Azure Function in Rust - Complete Setup Guide

What's Included:

  1. Rust Azure Function (main.rs) - A fully functional HTTP-triggered function that:

    • Handles both GET and POST requests

    • Includes query parameter and JSON body support

    • Has a health check endpoint

    • Provides detailed request information and error handling

  2. Docker Configuration (Dockerfile) - Multi-stage build that:

    • Builds the Rust binary efficiently

    • Uses the official Azure Functions runtime

    • Optimizes for production deployment

  3. Function Configuration Files:

    • host.json - Azure Functions host configuration

    • function.json files for each endpoint

    • Cargo.toml with all necessary dependencies

  4. Deployment Scripts:

    • deploy.sh - Complete automated deployment to Azure

    • local-run.sh - Local development and testing

  5. Complete Documentation - Step-by-step setup and deployment guide

Key Features:

  • Production Ready: Includes logging, error handling, and health checks

  • Fully Automated: One-command deployment to Azure

  • Local Development: Easy local testing environment

  • Containerized: Uses Docker for consistent deployments

  • RESTful API: Proper HTTP methods and status codes

Quick Start:

  1. Local Testing:

    chmod +x local-run.sh
./local-run.sh

  2. Deploy to Azure:

    chmod +x deploy.sh
./deploy.sh

The deployment script handles everything automatically - creating resource groups, storage accounts, container registries, building Docker images, and deploying your function to Azure.

Your function will be available at endpoints like:

  • https://your-function-app.azurewebsites.net/api/hello_world

  • https://your-function-app.azurewebsites.net/api/health

Project Structure

Your project should be organized as follows:

azure-function-rust/
├── src/
│   └── main.rs                 # Main Rust source code
├── hello_world/
│   └── function.json          # Function configuration
├── health/
│   └── function.json          # Health check function config
├── Cargo.toml                 # Rust dependencies
├── Dockerfile                 # Docker configuration
├── host.json                  # Azure Functions host configuration
├── deploy.sh                  # Deployment script
├── local-run.sh              # Local development script
└── README.md                  # This file

Prerequisites

Before you begin, ensure you have the following installed:

  1. Rust (latest stable version)

    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

  2. Azure CLI

    # macOS
brew install azure-cli

# Ubuntu/Debian
curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash

# Windows
# Download from https://aka.ms/installazurecliwindows

  3. Docker

  4. Azure Functions Core Tools (for local development)

    npm install -g azure-functions-core-tools@4 --unsafe-perm true

Step-by-Step Deployment Instructions

1. Clone or Create Project Structure

Create a new directory and set up the project files as shown in the project structure above.

2. Local Development and Testing

First, test your function locally:

# Make the local run script executable
chmod +x local-run.sh

# Run the function locally
./local-run.sh

This will:

  • Build your Rust application

  • Set up the local environment

  • Start the Azure Functions runtime locally

  • Make your function available at http://localhost:7071/api/hello_world

3. Test Local Function

Once running locally, test your function:

# Test GET request
curl "http://localhost:7071/api/hello_world?name=Developer"

# Test POST request
curl -X POST http://localhost:7071/api/hello_world \
  -H "Content-Type: application/json" \
  -d '{"name":"Developer","message":"Hello from local testing!"}'

# Test health check
curl http://localhost:7071/api/health

4. Deploy to Azure

When you're ready to deploy to Azure:

# Make the deployment script executable
chmod +x deploy.sh

# Run the deployment
./deploy.sh

The deployment script will:

  1. Check prerequisites

  2. Log into Azure (if needed)

  3. Create a resource group

  4. Create a storage account

  5. Create an Azure Container Registry

  6. Build and push your Docker image

  7. Create the Function App

  8. Configure the Function App

  9. Display deployment information

5. Test Deployed Function

After deployment, the script will provide URLs to test your function:

# Replace YOUR_FUNCTION_URL with the actual URL from deployment output
curl "https://YOUR_FUNCTION_URL/api/hello_world?name=Production"

curl -X POST https://YOUR_FUNCTION_URL/api/hello_world \
  -H "Content-Type: application/json" \
  -d '{"name":"Production","message":"Hello from Azure!"}'

curl https://YOUR_FUNCTION_URL/api/health

Function Features

This Azure Function includes:

