Throws exceptions when missing field keys

[hiql]

Hi, Bro:

I use your lib to parse tomcat access logs, and I got exceptions because of missing the field key "BYTES:request.body.bytes", I understand that it is an intentional behavior, but sometimes some fields are not important, we hope to continue the process, and to give a null value to the missing fields.

how should I do?

In TomcatAccessLog.java

    @Field("BYTES:request.body.bytes")
    public void setBytesReceived(final String value) {
        results.put("BYTES:request.body.bytes", value);
    }

format: %h %l %u %t "%r" %s %b

log: 223.104.131.76 - - [09/Feb/2023:00:00:17 +0800] "POST /cashier/submit HTTP/1.1" 200 1554

exception: nl.basjes.parse.core.exceptions.MissingDissectorsException: BYTES:request.body.bytes

[nielsbasjes]

You are asking for a field that does not exist in the specified logformat.

You have the response bytes (%b) yet you ask for the request bytes ... which is simply not part of the provided logformat.

As a consequence you get this intentional error because this cannot yield a value in any situation.

I see the Tomcat documentation shows:

%b - Bytes sent, excluding HTTP headers, or '-' if zero

I consider this confusing... sent to the server or sent to the client?.

The Apache HTTPD documentation says it clearer:

%b - Size of response in bytes, excluding HTTP headers. In CLF format, i.e. a '-' rather than a 0 when no bytes are sent.

When using my parser the easiest way to get information about what you CAN get out of a logformat is doing this:

String logFormat = "%h %l %u %t \"%r\" %s %b";
Parser<Object> parser = new HttpdLoglineParser<>(Object.class, logFormat);
parser.getPossiblePaths().forEach(System.out::println);

which will give you (among many other things)

BYTES:response.body.bytes

[hiql]

I see.

I found this method recordHttpdLoglineParser.ignoreMissingDissectors();

Thanks for your help:)

[nielsbasjes]

Just to be clear: The system says you will never receive a value on the requested value because there is no possible situation where it can calculate this value. And you solution is to ignore this error.

Curious: What is the benefit of doing it this way in your project?