Shell Scripts

You can easily add X-EYE monitoring to a shell script. All you have to do is make a HTTP request at an appropriate place in the script. curl and wget are two common command line HTTP clients you can use.

# Sends a HTTP GET request with curl:
curl -m 10 --retry 5 https://eye.xeung.tech/ping/your-uuid-here

# Silent version (no stdout/stderr output unless curl hits an error):
curl -fsS -m 10 --retry 5 -o /dev/null https://eye.xeung.tech/ping/your-uuid-here

Here's what each curl parameter does:

-m <seconds>: Maximum time in seconds that you allow the whole operation to take.
--retry <num>: If a HTTP request fails, retry up to this many times. By default, curl uses an increasing delay between each retry (1s, 2s, 4s, 8s, ...). See also --retry-delay.
-f, --fail: Makes curl treat non-200 responses as errors.
-s, --silent: Silent or quiet mode. Hides the progress meter, but also hides error messages.
-S, --show-error: Re-enables error messages when -s is used.
-o /dev/null: Redirect curl's stdout to /dev/null (error messages still go to stderr).

Signalling Failure from Shell Scripts

You can append /fail to any ping URL and use the resulting URL to actively signal a failure. The following example:

runs /usr/bin/certbot renew
if the certbot command is successful (exit code 0), sends HTTP GET to https://eye.xeung.tech/ping/your-uuid-here
otherwise, sends HTTP GET to https://eye.xeung.tech/ping/your-uuid-here/fail

#!/bin/sh

# Payload here:
/usr/bin/certbot renew
# Ping X-EYE
curl -m 10 --retry 5 "https://eye.xeung.tech/ping/your-uuid-here$([ $? -ne 0 ] && echo -n /fail)"

Logging Command Output

When pinging with HTTP POST, you can put extra diagnostic information in request body. If the request body looks like a valid UTF-8 string, X-EYE will accept and store first 10KB of the request body.

In the below example, certbot's output is captured and submitted via HTTP POST:

#!/bin/sh

m=$(/usr/bin/certbot renew 2>&1)
curl -fsS -m 10 --retry 5 --data-raw "$m" https://eye.xeung.tech/ping/your-uuid-here

Auto-provisioning New Checks

This example uses X-EYE Management API to create a check "on the fly" (if it does not already exist) and to retrieve its ping URL. Using this technique, you can write services that automatically register with X-EYE the first time they run.

#!/bin/bash

API_KEY=your-api-key-here

# Check's parameters. This example uses system's hostname for check's name.
PAYLOAD='{"name": "'`hostname`'", "timeout": 60, "grace": 60, "unique": ["name"]}'

# Create the check if it does not exist.
# Grab the ping_url from JSON response using the jq utility:
URL=`curl -s https://eye.xeung.tech/api/v1/checks/  -H "X-Api-Key: $API_KEY" -d "$PAYLOAD"  | jq -r .ping_url`

# Finally, send a ping:
curl -m 10 --retry 5 $URL