try! Serverless App with Swift

Transcript

1. try! Serverless App with Swift
   '19/03/19 try! Swift Pre Talks 2019
   

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2. YU TAWATA
   • Job: iOS Engineer at DMM.com
   • Twitter: yuta24
   • GitHub: yuta24
   

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3. Why Serverless App with Swift?
   • Custom Runtime for AWS Lambda
   • Can execute programs written in any programming
   languages.
   • Swift 5
   • Easier to bridge to python, compared with Swift4
   

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4. What's AWS Lambda Custom Runtime?
   • bootstrap
   • execute programs using request params and return the
   results as responses
   #!/bin/sh
   set -euo pipefail
   # Initialization - load function handler
   source $LAMBDA_TASK_ROOT/"$(echo $_HANDLER | cut -d. -f1).sh"
   # Processing
   while true
   do
   HEADERS="$(mktemp)"
   # Get an event
   EVENT_DATA=$(curl -sS -LD "$HEADERS" -X GET "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next")
   REQUEST_ID=$(grep -Fi Lambda-Runtime-Aws-Request-Id "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)
   # Execute the handler function from the script
   RESPONSE=$($(echo "$_HANDLER" | cut -d. -f2) "$EVENT_DATA")
   # Send the response
   curl -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$REQUEST_ID/response" -d "$RESPONSE"
   done
   

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5. Let's, try!
   

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6. How?
   1. Create table on AWS Dynamo DB.
   2. Create AWS Lambda function.
   3. Create sample project using SPM.
   4. Make executable file (Using Docker: Swift 5 on Ubuntu 16.04).
   5. Deploy executable file and bootstrap to AWS Lambda.
   

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7. let boto3 = Python.import("boto3")
   let dynamodb = boto3.resource("dynamodb")
   let table = dynamodb.Table("swift-sample")
   print("\(table.scan())")
   

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8. But, a program stopped
   

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9. Problems
   1. Can't load shared libraries.
   2. The environment variable PYTHON_LIBRARY isn’t set.
   3. Can't find boto3 module.
   

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10. Use aws-lambda-swift
    Use aws-lambda-swift (Changed to use Swift 5).
    Deploy to shared libraries as a layer.
    And link dynamically when handling request in bootstrap.
    EXECUTABLE=$LAMBDA_TASK_ROOT/"$(echo $_HANDLER | cut -d. -f1)"
    /opt/swift-shared-libs/ld-linux-x86-64.so.2 --library-path /opt/swift-shared-libs/lib $EXECUTABLE
    

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11. Set env var and deploy boto3
    1. Search python lib path and Set an environment variable.
    PYTHON_LIBRARY=/usr/lib64/libpython2.7.so.1.0
    2. Deploy boto3 module as a layer. And set /opt/python as
    PYTHONPATH.
    $ docker run --privileged -it -v `pwd`:`pwd` -w `pwd` --rm amazonlinux
    $ yum install python2-pip
    $ pip install -t ./python boto3
    $ zip -r boto3.zip python
    

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12. import AWSLambdaSwift
    struct Event: Codable {
    }
    struct Result: Codable {
    let result: String
    }
    func sample(event: Event, context: Context) -> Result {
    let boto3 = Python.import("boto3")
    let dynamodb = boto3.resource("dynamodb")
    let table = dynamodb.Table("swift-sample")
    return Result(result: "\(table.scan())")
    }
    let runtime = try Runtime()
    runtime.registerLambda("sample", handlerFunction: sample)
    try runtime.start()
    

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14. We can develop
    Serverless app with Swift!!
    

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15. Reference
    • Custom AWS Lambda Runtimes
    • AWS Lambda Layers
    • Boto 3 - The AWS SDK for Python
    • aws-lambda-swift
    

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16. Thanks!
    

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