Limit errorMessage length on metrics endpoint

[flaviostutz]

On some of our deployments we had a problem with large error messages being used to notify errors because the /metrics endpoint starts to generate too much data on its output, specially if there are lots of different messages being tracked.

My proposal is to limit by default the maximum message output length to 50 chars in order to minimize accidental performance bottlenecks.

For example, the client do

req.setAttribute("error-info", "Some error is going on here, so please be patient while we finish our coffee!")

In this case the related errorMessage will be "Some error is going on here, so please be patient|"
The ending "|" indicates that the message was truncated.

What do you think?

[CarlosPanarello]

Or use a list of strings separated by comma passed by environment. Other solution will be create an interface/Enum as parameter for message error besides string.

[flaviostutz]

I didn't get it. Could you please write an example?

[CarlosPanarello]

For example create a environment like this
list_of_errors= keyError1:Error in http request, keyError2:name incorrect , keyError3:invalid data

Then create a class that gets this list and put in some Map to be access with the key parameter.

Or modify they method to add errorMessage to accept only Enum types, this will force to use only strings that will be create at build time.

[flaviostutz]

Could you exercise with some examples of messages, config and result, pls?

[CarlosPanarello]

Something like this to create a map from a environment
Then we can use this map to get value from key.

 String envs = "keyError1:Error in http request,keyError2:name incorrect,keyError3:invalid data";
        Arrays.stream(envs.split(","))
            .forEach(env -> map.put(env.split(":")[0].trim(), env.split(":" )[1].trim()));

        map.get("keyError1");