本章将详细介绍执行和调用Lambda函数的过程及其中涉及的步骤.
AWS Lambda执行模型
AWS执行取决于为AWS Lambda Function添加的配置详细信息.创建函数时，会有内存和时间分配，用于执行AWS Lambda函数.
借助配置详细信息，AWS Lambda可创建执行上下文.执行上下文是一个临时运行时环境，可以使用任何外部依赖项(如数据库连接，http端点，第三方库等)(如果有).
调用AWS Lambda函数时第一次或者如果更新lambda函数，由于执行上下文设置，添加的延迟很少.但是，与第一次调用相比，后续调用更快.如果在较短的时间内调用Lambda函数，AWS Lambda会再次尝试重用执行上下文.
执行上下文的重用具有以下含义和减号;
如果为执行Lambda完成了任何数据库连接，则保持连接以便重用.因此，Lambda代码必须首先检查连接 - 如果存在并重新使用;否则我们必须重新建立新连接.
执行上下文在/tmp 目录中保留500MB的磁盘空间.所需数据缓存在此目录中.您可以在代码中进行额外检查以查看数据是否存在.
如果回调或某些后台进程在Lambda函数为调用时，执行将在再次调用lambda函数时启动.如果你不需要这样的事情，请确保你的进程在函数执行完成后正确结束.
你应该使用执行上下文和存储在tmp目录中的数据.您必须在代码中添加必要的检查，以查看在创建新的数据之前是否存在所需的数据.这将节省执行期间的时间并使其更快.
调用AWS Lambda函数
我们可以使用 aws cli手动调用AWS 的.我们已经了解了如何使用 cli 创建和部署AWS Lambda.在这里，我们将首先使用 aws cli 创建一个函数并调用它.
使用AWS CLI创建AWS Lambda函数
您可以使用以下命令使用 aws cli :
命令
$ b创建AWS Lambda函数$ b
create-function --function-name--runtime --role --handler [--code ] [--description ] [--timeout ] [--memory-size ] [--environment ] [--kms-key-arn ] [--tags ] [--zip-file ] [--cli-input-json ]
带值的命令
aws lambda create-function --function-name "lambdainvoke" --runtime "nodejs8.10" --role "arn:aws:iam::625297745038:role/lambdaapipolicy" --handler "index.handler" --timeout 5 --memory-size 256 --zip-file "fileb://C:\nodeproject\index.zip"
输出如下所示 :
在AWS控制台中创建的功能如下所示 :
现在，您可以使用以下命令调用该函数:调用
--function-name[--invocation-type ][--log-type ][--client-context ][--payload ][--qualifier ]outfile
选项
- function-name : 指定要调用的函数的名称.
- 调用类型(字符串) : 默认情况下，invokation类型为 requestResponse则的.可用于invokation类型的值是 RequestResponse，Event 和 DryRun .
事件调用类型用于异步响应.
要验证Lambda函数时要使用DryRun无需执行它.
- log-type : 它将尾巴如果调用类型是RequestResponse.它给出了最后4KB base64编码的日志数据.可能的值为尾部和无.
- 客户端上下文&减号; 您可以传递客户端Lambda函数的具体细节. clientcontext必须是json格式和base64编码.最大文件大小为3583字节.
- 有效负载&减去; json格式输入到lambda函数.
- 限定符和减号; 您可以指定Lambda函数版本或别名.如果传递函数版本，则api将使用限定函数arn来调用Lambda函数.如果指定了别名，则api使用别名ARN来调用Lambda函数.
outfile : 这是保存内容的文件名.
