The services

The services section

Services are the main functionality of Epazote, is where the URL’s and the rules based on the response are defined, since options vary from service to service, an example could help better to understand the setup:

    my service 1:
        url: http://myservice.domain.tld/_healthcheck_
        timeout: 5
        seconds: 60
        log: http://monitor.domain.tld
            status: 200
                content-type: application/json
            body: find this string on my site
                cmd: sv restart /services/my_service_1
                notify: [email protected]
                msg: |
                    line 1 bla bla
                    line 2
                cmd: reboot
                cmd: sv restart /services/cache
                msg: restarting cache
                notify: [email protected] [email protected]
                cmd: restart abc
                notify: [email protected]
                msg: |
                    The rabbit is angry
                    & hungry
                cmd: svc restart /services/db

    other service:
        url: https://self-signed.ssl.tld/ping
            Origin: http://localhost
            Accept-Encoding: gzip
        insecure: true
            hours: 48
        minutes: 3

    redirect service:
        url: http://test.domain.tld/
        follow: yes
        hour: 1
            unhealthy: 1
            status: 302
                cmd: service restart abc
                notify: yes
                emoji: 1F600-1F621

        test: pgrep -f salt
            cmd: service restart salt_master
            notify: [email protected]

services - name of service (string)

An unique string that identifies your service, in the above example, there are 3 services named: - my service 1 - other service - redirect service

services - url (string)

URL of the service to supervise

services - follow (boolean true/false)

By default if a 302 Status code is received, Epazote will not follow it, if you would like to follow all redirects, this setting must be set to true.

services - insecure (boolean true/false)

This option explicitly allows Epazote to perform “insecure” SSL connections. It will disable the certificate verification.

services - ssl (seconds, minutes, hours)

Alert before the certificate expires:

    hours: 24

services - stop (int)

Defines the number or times the cmd will be executed, by default the cmd is executed only once, with the intention to avoid indefinitely loops. If value is set to -1 the cmd never stops. defaults to 0, stop 2 will execute “0, 1, 2” (3 times) the cmd.

services - timeout in seconds (int)

Timeout specifies a time limit for the HTTP requests, A value of zero means no timeout, defaults to 5 seconds.

services - retry_limit (int)

Specifies the number of times to retry an request, defaults to 3.

services - retry_interval (int)

Specifies the time between attempts in milliseconds. The default value is 500 (0.5 seconds).

services - read_limit (int)

Read only N number of bytes instead of the full body. This helps to make a more “complete” request and avoid getting an HTTP status code 408 when testing aws ELB.

services - threshold (healthy/unhealthy)

Alert after the threshold has been reached, by default is set to 0 (disabled):

    healthy: 2
    unhealth: 2

If set to 0 it will be disabled.

services - seconds, minutes, hours

How often to check the service, the options are: (Only one should be used)

  • seconds N
  • minutes N
  • hours N

N should be an integer, defaults to 60 seconds.

services - log (URL)

An URL to post all events, default disabled.

services - expect

The expect block options are: - status (int) - header (key, value) - body (regular expression) - if_not (Action block)

services - expect - status

An Integer representing the expected HTTP Status Code

services - expect - header (start_with match)

A key-value map of expected headers, it can be only one or more.

The headers will be considered valid if they starts with the required value, for example if you want to check for Content-type: application/json; charset=utf-8 you can simple do something like:

    Content-Type: application/json

This helps to simplify the matching and useful in cases where the headers changes, for example: Content-Range: bytes 100-64656926/64656927 can be matched with:

    Content-Range: bytes

services - expect - body

A regular expression used to match a string on the body of the site, use full in cases you want to ensure that the content delivered is always the same or keeps a pattern.

services - expect (How it works)

The expect logic tries to implement a if-else logic status, header, body are the if and the if_not block becomes the else.


In must cases only one option is required, check on the above example for the service named “redirect service”.

In case that more than one option is used, this is the order in how they are evaluated, no meter how they where introduced on the configuration file:

1. body
2. status
3. header

The reason for this order is related to performance, at the end we want to monitor/supervise the services in an efficient way avoiding to waste extra resources, in must cases only the HTTP Headers are enough to take an action, therefore we don’t need to read the full body page, because of this if no body is defined, Epazote will only read the Headers saving with this time and process time.

services - expect - if_not

if_not is a block with an action of what to do it we don’t get what we where expecting (expect). See services - Actions

services - if_status & if_header

There maybe cases in where third-party dependencies are down and because of this your application could not be working properly, for this cases the if_status and if_header could be useful.

For example if the database is your application could start responding an status code 500 or either a custom header and based on does values take execute an action:

The format for if_status is a key-pair where key is an int representing an HTTP status code, and the value an Action option

The format for if_header is a key-pair where key is a string of something you could relate/match and has in other if_X conditions, value is an Action.

This are the only if's and the order of execution: 1. if_status 2. if_header 3. if_not

This means that if a service uses if_status and if_not, it will evaluate first the if_status and execute an Action if required, in case an if_status and if_header are set, same applies, first is evaluated if_status, then if_header and last if_not.

services - Actions

An Action has five options: - cmd - notify - msg - emoji - http

They can be used all together, only one or either none.

services - Actions - cmd (string)

cmd Contains the command to be executed.

services - Actions - notify (string)

notify Should contain yes, the email email address or addresses (space separated) of the recipients that will be notified when the action is executed.

If the string is yes the global recipients will be used.

services - Actions - msg (list)

- send this if exit 0 (all OK)
- send this if exit 1 (something is wrong)

Based on the exit status either msg[0] or msg[1] is used,

services - Actions - emoji (list)

emoji Unicode characters to be used in the subject, example:

- 1F600
- 1F621

If services are OK they will use the first 1F600 if not they will use 1F621, if set to 0 no emoji will be used. The idea behind using unicode/emoji is to cough attention faster and not just ignore the email thinking is spam.

service - Actions - http (list(key, value))

A custom URL to GET/POST depending on the exit status, example:

- url: ""
- url: ""
    Content-Type: application/x-www-form-urlencoded
    data: |
    method: POST

When a service fails or returns an exit 1 the second url with method POST and the custom data will be used, notice that all the ocurances on the data that are within an _(key)_ will be replaced with the corresponding value, in this case:


will be replaced with:

 room_id=10&from=Alerts&message=SERVICE NAME+exit+code+0

When recovery the first url will be used, in this case will be a GET instead of a post, so:


notice that the name, exit, because are been replaced with the values of name, exit, because of the service.

services - Test

Epazote It is mainly used for HTTP services, for supervising other applications that don’t listen or accept HTTP connections, like a database, cache engine, etc. There are tools like daemontools, immortal as already mentioned, even so, Epazote can eventually be used to execute an action based on the exit of a command for example:

    test: pgrep -f salt
        cmd: service restart salt_master
        notify: [email protected]

In this case: test: pgrep -f salt will execute the cmd on the if_not block in case the exit code is > 0, from the pgrep man page:

    The pgrep and pkill utilities return one of the following values upon exit:

        0       One or more processes were matched.
        1       No processes were matched.
        2       Invalid options were specified on the command line.
        3       An internal error occurred.

Extra setup

green dots give some comfort – Because of this when using the log option an extra service could be configure as a receiver for all the post that Epazote produce and based on the data obtained create a custom dashboard, something similar to: or