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README.md

Macro.swift Examples - Express on AWS Lambda

This is the same demo app like express-simple, it shows Mustache templates, endpoints and some middleware.

Looks like this: MacroExpress Simple Screenshot

Build & Deployment

This assumes that aws configure has been run to configure the AWS access tokens and region.

Call swift lambda build to build the demo for AWS, or just swift lambda deploy to deploy it, it'll build on demand:

swift lambda deploy -p express-simple-lambda -f HelloWorld
Lambda: express-simple-lambda.zip
{
  "FunctionName": "HelloWorld",
  "FunctionArn": "arn:aws:lambda:eu-west-3:123456789:function:HelloWorld:24",
  "Runtime": "provided",
  "Role": "arn:aws:iam::123456789:role/service-role/HelloWorld-role-xyz12ab3",
  "Handler": "hello.handler",
  "CodeSize": 23662925,
  "Description": "",
  "Timeout": 3,
  "MemorySize": 128,
  "LastModified": "2020-08-08T14:07:18.024+0000",
  "CodeSha256": "fykvewkSBes/zz/A/5xYkJ5jwPXaQrp1eJ8XsSARIT4=",
  "Version": "24",
  "TracingConfig": {
    "Mode": "PassThrough"
  },
  "RevisionId": "597e9e19-644f-4da7-bc7b-26cc9725ee07",
  "State": "Active",
  "LastUpdateStatus": "Successful"
}

What are the arguments?

  • -p express-simple-lambda selects the package manager product to be deployed as a function. This is needed because we have multiple products in the Package.swift (if the name matches the package directory, it can't be omitted)
  • -f HelloWorld configures the Lambda endpoint (the "function") we want to deploy into. Can be any Lambda configured in the AWS dashboard (or by other means)

Invoke swift lambda deploy -h to see all options.

Differences

A few adjustments had to be made:

  • Lambda.run is used when the server is running in Lambda. The regular listen is used when the server is run locally. (There is a third option: LOCAL_LAMBDA_SERVER_ENABLED of the Swift AWS Runtime).
  • the session related things have been removed, lambdas are not long running and cannot use the RAM based session middleware (the session module could be used, but a persistent backend, e.g. using DynamoDB, would be required)

Swift Source

#!/usr/bin/swift sh

import MacroLambda // @Macro-swift          ~> 0.5.0
import cows        // @AlwaysRightInstitute ~> 1.0.0

let app = express()

app.use(logger("dev"))
app.use(bodyParser.urlencoded())
app.use(cookieParser())
app.use(serveStatic(__dirname() + "/public"))

// MARK: - Express Settings

app.set("view engine", "html") // really mustache, but we want to use .html
app.set("views", __dirname() + "/views")

let taglines = [
    "Less than Perfect.",
    "Das Haus das Verrückte macht.",
    "Rechargeables included",
    "Sensible Server Side Swift aS a Successful Software Service Solution"
]

// MARK: - Form Handling

app.get("/form") { _, res in
    res.render("form")
}
app.post("/form") { req, res in
    let user = req.body[string: "u"]
    console.log("USER IS: \(user)")
  
    let options : [ String : Any ] = [
        "user"      : user,
        "nouser"    : user.isEmpty,
        "viewCount" : req.session["viewCount"] ?? 0
    ]
    res.render("form", options)
}


// MARK: - JSON & Cookies

app.get("/json") { _, res in
    res.json([
        [ "firstname": "Donald",   "lastname": "Duck" ],
        [ "firstname": "Dagobert", "lastname": "Duck" ]
    ])
}

app.get("/cookies") { req, res in
    // returns all cookies as JSON
    res.json(req.cookies)
}


// MARK: - Cows

app.get("/cows") { _, res in
    res.send("<html><body><pre>\(cows.vaca())</pre></body></html>")
}

// MARK: - Main page

app.get("/") { req, res in
    let tagline = taglines.randomElement()!
  
    let values : [ String : Any ] = [
        "tagline"     : tagline,
        "cowOfTheDay" : cows.vaca()
    ]
    res.render("index", values)
}

// MARK: - Start Server

if process.isRunningInLambda {
  Lambda.run(app)
}
else {
  app.listen(1337) {
    console.log("Server listening on http://localhost:1337")
  }
}

Links

Who

Macro is brought to you by ZeeZide. We like feedback, GitHub stars, cool contract work, presumably any form of praise you can think of.

There is a #microexpress channel on the Noze.io Slack. Feel free to join!