Fetcher Job Scheduler

This project demonstrates a lightweight job runner where each job defines its own execution interval directly in its source file.

Structure

• main.go wires signal handling and starts the scheduler.
• internal/scheduler contains the runner implementation that executes jobs on their declared cadence.
• jobs hosts job definitions; each job registers itself during package initialization.

Running

go run .

You should see the example job print a timestamp about every five seconds.

The scheduler will also start the clan monitor job once all required environment variables are present.

Creating a Job

1. Add a new file under jobs, for example jobs/fetch_users.go.
2. Declare any interval value in that file (e.g., const fetchInterval = 10 * time.Second).
3. Implement the jobs.Job interface and call Register in an init function.

package jobs

import (
    "context"
    "time"
)

const fetchInterval = 10 * time.Second

func init() {
    Register(&FetchUsersJob{})
}

type FetchUsersJob struct{}

func (FetchUsersJob) Name() string { return "fetch_users" }
func (FetchUsersJob) Interval() time.Duration { return fetchInterval }

func (FetchUsersJob) Run(ctx context.Context) error {
    // Perform work here.
    return nil
}

The scheduler automatically discovers and runs the new job without additional wiring.

Clan Monitor Job

The clan_monitor job checks your Clash of Clans clan members and sends a Discord DM when someone has been offline for at least two days. The job runs every 30 minutes and requires the following environment variables:

• COC_API_TOKEN: Clash of Clans developer API token.
• COC_CLAN_TAG: Clan tag (include the leading #, e.g. #123ABC).
• DISCORD_BOT_TOKEN: Discord bot token with permission to create DMs.
• DISCORD_RECIPIENT_ID: Your Discord user ID to receive notifications.

Example invocation:

export COC_API_TOKEN="..."
export COC_CLAN_TAG="#123ABC"
export DISCORD_BOT_TOKEN="..."
export DISCORD_RECIPIENT_ID="1234567890"
go run .

If any value is missing, the job logs clan monitor job disabled: <reason> during startup and will not register.

Docker Image

Build the container image:

docker build -t fetcher .

Run with the required environment variables:

docker run --rm \
  -e COC_API_TOKEN="..." \
  -e COC_CLAN_TAG="#123ABC" \
  -e DISCORD_BOT_TOKEN="..." \
  -e DISCORD_RECIPIENT_ID="1234567890" \
  fetcher