我试图弄清楚如何使用boto3进行正确的错误处理。

我正在尝试创建一个IAM用户:

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

当调用create_user成功时,我得到一个整洁的对象,其中包含API调用的http状态代码和新创建用户的数据。

例子:

{'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'
          }
}

这很有效。但是当这个失败时(比如如果用户已经存在),我只得到一个botocore.exceptions.ClientError类型的对象,其中只有文本告诉我哪里出错了。

例子: ClientError('调用CreateUser操作时发生错误(EntityAlreadyExists):省略名称的用户已经存在。')

这(AFAIK)使得错误处理非常困难,因为我不能只是打开结果的http状态代码(409用户已经存在根据AWS API文档的IAM)。这让我觉得我一定是做错了什么。最优的方法是boto3永远不抛出异常,但juts总是返回一个反映API调用如何进行的对象。

有没有人能在这个问题上给我一些启发,或者给我指出正确的方向?


当前回答

当它不能处理问题时,你需要做些什么。现在您返回的是实际的异常。 例如,如果用户已经存在而你想使用它作为get_or_create函数,也许你可以通过返回现有的用户对象来处理这个问题。

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.

也就是说,这可能是你的应用程序的问题,在这种情况下,你想要在调用create user函数的代码周围放置异常处理程序并让调用函数决定如何处理它,例如,通过要求用户输入另一个用户名,或任何对你的应用程序有意义的东西。

其他回答

当它不能处理问题时,你需要做些什么。现在您返回的是实际的异常。 例如,如果用户已经存在而你想使用它作为get_or_create函数,也许你可以通过返回现有的用户对象来处理这个问题。

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.

也就是说,这可能是你的应用程序的问题,在这种情况下,你想要在调用create user函数的代码周围放置异常处理程序并让调用函数决定如何处理它,例如,通过要求用户输入另一个用户名,或任何对你的应用程序有意义的东西。

正如其他人已经提到的,您可以使用服务客户端(service_client.exceptions.<ExceptionClass>)或资源(service_resource. metadata .client.exceptions.<ExceptionClass>)捕获某些错误,但是没有很好的文档(以及哪些异常属于哪些客户端)。因此,以下是如何在撰写本文时(2020年1月)获得欧盟(爱尔兰)地区(EU -west-1)的完整地图:

import boto3, pprint

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

下面是这个相当大的文档的一个子集:

{'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']}

只需要一个导入。 不需要if语句。 按预期使用客户端内置异常。

Ex:

from boto3 import client

cli = client('iam')
try:
    cli.create_user(
        UserName = 'Brian'
    )
except cli.exceptions.EntityAlreadyExistsException:
    pass

CloudWatch示例:

cli = client('logs')
try:
    cli.create_log_group(
        logGroupName = 'MyLogGroup'
    )
except cli.exceptions.ResourceAlreadyExistsException:
    pass

如果你不得不处理不友好的日志客户端(CloudWatch logs put-log-events),这是我必须做的,以正确捕获Boto3客户端异常:

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)

这在第一次尝试(空LogStream)和后续尝试时都有效。

使用异常中包含的响应。这里有一个例子:

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)

异常中的响应字典将包含以下内容:

(“错误”)(“代码”)。'EntityAlreadyExists'或'ValidationError' [' responsemetdata ']['HTTPStatusCode']例:400 [“ResponseMetadata”][' RequestId ']。“d2b06652 - 88 - d7 - 11 - e5 - 99 - d0 - 812348583 - a35” (“错误”)(“信息”)。"发生错误(EntityAlreadyExists)…" ['错误']['类型']。“发送”

有关更多信息,请参阅:

Boto3错误处理 Botocore错误处理

(更新:2018-03-07)

AWS Python SDK已经开始公开客户端上的服务异常(虽然不是资源上的异常),你可以显式地捕获这些异常,所以现在可以像这样编写代码:

import botocore
import boto3

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 botocore.exceptions.ParamValidationError as e:
    print("Parameter validation error: %s" % e)
except botocore.exceptions.ClientError as e:
    print("Unexpected error: %s" % e)

不幸的是,目前没有关于这些错误/异常的文档,但你可以得到一个核心错误列表,如下所示:

import botocore
import boto3
[e for e in dir(botocore.exceptions) if e.endswith('Error')]

注意,必须同时导入botocore和boto3。如果你只导入botocore,你会发现botocore没有名为exceptions的属性。这是因为异常被boto3动态地填充到botocore中。

您可以获得以下特定于服务的异常列表(根据需要将iam替换为相关的服务):

import boto3
iam = boto3.client('iam')
[e for e in dir(iam.exceptions) if e.endswith('Exception')]

(更新:2021-09-07)

除了前面提到的客户端异常方法之外,还有一个名为aws-error-utils的第三方帮助包。