By reducing the number of times we refer to every topology by name line by line,
we make it easier to add new topologies, reduce the risk of bugs where a topology is not listed,
and reduce the risk of the repeated lines getting out of sync with each other.
We introduce two new methods to assist this:
WalkPairedTopologies, a modified WalkTopologies that gives the called function
the same topology from two reports. This is used, for example, to implement Copy and Merge.
TopologyMap, which returns a map of all topologies by name. This is then used to implement all other methods.
This leaves only 4 instances of listing topologies:
In the consts at the top of the file, to give it a name
In the struct itself
In the constructor, where we need to set per-topology settings
In TopologyMap
* remove randomness as far as possible
* make listener to close connections
* report time in a csv-friendly format
* remove tools from README
* rename time-scope-probe -> time-scope-probe-proc
* add time-scope-probe-cgroup
Instead of value being "" or omitted meaning "use group.Default", we now allow the empty value
to go through. This was done to allow multi-value options to be able to encode 'no options selected'.
This is important as the alternative is very confusing, as 'nothing selected' would generally mean
'match everything', not 'select default' (which in the k8s namespace example, means the "default" namespace).
Since the UI is the only user of this API, and it already sends the default value always, this does not affect
any existing usage.
Since the UI still wants to show a 'match all' button to prevent confusion, but it's not a normal option
(if it were a normal option, it could be combined with others, which isn't meaningful), we add a new key
NoneLabel that indicates the name that should be displayed on this extra button.
Finally, we implement these changes for the k8s namespace button, ie.
- Get rid of All Namespaces option
- Add "All Namespaces" as the NoneLabel
- Default to "" when "default" namespace not present, which is equivalent to the old "all" option.
This is the first usage of the new 'union' selectType.
Note that we're still sending 'all' for now. There's currently no easy
way to specify this meaning, and arguably it should be done entirely clientside.
But for now it just means some UI weirdness where 'all' is one of the options and having it on
means anything else you select doesn't matter.
This field changes the option group behaviour depending on its value.
Currently only supports two values:
"one" (default): Old behaviour, one option can be selected
"union": Any number of options can be selected, and the filters are OR-ed togther
It is written in such a way as to easily enable a future "intersection" option,
as per union but AND-ing the filters. But this is not done here. YAGNI.
