#!/usr/bin/env python3
"""
Generate a Nomad job JSON for a static site deployment.
Reads from environment variables, prints JSON to stdout.
Pipe to: nomad job run -json -
"""

import json
import os
import sys

domain = os.environ["DOMAIN"]
site_hash = os.environ["SITE_HASH"]
server_image = os.environ.get("SERVER_IMAGE", "registry.toph.so/static-server:latest")
datacenter = os.environ.get("DATACENTER", "contabo")
s3_bucket = os.environ["S3_BUCKET"]

job_id = "site-" + domain.replace(".", "-")

startup_cmd = (
    f"mkdir -p /var/www && "
    f"aws s3 cp s3://{s3_bucket}/sites/{domain}/{site_hash}.tar.gz - "
    f"| tar xz -C /var/www/ && "
    f"exec static-web-server --port 8080 --root /var/www"
)

nomad_template_data = (
    '{{ with nomadVar "static-sites/s3" }}'
    "AWS_ACCESS_KEY_ID={{ .access_key }}\n"
    "AWS_SECRET_ACCESS_KEY={{ .secret_key }}\n"
    "AWS_ENDPOINT_URL={{ .endpoint }}\n"
    "{{ end }}"
)

job = {
    "Job": {
        "ID": job_id,
        "Name": job_id,
        "Namespace": "static-sites",
        "Type": "service",
        "Datacenters": [datacenter],
        "Update": {
            "MinHealthyTime": 5000000000,   # 5s in nanoseconds
            "HealthyDeadline": 60000000000,  # 60s in nanoseconds
            "MaxParallel": 1,
        },
        "TaskGroups": [
            {
                "Name": "site",
                "Count": 1,
                "Networks": [
                    {
                        "DynamicPorts": [
                            {"Label": "http", "To": 8080}
                        ]
                    }
                ],
                "Services": [
                    {
                        "Name": job_id,
                        "Provider": "nomad",
                        "PortLabel": "http",
                        "Tags": [
                            "traefik.enable=true",
                            f"traefik.http.routers.{job_id}.rule=Host(`{domain}`)",
                            f"traefik.http.routers.{job_id}.entrypoints=websecure",
                            f"traefik.http.routers.{job_id}.tls.certresolver=letsencrypt",
                        ],
                        "Checks": [
                            {
                                "Type": "http",
                                "Path": "/",
                                "Interval": 30000000000,  # 30s
                                "Timeout": 5000000000,    # 5s
                            }
                        ],
                    }
                ],
                "Tasks": [
                    {
                        "Name": "server",
                        "Driver": "docker",
                        "Config": {
                            "image": server_image,
                            "command": "/bin/bash",
                            "args": ["-c", startup_cmd],
                            "ports": ["http"],
                        },
                        "Templates": [
                            {
                                "EmbeddedTmpl": nomad_template_data,
                                "DestPath": "secrets/s3.env",
                                "Envvars": True,
                            }
                        ],
                        "Resources": {
                            "CPU": 100,
                            "MemoryMB": 128,
                        },
                    }
                ],
            }
        ],
    }
}

json.dump(job, sys.stdout, indent=2)
print()