JSONPath preprocessing null values
Zabbix 6.2 and 7.4
Lets consider the JSON set below.
Using Zabbix preprocessing, I'm trying to count the number of objects with the "STATUS" parameter equal to "S" and a non-null "ERR_PARAMS" value.
To do so, I added the following JSONPath.
With Zabbix 6.2, I tested the preprocessing step and Zabbix returned a value of 0. (CORRECT)
With Zabbix 7.4, I tested the preprocessing step and Zabbix returned a value of 2. (INCORRECT)
The correct value is 0 because both JSON objects have the "ERR_PARAMS" parameter set to null.
Setting @.ERR_PARAMS != 'null' should not be correct because the single quotes treat the value "null" as a string, which is not in the JSON object.
When I remove the quotes from the expression, Zabbix returns me an error.
I'm confused...
Why would Zabbix return different values for the exact same JSONPath and exact same JSON data?
It seems that Zabbix does not support the actual JSON nulls at all.
Lets consider the JSON set below.
Code:
[
{
"IDENTIFIER": "123456789",
"SEQUENCE_NO": "6",
"EXTERNAL_SYSTEM": "SYSTEM",
"PROCESS_DATE": "2026-04-14 00:00:00",
"BRANCH_CODE": "LLL",
"MODULE": "AC",
"OPERATION": "CREATE",
"FUNCTION_ID": "NOACBLOL",
"ONLINE_FLAG": "Y",
"STATUS": "S",
"RETRY_COUNT": null,
"ERR_CODE": null,
"ERR_PARAMS": null,
"ERR_MSG": null,
"RECORD_STAT": "O",
"AUTH_STAT": "A",
"MOD_NO": "1",
"MAKER_ID": "SYSTEM",
"MAKER_DT_STAMP": "2026-04-14 00:07:33",
"CHECKER_ID": "SYSTEM",
"CHECKER_DT_STAMP": "2026-04-14 00:07:33",
"ONCE_AUTH": "Y"
},
{
"IDENTIFIER": "123456780",
"SEQUENCE_NO": "6",
"EXTERNAL_SYSTEM": "SYSTEM",
"PROCESS_DATE": "2026-04-14 00:00:00",
"BRANCH_CODE": "LLL",
"MODULE": "AC",
"OPERATION": "CREATE",
"FUNCTION_ID": "NOACBLOL",
"ONLINE_FLAG": "Y",
"STATUS": "S",
"RETRY_COUNT": null,
"ERR_CODE": null,
"ERR_PARAMS": null,
"ERR_MSG": null,
"RECORD_STAT": "O",
"AUTH_STAT": "A",
"MOD_NO": "1",
"MAKER_ID": "SYSTEM",
"MAKER_DT_STAMP": "2026-04-14 02:02:33",
"CHECKER_ID": "SYSTEM",
"CHECKER_DT_STAMP": "2026-04-14 02:02:33",
"ONCE_AUTH": "Y"
}
]
To do so, I added the following JSONPath.
Code:
$.[?(@.STATUS == 'S' && @.ERR_PARAMS != 'null')].length()
With Zabbix 7.4, I tested the preprocessing step and Zabbix returned a value of 2. (INCORRECT)
The correct value is 0 because both JSON objects have the "ERR_PARAMS" parameter set to null.
Setting @.ERR_PARAMS != 'null' should not be correct because the single quotes treat the value "null" as a string, which is not in the JSON object.
When I remove the quotes from the expression, Zabbix returns me an error.
Code:
cannot extract value from json by path "$.[?(@.STATUS == 'S' && @.ERR_PARAMS != null)].length()": unsupported construct in jsonpath starting with: "null)].length()"
Why would Zabbix return different values for the exact same JSONPath and exact same JSON data?
It seems that Zabbix does not support the actual JSON nulls at all.