带值的命令
aws lambda invoke --function-name "lambdainvoke" --log-type Tail C:\nodeproject\outputfile.txt
您可以使用payload选项以json格式向lambda函数发送虚拟事件，如下所示./p>
相关的AWS Lambda代码如下 :
exports.handler = async (event, callback) => { console.log("Hello => "+ event.name); console.log("Address =>"+ event.addr); callback(null, 'Hello '+event.name +" and address is "+ event.addr);};请注意，在代码中，我们有控制台 event.name 和 event.addr .现在，让我们在aws cli中使用payload选项来发送带有名称和地址的事件，如下所示 :
aws lambda invoke --function-name "lambdainvoke" --log-type Tail --payload file://C:\clioutput\input.txt C:\clioutput\outputfile.txt
Thenpayload将输入作为文件路径，其中json输入如图所示 :
{"name":"Roy Singh", "addr":"Mumbai"}相应的输出如下所示 :
输出存储在文件 C:\ clioutput \ output.txt 如下 :
"Hello Roy Singh and address is Mumbai"
示例事件
您可以通过传递示例事件来测试AWS Lambda函数.本节提供了AWS Services的一些示例事件.您可以使用 invoke 命令在使用任何服务触发时测试输出.观察为相应的样本事件提供的代码低于 :
Amazon S3 Put Sample事件
{ "Records": [{ "eventVersion": "2.0", "eventTime": "1970-01-01T00:00:00.000Z", "requestParameters": { "SourceIPAddress": "127.0.0.1" }, "s3": { "configurationId": "testConfigRule", "object": { "eTag": "0123456789abcdef0123456789abcdef", "sequencer": "0A1B2C3D4E5F678901", "key": "HappyFace.jpg", "size": 1024 }, "bucket": { "arn": bucketarn, "name": "Sourcebucket", "ownerIdentity": { "principalId": "EXAMPLE" } }, "s3SchemaVersion": "1.0" }, "responseElements": { "x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH", "x-amz-request-id": "EXAMPLE123456789" }, "awsRegion": "us-east-1", "eventName": "ObjectCreated:Put", "userIdentity": { "principalId": "EXAMPLE" }, "eventSource": "aws:s3" }]}从s3 put事件中获取文件的详细信息，您可以使用以下命令 :
event.Records [0] .s3.object.key//将显示名称文件
要获取存储桶名称，您可以使用以下命令 :
event.Records [0] .s3.bucket.name//将给出桶的名称.
要查看EventName ，您可以使用以下命令 :
event.Records [0] .eventName//将显示事件名
Amazon S3删除示例事件
{ "Records": [{ "eventVersion": "2.0", "eventTime": "1970-01-01T00:00:00.000Z", "requestParameters": { "SourceIPAddress": "127.0.0.1" }, "s3": { "configurationId": "testConfigRule", "object": { "sequencer": "0A1B2C3D4E5F678901", "key": "HappyFace.jpg" }, "bucket": { "arn": bucketarn, "name": "Sourcebucket", "ownerIdentity": { "principalId": "EXAMPLE" } }, "s3SchemaVersion": "1.0" }, "responseElements": { "x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH", "x-amz-request-id": "EXAMPLE123456789" }, "awsRegion": "us-east-1", "eventName": "ObjectRemoved:Delete", "userIdentity": { "principalId": "EXAMPLE" }, "eventSource": "aws:s3" }]}Amazon DynamoDB
在DynamoDB表上进行更改时，Amazon DynamoDB可以是AWS Lambda上的事件.我们可以执行添加条目，更新和删除DynamodDB表中的记录等操作.
此处显示DynamoDB添加，插入和删除事件的示例事件 :
{ "Records": [{ "eventID": "1", "eventVersion": "1.0", "dynamodb": { "Keys": { "Id": { "N": "101" } }, "NewImage": { "Message": { "S": "New item!" }, "Id": { "N": "101" } }, "StreamViewType": "NEW_AND_OLD_IMAGES", "SequenceNumber": "111", "SizeBytes": 26 }, "awsRegion": "us-west-2", "eventName": "INSERT", "eventSourceARN": eventSourcearn, "eventSource": "aws:dynamodb" }, { "eventID": "2", "eventVersion": "1.0", "dynamodb": { "OldImage": { "Message": { "S": "New item!" }, "Id": { "N": "101" } }, "SequenceNumber": "222", "Keys": { "Id": { "N": "101" } }, "SizeBytes": 59, "NewImage": { "Message": { "S": "This item has changed" }, "Id": { "N": "101" } }, "StreamViewType": "NEW_AND_OLD_IMAGES" }, "awsRegion": "us-west-2", "eventName": "MODIFY", "eventSourceARN": Sourcearn, "eventSource": "aws:dynamodb" }, { "eventID": "3", "eventVersion": "1.0", "dynamodb": { "Keys": { "Id": { "N": "101" } }, "SizeBytes": 38, "SequenceNumber": "333", "OldImage": { "Message": { "S": "This item has changed" }, "Id": { "N": "101" } }, "StreamViewType": "NEW_AND_OLD_IMAGES" }, "awsRegion": "us-west-2", "eventName": "REMOVE", "eventSourceARN": Sourcearn, "eventSource": "aws:dynamodb" }]}亚马逊简单通知服务
AWS Lambda可以帮助您处理在简单通知中创建的通知服务(SNS).每当在SNS中发布消息时，可以使用SNS事件触发Lambda函数，该事件具有消息的详细信息.此消息可在Lambda函数内处理，并可根据要求进一步发送到其他服务.
