API Gateway

The FnKit gateway provides centralized token authentication and routing for all your function containers. It’s an nginx-based reverse proxy with a built-in Bun orchestrator for multi-function pipelines.

Architecture

Request → Gateway (port 8080)
  ├── /health              → 200 OK (no auth)
  ├── /orchestrate/<name>  → Bun orchestrator (pipelines)
  └── /<container-name>/*  → proxy to function container

All function containers and the gateway sit on the same Docker network (fnkit-network). The gateway resolves container names via Docker DNS and proxies requests to port 8080 on each container.

Quick Start

# Create the Docker network
docker network create fnkit-network

# Generate gateway project files
fnkit gateway init

# Build the Docker image
fnkit gateway build

# Start with token authentication
fnkit gateway start --token your-secret-token

Calling Functions

# Call a function through the gateway
curl -H "Authorization: Bearer your-secret-token" http://localhost:8080/my-function

# Path forwarding — everything after the function name is forwarded
curl -H "Authorization: Bearer your-secret-token" http://localhost:8080/my-function/api/users?page=2

# Health check (no auth required)
curl http://localhost:8080/health

Authentication

The gateway supports two modes:

Token Mode (recommended)

Start with --token to require a Bearer token on all requests:

fnkit gateway start --token your-secret-token

Requests must include Authorization: Bearer your-secret-token. Invalid or missing tokens return 401 Unauthorized.

Open Mode

Start without --token for open access (useful for development):

fnkit gateway start

All requests are proxied without authentication.

How Routing Works

The gateway uses nginx with Docker DNS resolution:

Request arrives at http://gateway:8080/<container-name>/path
If auth is enabled, validates the Authorization: Bearer <token> header
Resolves <container-name> via Docker DNS on fnkit-network
Proxies to http://<container-name>:8080/path
Returns the function’s response

If the container doesn’t exist or isn’t running, the gateway returns:

{ "error": "Function not found or not running", "container": "my-function" }

Orchestrator

The gateway includes a built-in Bun-based orchestrator for multi-function pipelines, accessed via the /orchestrate/<name> route. See the full Orchestrator documentation for details on sequential and parallel pipelines, managing pipelines, and configuration.

Gateway Project Files

fnkit gateway init creates a fnkit-gateway/ directory with:

File	Purpose
`nginx.conf.template`	Nginx config with token auth and dynamic routing
`Dockerfile`	Multi-stage build (nginx + Bun orchestrator)
`start.sh`	Startup script — injects env vars into nginx config
`docker-compose.yml`	For local testing with `docker compose up`
`orchestrator/index.ts`	Bun-based orchestrator server
`orchestrator/package.json`	Orchestrator dependencies (ioredis)
`README.md`	Gateway-specific documentation

Using Docker Compose

You can also run the gateway with Docker Compose:

cd fnkit-gateway

# Set your token
export FNKIT_AUTH_TOKEN=your-secret-token

# Start
docker compose up -d

Environment Variables

Variable	Description	Default
`FNKIT_AUTH_TOKEN`	Bearer token for authentication. Empty = open mode	(empty)
`CACHE_URL`	Valkey/Redis URL for pipeline configs	`redis://fnkit-cache:6379`

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