add a diff field for monitoring usages

[zffocussss]

it is designed to monitor if the cvd is uptodate.In my cases promethues + Blackbox-exporter.
in other words,if the value of diff is not 0,it means the cvd is required to check in time in case of expiration.

[zffocussss]

@benzino77
Please have a check,it is useful in a k8s monitor stack.

[benzino77]

I have no experience using balckbox-exporter but does using fail_if_body_json_matches_cel or fail_if_body_json_not_matches_cel not solve the problem (compare two values from returned json)?
There is an example in the documentation of blackbox-exporter https://github.com/prometheus/blackbox_exporter/blob/c9a32f5aafdb00e9f0059964880fb021fcb4cdf8/example.yml#L67

More information about CEL-SPEC is available here: https://github.com/google/cel-spec

[zffocussss]

I have no experience using balckbox-exporter but does using fail_if_body_json_matches_cel or fail_if_body_json_not_matches_cel not solve the problem (compare two values from returned json)? There is an example in the documentation of blackbox-exporter https://github.com/prometheus/blackbox_exporter/blob/c9a32f5aafdb00e9f0059964880fb021fcb4cdf8/example.yml#L67

More information about CEL-SPEC is available here: https://github.com/google/cel-spec

@benzino77 In my opinion,add a diff field in the response body for some data collectors is much more valuable,as it can reduce client work.

[benzino77]

I'm not super convinced to that idea. The localVersion and/or remoteVersion can be also something like: 1744738140a or 1744738140d then calculating a diff based on Number will end up with NaN (I think). Implementing that logic on Blackbox-Reporter side and having there just a boolean value: True (for same versions) and False (for different versions) may be a better approach.

[zffocussss]

I'm not super convinced to that idea. The localVersion and/or remoteVersion can be also something like: 1744738140a or 1744738140d then calculating a diff based on Number will end up with NaN (I think). Implementing that logic on Blackbox-Reporter side and having there just a boolean value: True (for same versions) and False (for different versions) may be a better approach.

So far,the database version is number.It is safe to use Number type to calculate the diff between local and remote.

[benzino77]

Still it can give "NaN" in case of situation when letters are added to the version:

> const a = "1234567"
undefined
> const b = "1234567a"
undefined
> const c = Number(a) - Number (b)
undefined
> c
NaN

I do believe that having that logic on "consumer" side is better approach.

[zffocussss]

Still it can give "NaN" in case of situation when letters are added to the version:

> const a = "1234567"
undefined
> const b = "1234567a"
undefined
> const c = Number(a) - Number (b)
undefined
> c
NaN

I do believe that having that logic on "consumer" side is better approach.

if you insist on the type of version,how about the below response.

{
    "data": {
        "diff": true,
        "local_clamav_db_signature": "27615",
        "remote_clamav_db_signature": "27615"
    },
    "success": true
}

in this case,if diff is true,it means the version need to be checked.
diff: remoteVersion === localVersion,