输入消息后，SNS将触发Lambda函数.如果任何错误试图调用Lambda函数，SNS将重试最多三次调用lambda函数.
Amazon SNS示例事件
示例具有AWS Lambda函数中可用于执行进一步处理的所有详细信息的事件如下所示 :
{ "Records": [{ "EventVersion": "1.0", "EventSubscriptionArn": eventsubscriptionarn, "EventSource": "aws:sns", "Sns": { "SignatureVersion": "1", "Timestamp": "1970-01-01T00:00:00.000Z", "Signature": "EXAMPLE", "SigningCertUrl": "EXAMPLE", "MessageId": "95df01b4-ee98-5cb9-9903-4c221d41eb5e", "Message": "Hello from SNS!", "MessageAttributes": { "Test": { "Type": "String", "Value": "TestString" }, "TestBinary": { "Type": "Binary", "Value": "TestBinary" } }, "Type": "Notification", "UnsubscribeUrl": "EXAMPLE", "TopicArn": topicarn, "Subject": "TestInvoke" } }]}亚马逊简单邮件服务
亚马逊简单邮件服务可用于发送邮件和接收邮件.收到消息后，可以在简单邮件服务上调用AWS Lambda函数.
Amazon SES电子邮件接收示例事件
SES事件的详细信息在AWS Lambda中使用时显示在下面 :
{ "Records": [{ "eventVersion": "1.0", "ses": { "mail": { "commonHeaders": { "from": [ "Jane Doe " ], "to": [ "johndoe@Source.com" ], "returnPath": "janedoe@example.com", "messageId": "<0123456789Source.com>", "date": "Wed, 7 Oct 2015 12:34:56 -0700", "subject": "Test Subject" }, "example": "janedoe@example.com", "timestamp": "1970-01-01T00:00:00.000Z", "destination": [ "johndoe@example.com" ], "headers": [{ "name": "Return-Path", "value": "" }, { "name": "Received", "value": "from mailer.example.com (mailer.example.com [203.0.113.1]) by inbound-smtp.us-west-2.amazonaws.com with SMTP id o3vrnil0e2ic for johndoe@example.com; Wed, 07 Oct 2015 12:34:56 +0000 (UTC)" }, { "name": "DKIM-Signature", "value": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=example.com; s=example; h=mime-version:from:date:message-id:subject:to:content-type; bh=jX3F0bCAI7sIbkHyy3mLYO28ieDQz2R0P8HwQkklFj4=; b=sQwJ+LMe9RjkesGu+vqU56asvMhrLRRYrWCbV" }, { "name": "MIME-Version", "value": "1.0" }, { "name": "From", "value": "Jane Doe " }, { "name": "Date", "value": "Wed, 7 Oct 2015 12:34:56 -0700" }, { "name": "Message-ID", "value": "<0123456789example.com>" }, { "name": "Subject", "value": "Test Subject" }, { "name": "To", "value": "johndoe@example.com" }, { "name": "Content-Type", "value": "text/plain; charset=UTF-8" }], "headersTruncated": false, "messageId": "o3vrnil0e2ic28tr" }, "receipt": { "recipients": [ "johndoe@example.com" ], "timestamp": "1970-01-01T00:00:00.000Z", "spamVerdict": { "status": "PASS" }, "dkimVerdict": { "status": "PASS" }, "processingTimeMillis": 574, "action": { "type": "Lambda", "invocationType": "Event", "functionArn": "arn:aws:lambda:us-west-2:012345678912:function:example" }, "spfVerdict": { "status": "PASS" }, "virusVerdict": { "status": "PASS" } } }, "eventexample": "aws:ses" }]} Amazon Cloudwatch日志
可以使用 CloudWatch Logs从Amazon CloudWatch Logs触发AWS Lambda订阅的. CloudWatch Logs订阅包含有关日志的数据实时数据，可以在AWS Lambda内部进行处理和分析，也可以用于加载到其他系统.
