forked from GithubBackups/healthchecks
75 lines
2.1 KiB
Markdown
75 lines
2.1 KiB
Markdown
# Shell Scripts
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You can easily add SITE_NAME monitoring to a shell script. All you
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have to do is make a HTTP request at the end of the script.
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[curl](https://curl.haxx.se/docs/manpage.html) and
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[wget](https://www.gnu.org/software/wget/manual/wget.html)
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are two common command line HTTP clients you can use.
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```bash
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# Sending a HTTP GET request with curl:
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curl --retry 3 PING_URL
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# Silent version (no stdout/stderr output unless curl hits an error):
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curl -fsS --retry 3 PING_URL
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# Sending a HTTP GET request with wget:
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wget PING_URL -O /dev/null
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```
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## Signalling Failure from Shell Scripts
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You can append `/fail` to any ping URL and use the resulting URL to actively
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signal a failure. The below example:
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* runs `/usr/bin/certbot renew`
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* if the certbot command is successful (exit code 0), send HTTP GET to `PING_URL`
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* otherwise, send HTTP GET to `PING_URL/fail`
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```bash
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#!/bin/sh
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# Payload here:
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/usr/bin/certbot renew
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# Ping SITE_NAME
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curl --retry 3 "PING_URL$([ $? -ne 0 ] && echo -n /fail)"
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```
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## Logging Command Output
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When pinging with HTTP POST, you can put extra diagnostic information in request
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body. If the request body looks like a valid UTF-8 string, SITE_NAME
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will accept and store first 10KB of the request body.
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In the below example, certbot's output is captured and submitted via HTTP POST:
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```bash
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#!/bin/sh
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m=$(/usr/bin/certbot renew 2>&1)
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curl -fsS --retry 3 -X POST --data-raw "$m" PING_URL
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```
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## Auto-provisioning New Checks
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This example uses SITE_NAME [Management API](../api/) to create a check "on the fly"
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(if it does not already exist) and to retrieve its ping URL.
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Using this technique, you can write services that automatically
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register with SITE_NAME the first time they run.
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```bash
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#!/bin/bash
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API_KEY=your-api-key-here
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# Check's parameters. This example uses system's hostname for check's name.
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PAYLOAD='{"name": "'`hostname`'", "timeout": 60, "grace": 60, "unique": ["name"]}'
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# Create the check if it does not exist.
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# Grab the ping_url from JSON response using the jq utility:
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URL=`curl -s SITE_ROOT/api/v1/checks/ -H "X-Api-Key: $API_KEY" -d "$PAYLOAD" | jq -r .ping_url`
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# Finally, send a ping:
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curl --retry 3 $URL
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``` |