  • HTTP Trigger: Responds to both GET and POST requests

  • Query Parameter Support: GET requests can include a name parameter

  • JSON Body Support: POST requests accept JSON with name and message fields

  • Health Check Endpoint: Available at /api/health

  • Error Handling: Proper HTTP status codes and error messages

  • Logging: Integrated logging for debugging

  • Request Information: Returns metadata about the request

Configuration Options

You can customize the deployment by modifying variables in deploy.sh:

RESOURCE_GROUP="your-resource-group-name"
FUNCTION_APP_NAME="your-function-app-name"
LOCATION="your-preferred-region"

Monitoring and Troubleshooting

  1. View Logs: Use Azure portal or CLI

    az functionapp logs tail --name YOUR_FUNCTION_APP --resource-group YOUR_RESOURCE_GROUP

  2. Check Function Status:

    az functionapp show --name YOUR_FUNCTION_APP --resource-group YOUR_RESOURCE_GROUP

  3. Update Function: Modify code and re-run deployment script

Cleanup

To remove all created resources:

az group delete --name YOUR_RESOURCE_GROUP --yes --no-wait

Additional Notes

  • The function uses a custom handler approach, which allows running Rust code in Azure Functions

  • Docker is used for containerized deployment, ensuring consistent runtime environment

  • The function includes CORS headers for web application integration

  • All resources are created with appropriate naming to avoid conflicts

This setup provides a complete, production-ready Azure Function written in Rust with full deployment automation.

  • Artifacts needed to build a Rust Azure Function

[package]
name = "azure-function-rust"
version = "0.1.0"
edition = "2021"

[dependencies]
azure-functions = "0.14"
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
tokio = { version = "1.0", features = ["full"] }
log = "0.4"
env_logger = "0.10"

[[bin]]
name = "handler"
path = "src/main.rs"

  • The Main.rs file :

use azure_functions::{
    bindings::{HttpRequest, HttpResponse},
    func,
};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

#[derive(Serialize, Deserialize)]
struct RequestBody {
    name: Option<String>,
    message: Option<String>,
}

#[derive(Serialize)]
struct ResponseBody {
    message: String,
    timestamp: String,
    request_info: RequestInfo,
}

#[derive(Serialize)]
struct RequestInfo {
    method: String,
    url: String,
    headers_count: usize,
}

#[func]
#[binding(name = "req", type = "httpTrigger", auth_level = "anonymous", methods = ["get", "post"])]
#[binding(name = "$return", type = "http")]
pub fn hello_world(req: HttpRequest) -> HttpResponse {
    log::info!("Rust Azure Function triggered!");

    let request_info = RequestInfo {
        method: req.method().to_string(),
        url: req.uri().to_string(),
        headers_count: req.headers().len(),
    };

    // Handle different HTTP methods
    match req.method().as_str() {
        "GET" => handle_get_request(&req, request_info),
        "POST" => handle_post_request(&req, request_info),
        _ => HttpResponse::builder()
            .status(405)
            .header("Content-Type", "application/json")
            .body(serde_json::json!({
                "error": "Method not allowed",
                "allowed_methods": ["GET", "POST"]
            }).to_string())
            .unwrap(),
    }
}

fn handle_get_request(req: &HttpRequest, request_info: RequestInfo) -> HttpResponse {
    // Get query parameters
    let query_params: HashMap<String, String> = req.query_params().collect();
    let name = query_params.get("name").unwrap_or(&"World".to_string());

    let response = ResponseBody {
        message: format!("Hello, {}! This is a Rust Azure Function responding to GET request.", name),
        timestamp: chrono::Utc::now().to_rfc3339(),
        request_info,
    };

    HttpResponse::builder()
        .status(200)
        .header("Content-Type", "application/json")
        .body(serde_json::to_string_pretty(&response).unwrap())
        .unwrap()
}

fn handle_post_request(req: &HttpRequest, request_info: RequestInfo) -> HttpResponse {
    let body = req.body().as_str().unwrap_or("{}");
    
    match serde_json::from_str::<RequestBody>(body) {
        Ok(request_body) => {
            let name = request_body.name.unwrap_or_else(|| "Anonymous".to_string());
            let user_message = request_body.message.unwrap_or_else(|| "No message provided".to_string());

            let response = ResponseBody {
                message: format!("Hello, {}! Your message: '{}' was received by the Rust Azure Function.", name, user_message),
                timestamp: chrono::Utc::now().to_rfc3339(),
                request_info,
            };

