# a2a-router (FastAPI + DigitalOcean Gradient)

Super-basic app that routes messages either to a local echo or to a DigitalOcean Gradient inference endpoint.

## Features
- FastAPI with `/route` and `/healthz`
- Simple router: keyword/length heuristic or explicit `route_hint`
- Config via env/ConfigMap/Secret
- Docker + Kubernetes manifests (Deployment, Service, Ingress)
- Script to create a tiny DO Kubernetes cluster via `doctl`

## Configure
Environment variables used by the app:
- `GRADIENT_ENDPOINT_URL`: Full URL to your Gradient inference endpoint
- `GRADIENT_API_KEY`: API key/token for Gradient
- `GRADIENT_AUTH_SCHEME`: `authorization_bearer` (default) or `x_api_key`
- `ROUTE_KEYWORDS`: comma-separated keywords to force Gradient routing

## Local Run
```bash
python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
uvicorn app.main:app --host 0.0.0.0 --port 8080
```

Test:
```bash
curl -s http://localhost:8080/healthz
curl -s -X POST http://localhost:8080/route -H 'Content-Type: application/json' \
  -d '{"message":"call the gradient model"}' | jq
```

## Build & Push Image
Replace `YOUR_REGISTRY/YOUR_IMAGE:tag` appropriately.
```bash
docker build -t YOUR_REGISTRY/YOUR_IMAGE:latest .
docker push YOUR_REGISTRY/YOUR_IMAGE:latest
```

## Create a Small DO K8s Cluster
Requires `doctl` and `kubectl`.
```bash
chmod +x scripts/doctl_create_cluster.sh
./scripts/doctl_create_cluster.sh a2a-cluster nyc1 s-1vcpu-2gb 1.29.1-do.0 1
```

Install nginx ingress controller if needed:
```bash
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.10.1/deploy/static/provider/cloud/deploy.yaml
```

## Deploy to Kubernetes
1) Create/update secrets and config:
```bash
kubectl apply -f k8s/config-secrets.yaml
```

2) Set the image and domain in manifests, then apply:
```bash
# edit k8s/deployment.yaml -> set image
# edit k8s/ingress.yaml -> set host domain
kubectl apply -f k8s/deployment.yaml
kubectl apply -f k8s/ingress.yaml
```

3) Get the ingress address and point your DNS (A/AAAA record) to it manually.
```bash
kubectl get ingress a2a-router -o wide
```

## API
- `POST /route`
  - body: `{ message: string, route_hint?: 'local'|'gradient', metadata?: object }`
  - response: `{ route: 'local'|'gradient', output: object }`
- `GET /healthz`

## Notes
- To force Gradient usage, pass `route_hint: "gradient"` or include a keyword in `ROUTE_KEYWORDS`.
- If Gradient call fails, endpoint returns 502 with message.