This isn't quite as neat as we'd want to make it, because two of the
three call sites still require a closure, but it's still an
improvement.
Note that every instance of MapEndpoints only ever maps to one
topology, which, furthermore, is a core report topology. Hence we can
just parameterise MapEndpoints with that topology, and then the map
functions can return just the node ids.
This is achieved by issuing an http request for each container to kubernetes' API, which yields one Reader for the corresponding container.
`logReadCloser' then reads from the above readers in parallel as data is available, buffering when necessary, forwarding it to clients by implementing the io.ReadCloser interface.
Old probes do not report namespace topologies.
`report.upgradeNamespaces()` recontructs namespace topologies using the data available from other kubernetes resources.
Also, add a test.
...which is useful if we want to disable periodic fetching of all
objects.
Previously the interval was also used to set the initial backoff of
the reconnect logic. A zero value there would result in _no_
backoff. So instead we now just use the default, which is 10s which
also happens to be the default probe.kubernetes.interval, so there is
no change in behaviour for the stock settings.
It's always set to render.FilterUnconnectedPseudo, so we can simply
use that constant in the one function (RendererForTopology) that
looked at that value.
After dropping extra metadata in the rest of this PR, our usage of
joinResults.add* only ever ends creating minimal nodes, from just an
id and topology. Hence joinResults.add* can be invoked with simply an
id and topology instead of a generic node creation function.
Some process nodes may not have a HostNodeID metadata, e.g. when an
endpoint references a pid that we know nothing about. When mapping
processes to containers, we therefore shouldn't rely on
HostNodeID. Instead we can obtain the hostID from the process node ID.
This has been broken for a while, possibly forever.
instead of a Map, since it's not really a map as it just updates the
given node.
This is more efficient and also matches what we do in similar
situations elsewhere, e.g. in ContainerWithImageNameRenderer and
ProcessWithContainerNameRenderer.
...when creating Uncontained pseudo nodes. Summarisation of
Uncontained/Umanaged only looks at the ID, which includes the
HostNodeID.
We adjust the promotion of Uncontained to Unmanaged, to operate on the
ID instead of (re)extracting the hostID from the HostNodeID
metadata. With that, nothing looks at the HostNodeID metadata of
Uncontained/Unmanaged nodes.