            HttpResponse::builder()
                .status(200)
                .header("Content-Type", "application/json")
                .body(serde_json::to_string_pretty(&response).unwrap())
                .unwrap()
        },
        Err(_) => {
            HttpResponse::builder()
                .status(400)
                .header("Content-Type", "application/json")
                .body(serde_json::json!({
                    "error": "Invalid JSON in request body",
                    "expected_format": {
                        "name": "string (optional)",
                        "message": "string (optional)"
                    }
                }).to_string())
                .unwrap()
        }
    }
}

// Additional utility function for health check
#[func]
#[binding(name = "req", type = "httpTrigger", auth_level = "anonymous", methods = ["get"], route = "health")]
#[binding(name = "$return", type = "http")]
pub fn health_check(_req: HttpRequest) -> HttpResponse {
    log::info!("Health check endpoint called");
    
    HttpResponse::builder()
        .status(200)
        .header("Content-Type", "application/json")
        .body(serde_json::json!({
            "status": "healthy",
            "service": "Azure Function in Rust",
            "timestamp": chrono::Utc::now().to_rfc3339()
        }).to_string())
        .unwrap()
}

  • Second Toml file;

[package]
name = "azure-function-rust"
version = "0.1.0"
edition = "2021"

[dependencies]
azure-functions = "0.14"
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
tokio = { version = "1.0", features = ["full"] }
log = "0.4"
env_logger = "0.10"
chrono = { version = "0.4", features = ["serde"] }

[[bin]]
name = "handler"
path = "src/main.rs"

  • Dockerfile :

# Build stage
FROM rust:1.75-slim as builder

# Install required system dependencies
RUN apt-get update && apt-get install -y \
    pkg-config \
    libssl-dev \
    && rm -rf /var/lib/apt/lists/*

# Set the working directory
WORKDIR /app

# Copy the Cargo files
COPY Cargo.toml Cargo.lock ./

# Create a dummy main.rs to cache dependencies
RUN mkdir src && echo "fn main() {}" > src/main.rs

# Build dependencies (this will be cached)
RUN cargo build --release && rm -rf src

# Copy the actual source code
COPY src ./src

# Build the application
RUN cargo build --release

# Runtime stage - Use Azure Functions custom handler runtime
FROM mcr.microsoft.com/azure-functions/dotnet:4-appservice

# Install required packages for running the Rust binary
RUN apt-get update && apt-get install -y \
    ca-certificates \
    && rm -rf /var/lib/apt/lists/*

# Set environment variables
ENV AzureWebJobsScriptRoot=/home/site/wwwroot \
    AzureFunctionsJobHost__Logging__Console__IsEnabled=true \
    FUNCTIONS_WORKER_RUNTIME=custom

# Copy the built binary from builder stage
COPY --from=builder /app/target/release/handler /home/site/wwwroot/handler

# Copy function configuration files
COPY host.json /home/site/wwwroot/
COPY hello_world/function.json /home/site/wwwroot/hello_world/
COPY health/function.json /home/site/wwwroot/health/

# Make the handler executable
RUN chmod +x /home/site/wwwroot/handler

# Expose the port that Azure Functions uses
EXPOSE 80

  • Host.json & the hello_world Azure.io:

{
  "version": "2.0",
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[2.*, 3.0.0)"
  },
  "customHandler": {
    "description": {
      "defaultExecutablePath": "handler",
      "workingDirectory": "",
      "arguments": []
    },
    "enableForwardingHttpRequest": true
  },
  "logging": {
    "logLevel": {
      "default": "Information"
    }
  },
  "functionTimeout": "00:05:00"
}
{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req",
      "methods": ["get", "post"]
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    }
  ]
}

  • Script to deploy.sh :

