoryItemContextException', 'InvalidInventoryRequestException', 'InvalidItemContentException', 'InvalidKeyId', 'InvalidNextToken', 'InvalidNotificationConfig', 'InvalidOptionException', 'InvalidOutputFolder', 'InvalidOutputLocation', 'InvalidParameters', 'InvalidPermissionType', 'InvalidPluginName', 'InvalidResourceId', 'InvalidResourceType', 'InvalidResultAttributeException', 'InvalidRole', 'InvalidSchedule', 'InvalidTarget', 'InvalidTypeNameException', 'InvalidUpdate', 'InvocationDoesNotExist', 'ItemContentMismatchException', 'ItemSizeLimitExceededException', 'MaxDocumentSizeExceeded', 'ParameterAlreadyExists', 'ParameterLimitExceeded', 'ParameterMaxVersionLimitExceeded', 'ParameterNotFound', 'ParameterPatternMismatchException', 'ParameterVersionLabelLimitExceeded', 'ParameterVersionNotFound', 'ResourceDataSyncAlreadyExistsException', 'ResourceDataSyncCountExceededException', 'ResourceDataSyncInvalidConfigurationException', 'ResourceDataSyncNotFoundException', 'ResourceInUseException', 'ResourceLimitExceededException', 'StatusUnchanged', 'SubTypeCountLimitExceededException', 'TargetInUseException', 'TargetNotConnected', 'TooManyTagsError', 'TooManyUpdates', 'TotalSizeLimitExceededException', 'UnsupportedInventoryItemContextException', 'UnsupportedInventorySchemaVersionException', 'UnsupportedOperatingSystem', 'UnsupportedParameterType', 'UnsupportedPlatformType'],
 'stepfunctions': ['ActivityDoesNotExist', 'ActivityLimitExceeded', 'ActivityWorkerLimitExceeded', 'ExecutionAlreadyExists', 'ExecutionDoesNotExist', 'ExecutionLimitExceeded', 'InvalidArn', 'InvalidDefinition', 'InvalidExecutionInput', 'InvalidName', 'InvalidOutput', 'InvalidToken', 'MissingRequiredParameter', 'ResourceNotFound', 'StateMachineAlreadyExists', 'StateMachineDeleting', 'StateMachineDoesNotExist', 'StateMachineLimitExceeded', 'TaskDoesNotExist', 'TaskTimedOut', 'TooManyTags'],
 'sts': ['ExpiredTokenException', 'IDPCommunicationError', 'IDPRejectedClaim', 'InvalidAuthorizationMessageException', 'InvalidIdentityToken', 'MalformedPolicyDocument', 'PackedPolicyTooLarge', 'RegionDisabledException'],
 'xray': ['InvalidRequestException', 'RuleLimitExceededException', 'ThrottledException']}

Lub porównanie nazwy klasy, np

except ClientError as e:
    if 'EntityAlreadyExistsException' == e.__class__.__name__:
        # handle specific error

Ponieważ są one tworzone dynamicznie, nigdy nie można zaimportować klasy i złapać jej za pomocą prawdziwego języka Python.

Jeśli wywołujesz API sign_up (AWS Cognito) za pomocą Python3, możesz użyć następującego kodu.

def registerUser(userObj):
    ''' Registers the user to AWS Cognito.
    '''

    # Mobile number is not a mandatory field. 
    if(len(userObj['user_mob_no']) == 0):
        mobilenumber = ''
    else:
        mobilenumber = userObj['user_country_code']+userObj['user_mob_no']

    secretKey = bytes(settings.SOCIAL_AUTH_COGNITO_SECRET, 'latin-1')
    clientId = settings.SOCIAL_AUTH_COGNITO_KEY 

    digest = hmac.new(secretKey,
                msg=(userObj['user_name'] + clientId).encode('utf-8'),
                digestmod=hashlib.sha256
                ).digest()
    signature = base64.b64encode(digest).decode()

    client = boto3.client('cognito-idp', region_name='eu-west-1' ) 

    try:
        response = client.sign_up(
                    ClientId=clientId,
                    Username=userObj['user_name'],
                    Password=userObj['password1'],
                    SecretHash=signature,
                    UserAttributes=[
                        {
                            'Name': 'given_name',
                            'Value': userObj['given_name']
                        },
                        {
                            'Name': 'family_name',
                            'Value': userObj['family_name']
                        },
                        {
                            'Name': 'email',
                            'Value': userObj['user_email']
                        },
                        {
                            'Name': 'phone_number',
                            'Value': mobilenumber
                        }
                    ],
                    ValidationData=[
                        {
                            'Name': 'email',
                            'Value': userObj['user_email']
                        },
                    ]
                    ,
                    AnalyticsMetadata={
                        'AnalyticsEndpointId': 'string'
                    },
                    UserContextData={
                        'EncodedData': 'string'
                    }
                )
    except ClientError as error:
        return {"errorcode": error.response['Error']['Code'],
            "errormessage" : error.response['Error']['Message'] }
    except Exception as e:
        return {"errorcode": "Something went wrong. Try later or contact the admin" }
    return {"success": "User registered successfully. "}

error.response [„Error”] [„Code”] będzie InvalidPasswordException, UsernameExistsException itp. Tak więc w funkcji głównej lub w miejscu, w którym wywołujesz funkcję, możesz napisać logikę, aby przekazać użytkownikowi znaczącą wiadomość.

