runitor

runitor

Runitor runs the supplied command, captures its output, and based on its exit code reports successful or failed execution to https://healthchecks.io or your private instance.

Healthchecks.io is a web service for monitoring periodic tasks. It's like a dead man's switch for your cron jobs. You get alerted if they don't run on time or terminate with a failure.

Installation

Download Signed Release Binaries

Binaries of the latest release for popular platforms are at https://github.com/bdd/runitor/releases/latest

Verify Signatures

SHA256 checksum manifest of the releases are signed with one of the SSH keys published at https://bdd.fi/x/runitor.pub.

An example verification script shows how to use ssh-keygen and sha256sum to verify downloads.

Build Locally

If you have Go 1.18 or newer installed, you can use the command:

go install bdd.fi/x/runitor/cmd/runitor@latest

...and the binary will be at $GOPATH/bin/runitor or if GOPATH isn't set, under $HOME/go/bin/runitor.

Cross Compilation

If you need to build the binary on a platform different than the target, you can pass the target operating system and architecture with GOOS and GOARCH environment variables to the go install command.

GOOS=plan9 GOARCH=arm go install bdd.fi/x/runitor/cmd/runitor@latest

...and the binary will be under $GOPATH/bin/plan9_arm/runitor.

Why Do I Need This Instead of Calling curl from a Shell Script?

In addition to clean separation of concerns from the thing that needs to run and the act of calling an external monitor, runitor packs a few neat extra features that are bit more involved than single line additions to a script.

It can capture the stdout and stderr of the command to send it along with execution reports, a.k.a. "pings". When you respond to an alert you can quickly start investigating the issue with the relevant context already available.

It can be used as a long running process acting as a task scheduler, executing the command at specified intervals. This feature comes in handy when you don't readily have access to a job scheduler like crond or systemd.timer. Works well in one process per container environments.

Example Uses

Certificate Renewal

# (Using per check UUIDs.)
export CHECK_UUID=8116e449-d71c-4112-8f5d-a66f60902091
runitor -- dehydrated --cron --config example.com.conf

Repository Maintenance

# Run the maintenance script 10 times a day (24h/10 = 2h 24m)
# (Using per-project ping key, and check slugs.)
export HC_PING_KEY=edf72661-62ff-49e7-a921-33b41502d7e7
runitor -slug git-repo-maintenance \
	-every 2h24m -- \
	/script/git-maint

Backup

# Do not attach output to ping.
# Backup software may leak filenames and paths.

runitor -no-output-in-ping -- restic backup /home /etc

Triggering an Immediate Run in Periodic Mode

When invoked with -every <duration> flag, runitor will also act as a basic task scheduler.

Sometimes you may not want to restart the process or the container just to force an immediate run. Instead, you can send SIGALRM to runitor to get it run the command right away and reset the interval.

pkill -ALRM runitor

Usage

runitor [-uuid uuid] -- command

Flags

-api-retries uint
  Number of times an API request will be retried if it fails with a transient error (default 2)
-api-timeout duration
  Client timeout per request (default 5s)
-api-url string
  API URL. Takes precedence over HC_API_URL environment variable (default "https://hc-ping.com")
-every duration
  If non-zero, periodically run command at specified interval
-no-output-in-ping
  Don't send command's output in pings
-no-run-id
  Don't generate and send a run id per run in pings
-no-start-ping
  Don't send start ping
-on-exec-fail value
  Ping type to send when runitor cannot execute the command (exit-code|success|fail|log (default fail))
-on-nonzero-exit value
  Ping type to send when command exits with a nonzero code (exit-code|success|fail|log (default exit-code))
-on-success value
  Ping type to send when command exits successfully (exit-code|success|fail|log (default success))
-ping-body-limit uint
  If non-zero, truncate the ping body to its last N bytes, including a truncation notice. (default 10000)
-ping-key string
  Ping Key. Takes precedence over HC_PING_KEY environment variable
-quiet
  Don't capture command's stdout
-req-header value
  Additional request header as "key: value" string
-silent
  Don't capture command's stdout or stderr
-slug string
  Slug of check. Requires a ping key. Takes precedence over CHECK_SLUG environment variable
-uuid string
  UUID of check. Takes precedence over CHECK_UUID environment variable
-version
  Show version

More on What healthchecks.io Provides

• It listens for HTTP requests (pings) from services being monitored.

• It keeps silent as long as pings arrive on time. It raises an alert as soon as a ping does not arrive on time.

• Pings can signal start of execution so run durations can be tracked.

• Pings can explicitly signal failure of execution so an alert can be send.

• Pings can attach up to 100KB of logs. Runitor automatically handles truncation if needed.

• It can alert you via email, SMS, WhatsApp, Slack, and many more services.

• It has a free tier with up to 20 checks.

• Software behind the service is open source. You can run your own instance if you'd like to.