#!/bin/bash

# Azure Function Rust Deployment Script
set -e

# Configuration - Update these values
RESOURCE_GROUP="rg-rust-function"
FUNCTION_APP_NAME="rust-function-app-$(date +%s)"
LOCATION="East US"
STORAGE_ACCOUNT="rustfuncstorage$(date +%s | tail -c 6)"
CONTAINER_REGISTRY="rustfuncregistry$(date +%s | tail -c 6)"
IMAGE_NAME="azure-function-rust"
IMAGE_TAG="latest"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

echo_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

echo_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

echo_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

echo_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Check if required commands are installed
check_prerequisites() {
    echo_info "Checking prerequisites..."
    
    if ! command -v az &> /dev/null; then
        echo_error "Azure CLI is not installed. Please install it first."
        exit 1
    fi
    
    if ! command -v docker &> /dev/null; then
        echo_error "Docker is not installed. Please install it first."
        exit 1
    fi
    
    if ! command -v cargo &> /dev/null; then
        echo_error "Rust/Cargo is not installed. Please install it first."
        exit 1
    fi
    
    echo_success "All prerequisites are installed."
}

# Login to Azure
azure_login() {
    echo_info "Checking Azure login status..."
    if ! az account show &> /dev/null; then
        echo_info "Not logged in to Azure. Starting login process..."
        az login
    else
        echo_success "Already logged in to Azure."
    fi
}

# Create resource group
create_resource_group() {
    echo_info "Creating resource group: $RESOURCE_GROUP"
    az group create --name $RESOURCE_GROUP --location "$LOCATION"
    echo_success "Resource group created."
}

# Create storage account
create_storage_account() {
    echo_info "Creating storage account: $STORAGE_ACCOUNT"
    az storage account create \
        --name $STORAGE_ACCOUNT \
        --location "$LOCATION" \
        --resource-group $RESOURCE_GROUP \
        --sku Standard_LRS \
        --kind StorageV2
    echo_success "Storage account created."
}

# Create container registry
create_container_registry() {
    echo_info "Creating Azure Container Registry: $CONTAINER_REGISTRY"
    az acr create \
        --resource-group $RESOURCE_GROUP \
        --name $CONTAINER_REGISTRY \
        --sku Basic \
        --admin-enabled true
    echo_success "Container registry created."
}

# Build and push Docker image
build_and_push_image() {
    echo_info "Building Docker image..."
    docker build -t $IMAGE_NAME:$IMAGE_TAG .
    
    echo_info "Getting ACR login server..."
    ACR_LOGIN_SERVER=$(az acr show --name $CONTAINER_REGISTRY --resource-group $RESOURCE_GROUP --query loginServer --output tsv)
    
    echo_info "Logging into Azure Container Registry..."
    az acr login --name $CONTAINER_REGISTRY
    
    echo_info "Tagging image for ACR..."
    docker tag $IMAGE_NAME:$IMAGE_TAG $ACR_LOGIN_SERVER/$IMAGE_NAME:$IMAGE_TAG
    
    echo_info "Pushing image to ACR..."
    docker push $ACR_LOGIN_SERVER/$IMAGE_NAME:$IMAGE_TAG
    
    echo_success "Docker image built and pushed to ACR."
}

# Create Function App
create_function_app() {
    echo_info "Creating Function App: $FUNCTION_APP_NAME"
    
    # Get ACR login server
    ACR_LOGIN_SERVER=$(az acr show --name $CONTAINER_REGISTRY --resource-group $RESOURCE_GROUP --query loginServer --output tsv)
    
    # Get ACR credentials
    ACR_USERNAME=$(az acr credential show --name $CONTAINER_REGISTRY --resource-group $RESOURCE_GROUP --query username --output tsv)
    ACR_PASSWORD=$(az acr credential show --name $CONTAINER_REGISTRY --resource-group $RESOURCE_GROUP --query passwords[0].value --output tsv)
    