Przykład odpowiedzi (error.response):

{
  "Error": {
    "Message": "Password did not conform with policy: Password must have symbol characters",
    "Code": "InvalidPasswordException"
  },
  "ResponseMetadata": {
    "RequestId": "c8a591d5-8c51-4af9-8fad-b38b270c3ca2",
    "HTTPStatusCode": 400,
    "HTTPHeaders": {
      "date": "Wed, 17 Jul 2019 09:38:32 GMT",
      "content-type": "application/x-amz-json-1.1",
      "content-length": "124",
      "connection": "keep-alive",
      "x-amzn-requestid": "c8a591d5-8c51-4af9-8fad-b38b270c3ca2",
      "x-amzn-errortype": "InvalidPasswordException:",
      "x-amzn-errormessage": "Password did not conform with policy: Password must have symbol characters"
    },
    "RetryAttempts": 0
  }
}

Więcej informacji: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/cognito-idp.html#CognitoIdentityProvider.Client.sign_up

Jeśli masz do czynienia z prawdopodobnie nieprzyjaznym logsklientem ( CloudWatch Logsput-log-events ), to właśnie musiałem zrobić, aby poprawnie wychwycić wyjątki klienta Boto3:

try:
    ### Boto3 client code here...

except boto_exceptions.ClientError as error:
    Log.warning("Catched client error code %s",
                error.response['Error']['Code'])

    if error.response['Error']['Code'] in ["DataAlreadyAcceptedException",
                                           "InvalidSequenceTokenException"]:
        Log.debug(
            "Fetching sequence_token from boto error response['Error']['Message'] %s",
            error.response["Error"]["Message"])
        # NOTE: apparently there's no sequenceToken attribute in the response so we have
        # to parse response["Error"]["Message"] string
        sequence_token = error.response["Error"]["Message"].split(":")[-1].strip(" ")
        Log.debug("Setting sequence_token to %s", sequence_token)

Działa to zarówno przy pierwszej próbie (z pustym LogStream), jak i kolejnych.

Po aktualizacji @ armod o dodawaniu wyjątków bezpośrednio do clientobiektów. Pokażę, jak możesz zobaczyć wszystkie wyjątki zdefiniowane dla twojej klasy klienta.

Wyjątki są generowane dynamicznie podczas tworzenia klienta za pomocą session.create_client()lub boto3.client(). Wewnętrznie wywołuje metodę botocore.errorfactory.ClientExceptionsFactory._create_client_exceptions()i wypełnia client.exceptionspole zbudowanymi klasami wyjątków.

Wszystkie nazwy klas są dostępne w client.exceptions._code_to_exceptionsłowniku, więc możesz wyświetlić listę wszystkich typów za pomocą następującego fragmentu:

client = boto3.client('s3')

for ex_code in client.exceptions._code_to_exception:
    print(ex_code)

Mam nadzieję, że to pomoże.

Musisz coś zrobić, gdy problem nie zostanie rozwiązany. W tej chwili zwracasz faktyczny wyjątek. Na przykład, jeśli nie jest to problem, że użytkownik już istnieje i chcesz użyć go jako funkcji get_or_create, być może poradzisz sobie z tym, zwracając istniejący obiekt użytkownika.

try:
    user = iam_conn.create_user(UserName=username)
    return user
except botocore.exceptions.ClientError as e:

    #this exception could actually be other things other than exists, so you want to evaluate it further in your real code.
    if e.message.startswith(
        'enough of the exception message to identify it as the one you want')

        print('that user already exists.')
        user = iam_conn.get_user(UserName=username)
        return user

    elif e.message.some_other_condition:

         #something else
    else:
         #unhandled ClientError
         raise(e)
except SomeOtherExceptionTypeYouCareAbout as e:
    #handle it

# any unhandled exception will raise here at this point.
# if you want a general handler

except Exception as e:
    #handle it.

To powiedziawszy, być może jest to problem dla twojej aplikacji, w którym to przypadku chcesz umieścić moduł obsługi wyjątków wokół kodu, który wywołał twoją funkcję użytkownika, i pozwól funkcji wywołującej określić, jak sobie z tym poradzić, na przykład pytając użytkownik, aby wprowadzić inną nazwę użytkownika lub cokolwiek, co ma sens dla Twojej aplikacji.