Stumped by regular expression

[Richard_Grigsb1]

Requirement: build a health Check to send an api url call to server and parse the return value for key indicators.

URL: rldimedas1.tcbna.net/rest/apigateway/health/all

Crafted Send String: GET /rest/apigateway/health/all HTTP/1.1\r\nHost: rldimedas1.tcbna.net\r\nConnection: Close\r\n\r\n

User name and password required: DEVF5Inside / <password>

Expected return to be parsed:

{

  "status": "green",

  "elasticsearch": {

    "cluster_name": "DEV_EventDataStore",

    "status": "green",

    "number_of_nodes": "2",

    "number_of_data_nodes": "2",

    "timed_out": "false",

    "active_shards": "388",

    "initializing_shards": "0",

    "unassigned_shards": "0",

    "task_max_waiting_in_queue_millis": "0",

    "port_9240": "ok",

    "response_time_ms": "16"

  },

  "is": {

    "status": "green",

    "diskspace": {

      "status": "up",

      "free": "99419619328",

      "inuse": "152539549696",

      "threshold": "25195916902",

      "total": "251959169024"

    },

    "memory": {

      "status": "up",

      "freemem": "2668806528",

      "maxmem": "3817865216",

      "threshold": "368102604",

      "totalmem": "3681026048"

    },

    "servicethread": {

      "status": "up",

      "avail": "286",

      "inuse": "14",

      "max": "300",

      "threshold": "30"

    },

    "response_time_ms": "103"

  },

  "terracotta": {

    "status": "green",

    "nodes": "2",

    "healthy_nodes": "2",

    "response_time_ms": "67"

  }

}

3 Key Indicators of healthy Services:

#1

"elasticsearch": {

    "cluster_name": "DEV_EventDataStore",

    "status": "green",

#2

"is": {

    "status": "green",

#3

"terracotta": {

    "status": "green",

I would think it was possible to craft the received string parse to check for all 2 key indicators so I do not have to create 3 separate health checks.

I have tried just checking for the first indication by following suggestion in DevCentral but is did not work:

\"elasticsearch\": \{\"cluster_name\": \"DEV_EventDataStore\",\"status\": \"green\",

This solution is complicated by all 3 indicators being the same syntax: "status": "green"

I think there might be an issue with my GET string as well because the Monitor log only shows "200 OK" as the response from the server.

When I change the receive string to only elasticsearch, it passes.

Any Help Here?

[Simon_Blakely]

I always start my regex development at

regex101.com

(\"elasticsearch\")(.*)(\n\B)(\s*.*\n\B)(\s*\"status\": \"green\")

matches the first stanza.

It gets harder from there ...

[Richard_Grigsb1]

Could the issue actually be in the formatting of my GET string?

Here is the URL the DEV OPS Team gave me:

HTTPS:// rldimedas1.tcbna.net/rest/apigateway/health/all

Here is how I formatted the Send String:

GET /rest/apigateway/health/all HTTP/1.1\r\nHost: rldimedas1.tcbna.net\r\nConnection: Close\r\n\r\n

This request requires a username and password so they have been entered

[JRahm]

Could you use an external monitor so you can parse the json return data more cleanly than with REGEX? in python, that would be pretty simple:

from sys import stdout
resp = '''your json response string'''
if resp['elasticsearch']['status'] == 'green' and resp['is']['status'] == 'green' and resp['terracotta']['status'] == 'green':
    stdout.write('UP')
else:
    stdout.write('DOWN')
    
UP

You can find a full python external monitor sample here in the codeshare for RADIUS that you could modify to meet your needs.

[Richard_Grigsb1]

Issue resolved.

I discovered that the "Type" and "parent monitor" were set to "HTTPS" but SSL Profile was left at "NONE". I selected a generic ssl profile and the health check started functioning.

Here is what I end up with for the unique/per server in the pool/heath check.

Send String: GET /rest/apigateway/health/all HTTP/1.1\r\nHost: rldimedas1.tcbna.net\r\nConnection: Close\r\n\r\n

Receive String: elasticsearch.*cluster_name.*DEV_EventDataStore.*status.*green.*number_of_nodes.*status.*green.*diskspace.*terracotta.*status.*green.*nodes

The additional items in the receive string parse are so the F5 does not match subsequent  "status": "green" occurrences in the reply.

Thank You for your responses.

I am moving forward with the "monitoring server platform" idea that will provide an UP/DOWN HTML page for the F5 to check.