Amazon CloudWatch日志示例事件
{ "awslogs": { "data": "H4sIAAAAAAAAAHWPwQqCQBCGX0Xm7EFtK+smZBEUgXoLCdMhFtKV3akI8d0bLYmibvPPN3wz00CJxmQnTO41whwW QRIctmEcB6sQbFC3CjW3XW8kxpOpP+OC22d1Wml1qZkQGtoMsScxaczKN3plG8zlaHIta5KqWsozoTYw3/djzwhpL wivWFGHGpAFe7DL68JlBUk+l7KSN7tCOEJ4M3/qOI49vMHj+zCKdlFqLaU2ZHV2a4Ct/an0/ivdX8oYc1UVX860fQ DQiMdxRQEAAA==" }}亚马逊API网关
可以在https url上调用AWS Lambda函数。 IT可以在GET，POST，PUT上完成。 调用https url时，也会触发AWS Lambda函数，并且可以在AWS Lambda中使用get / post传递给https的数据，以用于在DynamoDB中插入或发送邮件等。
API Gateway Proxy Request Event
{ "path": "/test/hello", "headers": { "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8", "Accept-Encoding": "gzip, deflate, lzma, sdch, br", "Accept-Language": "en-US,en;q=0.8", "CloudFront-Forwarded-Proto": "https", "CloudFront-Is-Desktop-Viewer": "true", "CloudFront-Is-Mobile-Viewer": "false", "CloudFront-Is-SmartTV-Viewer": "false", "CloudFront-Is-Tablet-Viewer": "false", "CloudFront-Viewer-Country": "US", "Host": "wt6mne2s9k.execute-api.us-west-2.amazonaws.com", "Upgrade-Insecure-Requests": "1", "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48", "Via": "1.1 fb7cca60f0ecd82ce07790c9c5eef16c.cloudfront.net (CloudFront)", "X-Amz-Cf-Id": "nBsWBOrSHMgnaROZJK1wGCZ9PcRcSpq_oSXZNQwQ10OTZL4cimZo3g==", "X-Forwarded-For": "192.168.100.1, 192.168.1.1", "X-Forwarded-Port": "443", "X-Forwarded-Proto": "https" }, "pathParameters": { "proxy": "hello" }, "requestContext": { "accountId": "123456789012", "reexampleId": "us4z18", "stage": "test", "requestId": "41b45ea3-70b5-11e6-b7bd-69b5aaebc7d9", "identity": { "cognitoIdentityPoolId": "", "accountId": "", "cognitoIdentityId": "", "caller": "", "apiKey": "", "exampleIp": "192.168.100.1", "cognitoAuthenticationType": "", "cognitoAuthenticationProvider": "", "userArn": "", "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48", "user": "" }, "reexamplePath": "/{proxy+}", "httpMethod": "GET", "apiId": "wt6mne2s9k" }, "reexample": "/{proxy+}", "httpMethod": "GET", "queryStringParameters": { "name": "me" }, "stageVariables": { "stageVarName": "stageVarValue" }}API Gateway Proxy Response Event
{ "statusCode": 200, "headers": { "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8", "Accept-Encoding": "gzip, deflate, lzma, sdch, br", "Accept-Language": "en-US,en;q=0.8", "CloudFront-Forwarded-Proto": "https", "CloudFront-Is-Desktop-Viewer": "true", "CloudFront-Is-Mobile-Viewer": "false", "CloudFront-Is-SmartTV-Viewer": "false", "CloudFront-Is-Tablet-Viewer": "false", "CloudFront-Viewer-Country": "US", "Host": "wt6mne2s9k.execute-api.us-west-2.amazonaws.com", "Upgrade-Insecure-Requests": "1", "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48", "Via": "1.1 fb7cca60f0ecd82ce07790c9c5eef16c.cloudfront.net (CloudFront)", "X-Amz-Cf-Id": "nBsWBOrSHMgnaROZJK1wGCZ9PcRcSpq_oSXZNQwQ10OTZL4cimZo3g==", "X-Forwarded-For": "192.168.100.1, 192.168.1.1", "X-Forwarded-Port": "443", "X-Forwarded-Proto": "https" }, "body": "Hello World"}