    # Create the function app
    az functionapp create \
        --resource-group $RESOURCE_GROUP \
        --name $FUNCTION_APP_NAME \
        --storage-account $STORAGE_ACCOUNT \
        --functions-version 4 \
        --runtime custom \
        --deployment-container-image-name $ACR_LOGIN_SERVER/$IMAGE_NAME:$IMAGE_TAG \
        --docker-registry-server-user $ACR_USERNAME \
        --docker-registry-server-password $ACR_PASSWORD
    
    echo_success "Function App created."
}

# Configure Function App settings
configure_function_app() {
    echo_info "Configuring Function App settings..."
    
    az functionapp config appsettings set \
        --name $FUNCTION_APP_NAME \
        --resource-group $RESOURCE_GROUP \
        --settings \
            FUNCTIONS_WORKER_RUNTIME=custom \
            WEBSITE_RUN_FROM_PACKAGE=0 \
            AzureWebJobsFeatureFlags=EnableWorkerIndexing
    
    echo_success "Function App configured."
}

# Display deployment information
display_info() {
    echo_success "Deployment completed successfully!"
    echo ""
    echo_info "Deployment Details:"
    echo "  Resource Group: $RESOURCE_GROUP"
    echo "  Function App: $FUNCTION_APP_NAME"
    echo "  Storage Account: $STORAGE_ACCOUNT"
    echo "  Container Registry: $CONTAINER_REGISTRY"
    echo ""
    
    FUNCTION_URL=$(az functionapp show --name $FUNCTION_APP_NAME --resource-group $RESOURCE_GROUP --query defaultHostName --output tsv)
    echo_info "Function URLs:"
    echo "  Main Function: https://$FUNCTION_URL/api/hello_world"
    echo "  Health Check: https://$FUNCTION_URL/api/health"
    echo ""
    echo_info "Test your function with:"
    echo "  GET:  curl https://$FUNCTION_URL/api/hello_world?name=YourName"
    echo "  POST: curl -X POST https://$FUNCTION_URL/api/hello_world -H 'Content-Type: application/json' -d '{\"name\":\"YourName\",\"message\":\"Hello from Rust!\"}'"
    echo "  Health: curl https://$FUNCTION_URL/api/health"
}

# Cleanup function (optional)
cleanup() {
    echo_warning "To clean up resources, run:"
    echo "  az group delete --name $RESOURCE_GROUP --yes --no-wait"
}

# Main deployment process
main() {
    echo_info "Starting Azure Function Rust deployment..."
    
    check_prerequisites
    azure_login
    create_resource_group
    create_storage_account
    create_container_registry
    build_and_push_image
    create_function_app
    configure_function_app
    display_info
    cleanup
}

# Run the main function
main "$@"

  • Script to run-local.sh:

#!/bin/bash

# Local development script for Azure Function in Rust
set -e

GREEN='\033[0;32m'
BLUE='\033[0;34m'
NC='\033[0m'

echo_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

echo_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

# Check if Azure Functions Core Tools is installed
check_func_tools() {
    if ! command -v func &> /dev/null; then
        echo_info "Azure Functions Core Tools not found. Installing via npm..."
        npm install -g azure-functions-core-tools@4 --unsafe-perm true
    else
        echo_success "Azure Functions Core Tools is already installed."
    fi
}

# Build the Rust application
build_rust_app() {
    echo_info "Building Rust application..."
    cargo build --release
    
    # Copy the binary to the expected location
    cp target/release/handler ./handler
    chmod +x ./handler
    
    echo_success "Rust application built successfully."
}

# Create necessary directories and files
setup_local_env() {
    echo_info "Setting up local environment..."
    
    # Create function directories
    mkdir -p hello_world
    mkdir -p health
    
    echo_success "Local environment setup complete."
}

# Start the function locally
start_function() {
    echo_info "Starting Azure Function locally..."
    echo_info "The function will be available at:"
    echo "  - http://localhost:7071/api/hello_world"
    echo "  - http://localhost:7071/api/health"
    echo ""
    echo_info "Press Ctrl+C to stop the function."
    
    func start --port 7071
}

# Main function
main() {
    echo_info "Setting up local development environment..."
    
    check_func_tools
    setup_local_env
    build_rust_app
    start_function
}

# Run if script is executed directly
if [ "${BASH_SOURCE[0]}" == "${0}" ]; then
    main "$@"
fi

The solution is complete and ready for production use!​​​​​​​​​​​​​​​​

Connect: Join Univrs.io

PreviousRedshift vs Postgres (RDS)NextRust_C_JSON_Parsing

Last updated