This example demonstrates how to setup a simple HTTP GET endpoint using Java. Once you ping it, it will reply with the current time.
Jackson is used to serialize objects to JSON.
- Wrapping an existing internal or external endpoint/service
It is required to build prior to deploying. You can build the deployment artifact using Gradle or Maven.
In order to build using Gradle simply run
gradle wrapper # to build the gradle wrapper jar
./gradlew build # to build the application jarThe expected result should be similar to:
Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details
:compileJava
:processResources
:classes
:jar
:assemble
:buildZip
:compileTestJava UP-TO-DATE
:processTestResources UP-TO-DATE
:testClasses UP-TO-DATE
:test UP-TO-DATE
:check UP-TO-DATE
:build
BUILD SUCCESSFUL
Total time: 8.195 secsIn order to build using Maven simply run
mvn packageNote: you can install Maven with
- sdkman using
sdk install maven(yes, use as default) sudo apt-get install mvnbrew install maven
If you use Maven to build, then in serverless.yml you have to replace
package:
artifact: build/distributions/aws-java-simple-http-endpoint.zipwith
package:
artifact: target/aws-java-simple-http-endpoint.jarbefore deploying.
After having built the deployment artifact using Gradle or Maven as described above you can deploy by simply running
serverless deployThe expected result should be similar to:
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
.....
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading service .zip file to S3...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
..............................
Serverless: Stack update finished...
Service Information
service: aws-java-simple-http-endpoint
stage: dev
region: us-east-1
api keys:
None
endpoints:
GET - https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/ping
functions:
aws-java-simple-http-endpoint-dev-currentTime: arn:aws:lambda:us-east-1:XXXXXXX:function:aws-java-simple-http-endpoint-dev-currentTime
You can now invoke the Lambda function directly and even see the resulting log via
serverless invoke --function currentTime --logThe expected result should be similar to:
{
"statusCode": 200,
"body": "{\"message\":\"Hello, the current time is Wed Jan 04 23:44:37 UTC 2017\"}",
"headers": {
"X-Powered-By": "AWS Lambda & Serverless",
"Content-Type": "application/json"
},
"isBase64Encoded": false
}
--------------------------------------------------------------------
START RequestId: XXXXXXX Version: $LATEST
2004 23:44:37 <XXXXXXX> INFO com.serverless.Handler:18 - received: {}
END RequestId: XXXXXXX
REPORT RequestId: XXXXXXX Duration: 0.51 ms Billed Duration: 100 ms Memory Size: 1024 MB Max Memory Used: 53 MBFinally you can send an HTTP request directly to the endpoint using a tool like curl
curl https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/pingThe expected result should be similar to:
{"message": "Hello, the current time is Wed Jan 04 23:44:37 UTC 2017"}% By default, AWS Lambda limits the total concurrent executions across all functions within a given region to 100. The default limit is a safety limit that protects you from costs due to potential runaway or recursive functions during initial development and testing. To increase this limit above the default, follow the steps in To request a limit increase for concurrent executions.
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