BoxLang on Google Cloud Functions

Overview

BoxLang runs on Google Cloud Functions Gen 2 via the Java 21 runtime. The FunctionRunner bridge handles HTTP request mapping, handler routing, class caching, and response serialization — so you focus on writing BoxLang handler files.

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Architecture

HTTP Request
    → GCF Gen 2 (java21 runtime)
    → FunctionRunner (HttpFunction)
    → RequestMapper (HttpRequest → BoxLang event struct)
    → Route resolution (first URI segment → PascalCase → .bx file)
    → Handler compilation + class cache (warm invocations)
    → Method dispatch (run() or x-bx-function header)
    → BoxLang handler execution
    → ResponseMapper (response struct → HttpResponse)

Runtime entry point:

ortus.boxlang.runtime.gcp.FunctionRunner

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Starter Project

git clone https://github.com/ortus-boxlang/boxlang-starter-google-functions.git
cd boxlang-starter-google-functions

# Verify environment
./gradlew clean test

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Handler File Convention

Handlers live in src/main/bx/. The URI path maps to a PascalCase .bx file:

Request URI	Resolved handler
GET /	src/main/bx/Index.bx
GET /orders	src/main/bx/Orders.bx
POST /users	src/main/bx/Users.bx

Each handler file is a BoxLang class with a run() method:

// src/main/bx/Orders.bx
class {

    /**
     * Main GCF handler.
     *
     * @param event    HTTP event struct: { method, path, headers, body, queryString }
     * @param context  GCF context info
     * @param response Response struct to populate: { statusCode, body, headers }
     */
    function run( event, context, response ){
        response.statusCode = 200
        response.headers    = { "Content-Type": "application/json" }
        response.body       = serializeJSON({
            orders:  orderService.list(),
            total:   orderService.count()
        })
    }

}

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Calling Specific Methods (Header Routing)

Use the x-bx-function header to call a specific method on a handler class:

# Calls Orders.bx run() (default)
curl http://localhost:9099/orders

# Calls Orders.bx createOrder()
curl -H "x-bx-function: createOrder" -X POST http://localhost:9099/orders \
    -H "Content-Type: application/json" \
    -d '{"productId": 1, "qty": 2}'

In the handler:

class {
    function run( event, context, response ){
        // Default — list orders
    }

    function createOrder( event, context, response ){
        var data = deserializeJSON( event.body )
        var order = orderService.create( data )
        response.statusCode = 201
        response.body = serializeJSON( order )
    }
}

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Event Struct

The incoming HTTP request is mapped to an event struct:

// event properties
event.method       // "GET", "POST", "PUT", etc.
event.path         // "/orders/42"
event.headers      // Struct of HTTP headers
event.queryString  // Struct of parsed query parameters
event.body         // Raw request body string
event.json         // Parsed JSON body (if Content-Type: application/json)

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Environment Variables

Variable	Description
BOXLANG_GCP_ROOT	Root directory for handler .bx files. Default: src/main/bx
BOXLANG_GCP_DEBUGMODE	Disable class caching for hot reload during development
BOXLANG_GCP_CONFIG	Path to a custom boxlang.json configuration

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Local Development

# Start local GCF server (port 9099)
./gradlew runFunction

# Custom port
./gradlew runFunction -PtestPort=8080

# Enable debug mode (disables class cache for hot reload)
./gradlew runFunction -PdebugMode=true

# Custom function root
./gradlew runFunction -PfunctionRoot=/absolute/path/to/bx

Expected startup banner:

================================================================
 BoxLang GCF Function Invoker
 Listening on  : http://localhost:9099
 Function root : .../src/main/bx
 Debug mode    : false
 Press Ctrl+C to stop.
================================================================

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Testing Locally

# Simple GET
curl http://localhost:9099/

# POST with JSON payload
curl -X POST http://localhost:9099/orders \
    -H "Content-Type: application/json" \
    -d '{"productId": 1, "qty": 2}'

# Header-routed method
curl -H "x-bx-function: anotherMethod" http://localhost:9099/

# From a sample event file
curl -X POST http://localhost:9099/ \
    -H "Content-Type: application/json" \
    -d @workbench/sampleRequests/event-local.json

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Cold Start, Warm Start, Debug Mode

Mode	Behavior
Cold start	Runtime initializes; first request is slower
Warm invocation	Compiled handler class reused — fast
Debug mode ON	Class cache disabled; edits picked up immediately
Debug mode OFF (production)	Maximum performance via class caching

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Deploying to GCP

# Authenticate
gcloud auth login
gcloud config set project YOUR_PROJECT_ID

# Build the deployment ZIP
./gradlew buildZip

# Deploy via gcloud
gcloud functions deploy myBoxLangFunction \
    --gen2 \
    --runtime java21 \
    --region us-central1 \
    --entry-point ortus.boxlang.runtime.gcp.FunctionRunner \
    --source build/distributions/function.zip \
    --trigger-http \
    --allow-unauthenticated \
    --memory 512MB \
    --min-instances 0 \
    --max-instances 10

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Portability with AWS Lambda

Handler patterns are intentionally compatible between BoxLang GCF and AWS Lambda:

Feature	GCF	AWS Lambda
Handler class	FunctionRunner	LambdaRunner
Handler method	run()	run()
Method routing header	x-bx-function	x-bx-function
Event struct	Same structure	Same structure
Debug mode env var	BOXLANG_GCP_DEBUGMODE	BOXLANG_LAMBDA_DEBUGMODE

Many handlers can be shared between GCF and Lambda with minimal changes.

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Production Checklist

•  BOXLANG_GCP_DEBUGMODE=false in production
•  Handler files under src/main/bx/ named in PascalCase matching URI segments
•  Secrets injected as environment variables (not in code)
•  Memory: 512MB minimum; 1GB+ for database-heavy functions
•  Min-instances configured for latency-sensitive paths
•  Integration tests passing: ./gradlew clean test
•  Deployment ZIP built fresh before each deploy: ./gradlew buildZip