Script from my blog post "Using systemd as a better cron." https://medium.com/horrible-hacks/using-systemd-as-a-better-cron-a4023eea996d. ⚠️ It may not actually work. 🤷‍♂️

generate-systemd-schedule.js

const fs = require("fs");

const getTimerTemplate = (platform, importType, interval) => `
[Unit]
Description=Run ${platform}-${importType} every 15 minutes
Requires=${platform}-${importType}.service

[Timer]
Unit=${platform}-${importType}.service
OnUnitInactiveSec=${interval}
RandomizedDelaySec=${interval}
AccuracySec=1s

[Install]
WantedBy=timers.target
`;

const getServiceTemplate = (platform, importType, cmd) => `
[Unit]
Description=Runs ${platform} ${importType}
# This will auto-start the cron timer
Wants=${platform}-${importType}.timer

[Service]
ExecStart=${cmd}
WorkingDirectory=/app/shoes-scraper
Slice=shoes-scraper.slice

[Install]
WantedBy=multi-user.target
`;

const getSliceTemplate = () => `
[Unit]
Description=Limited resources Slice
DefaultDependencies=no
Before=slices.target

[Slice]
CPUQuota=80%
MemoryLimit=2.7G
`;

const getInstallTemplate = services => `
#!/usr/bin/env bash

set -e
set -x

systemctl daemon-reload && systemctl stop ${services
  .map(service => `${service}`)
  .join(" ")}

systemctl daemon-reload && systemctl enable ${services
  .map(service => `${service}.timer`)
  .join(" ")}


systemctl daemon-reload && systemctl start ${services
  .map(service => `${service}.timer`)
  .join(" ")}

sudo /etc/init.d/datadog-agent start
`;

const InstallPath = "/etc/systemd/system";

const services = [];

[
  {
    importType: "recent",
    interval: "15m",
    platform: "shopify",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --recent --platform shopify"
  },
  {
    importType: "full",
    interval: "12h",
    platform: "shopify",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --full --platform shopify"
  },
  {
    importType: "recent",
    interval: "30m",
    platform: "nike",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --recent --platform nike"
  },
  {
    importType: "full",
    interval: "18h",
    platform: "nike",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --full --platform nike"
  },
  {
    importType: "recent",
    interval: "1h",
    platform: "adc",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --recent --platform adc"
  },
  {
    importType: "full",
    interval: "18h",
    platform: "adc",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --full --platform adc"
  },
  {
    importType: "recent",
    interval: "1h",
    platform: "sns",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --recent --platform sns"
  },
  {
    importType: "full",
    interval: "24h",
    platform: "sns",
    cmd:
      "/usr/local/bin/node /app/shoes-scraper/src/scraper --full --platform sns"
  },
].forEach(({ importType, interval, platform, cmd }) => {
  const serviceName = `${platform}-${importType}`;

  fs.writeFileSync(
    `${InstallPath}/${platform}-${importType}.timer`,
    getTimerTemplate(platform, importType, interval)
  );

  fs.writeFileSync(
    `${InstallPath}/${platform}-${importType}.service`,
    getServiceTemplate(platform, importType, cmd)
  );

  fs.writeFileSync(
    `${InstallPath}/shoes-scraper.slice`,
    getSliceTemplate(platform, importType)
  );

  services.push(serviceName);
});

fs.writeFileSync(`/tmp/install-timers.sh`, getInstallTemplate(services));