Drone nightly build

.drone.yml

# Build
build:
  image: golang:1.5
  environment:
    - GO15VENDOREXPERIMENT=1
    - GOOS=linux
    - GOARCH=amd64
    - CGO_ENABLED=0
  commands:
    - go get
    - go build
    - go test

# Publish
publish:
  docker:
    # Your values go here

crontab.template

# The o-59/x syntax runs the script every x minutues offset by o.
#
# 5-59/15 would mean that the script runs at 5, 20, 35, and 50 after.
#
# All projects are assumed to be building master. If not make a new entry
# that uses --branch.

0-59/15 * * * * root drone-cron --repo foo/bar --server {{SERVER}} --token {{TOKEN}} >> /var/log/cron.log 2>&1

Dockerfile

FROM ubuntu

# Add the files
ADD crontab.template \
    drone-cron \
    run.sh \
    /bin/
    
# Give execution rights
RUN chmod +x /bin/run.sh
RUN chmod +x /bin/drone-cron

# Run the script
CMD /bin/run.sh

main.go

package main

import (
	"flag"
	"log"
	"strings"

	"github.com/drone/drone-go/drone"
)

var (
	repo   = flag.String("repo", "", "repository name (ie octocat/hello-world")
	branch = flag.String("branch", "master", "repository branch (ie master)")
	token  = flag.String("token", "", "drone token")
	server = flag.String("server", "", "drone server")
)

func main() {
	flag.Parse()

	var (
		owner = strings.Split(*repo, "/")[0]
		name  = strings.Split(*repo, "/")[1]
	)

	client := drone.NewClientToken(*server, *token)
	builds, err := client.BuildList(owner, name)
	if err != nil {
		log.Fatalf("Unable to get build list for %s. %s", name, err)
	}

	for _, build := range builds {
		if build.Status == drone.StatusPending || build.Status == drone.StatusRunning {
			log.Fatalf("Build is already in progress for %s.", name)
		}
		if build.Branch == *branch && build.Event == "push" {
			forked, err := client.BuildFork(owner, name, build.Number)
			if err != nil {
				log.Fatalf("Unable to fork build %s/%s#%d. %s.", owner, name, build.Number, err)
			}
			log.Printf("Created new build for %s/%s@%s", owner, name, forked.Commit)
			break
		}
	}
}

run.sh

#!/bin/bash
set -ex

CRON_FILE=/etc/cron.d/drone-cron
CRON_LOG=/var/log/cron.log

# Create the crontab entry
sed -e s/{{SERVER}}/${DRONE_SERVER//\//\\/}/ \
    -e s/{{TOKEN}}/${DRONE_TOKEN//\//\\/}/ \
    /bin/crontab.template > $CRON_FILE
    
# Make it executable
chmod 0644 $CRON_FILE

# Create the log file
touch $CRON_LOG

# Run the cron command
cron && tail -f $CRON_LOG