There were two problems:
- the renderer was looking for reverse names on the destination
- the probe was not annotating source nodes with reverse-resolved names
Fixes#1847
The host CPU metric was reported as a percentage of all available CPUs,
but the limit was set to n_cpus * 100%. So on a 4-core machine the
graphs and metrics-on-canvas would never show more than 1/4th usage. Now
the limit is set to 100%.
Fixes#1664.
The container CPU metric was reported in units of 100% = 1 CPU. So the
the ratio was correct, but since we don't show limits in most places it
is hard to interpret that figure. It also makes sorting by CPU usage
highly misleading. So now we normalise everything to 100%. That too can
be misleading, depending on what you are looking for, but it's generally
less surprising.
The new probe will convert all node's LatestControls to Controls, so
the old app can consume them. Also, the new app will convert all
node's Controls to LatestControl, so it can consume the reports from
old probes.
This allows plugins to add controls to nodes that already have some
controls set by other plugin. Previously only the last plugin that
sets the controls in the node would have its controls visible. That
was because of NodeControls' Merge function that actually weren't
merging data from two inputs, but rather returning data that was newer
and discarding the older one.
This commit makes the LatestMap type a sort of a base class, that
should not be used directly. This also adds a generator for LatestMap
"concrete" types with a specific data type in the LatestEntry.
Plugins are queried for reports two times in a second. That's often
enough to get the shortcut reports. The reports are sent together with
the response.
Thanks to that, plugins can react to requests from controls they
exposed.
To make it work, plugins registry modifies each plugin's report by
prepending the plugin ID to the control name the plugin has exposed
before sending it to the app. Then the registry installs the control
request handler for this faked control name, which forwards the
request to the correct plugin.
This adds a new API endpoint to plugins next to "/report" - a
"/control" entry. The body of the request is the JSON-encoded
xfer.Request instance.
It is not a singleton anymore. Instead it is an object with a registry
backend. The default registry backend is provided, which is equivalent
to what used to be before. Custom backend can be provided for testing
purposes.
The registry also supports batch operations to remove and add handlers
as an atomic step.
We will want to put plugin id in a control id, which is sent to an app
and then to GUI. When we get a control request from GUI, we will want
to extract the plugin ID from the control name. To do it unambiguously
we need some separator made of chars that are not allowed in a plugin
name. This is to avoid the situation when there are two plugins:
"Plugin" and "PluginFoo". "Plugin" exposes a control named
"FooControl" and "PluginFoo" exposes a control named "Control". Faking
the control names which will be sent to the app would result in two
"PluginFooControl".
One possible option for plugin ID and control name separator would be
"/", but that won't work, since the request sent from GUI to the app
to <probe>/<node>/<control> would actually be
<probe>/<node>/<plugin>/<control> and as such wouldn't match the URL
template in RegisterControlRoutes().
