The id and topology are enough to get some basic info for rendering.
This isn't just a fall-through for exceptional cases.
ContainerwithImageNameRenderer produces parent references using the
image name without version as the ID, and containers-by-image topology
uses that for grouping. By contrast, the container-image topology in
the report is keyed on docker image IDs.
We eliminate the custom parent renderer, which was a very partial
implementation MakeBasicNodeSummary.
We also ensure that parents are always rendered in the same, sensible
order. Previously the order was an alphabetic sort of the parent
topology IDs. Now lower level topologies come before higher level
topologies.
Pre-allocating slices really pays dividends when we create loads of
them and they don't grow very large.
We take special care to return nil rather than 0-length slices. This
a) saves further on allocation, and b) is required for some crude
tests to pass that match on nil rather than length.
Also, a bunch of code in templates/tables used slices as Maybe's,
i.e. returning nil or a single-element slice, which is horrendously
inefficient. Eliminating these saves a lot of allocations.
Use a special kind of selector renderer to elide replica sets from pod nodes
and directly reference deployment parents instead.
Do the inverse (replace replica sets with pods) during the mapping from pod to deployment.
Note we can no longer use renderParents since we're using a non-standard Selector
We replace the existing data structure with a simpler one that
only specifies how to get the parent label, which is the only
part of the Parent struct that can't be generated from the node info alone.
Future work: Standardize this concept of a label and put it in the topology instead.
Though that already exists...so just use it?
This is important for two reasons:
* It prevents nasty false-equality bugs when two different services from different ECS clusters
are present in the same report
* It allows us to retrieve the cluster and service name - all the info we need to look up the service -
using only the node ID. This matters, for example, when trying to handle a control request.
Squash of:
- including children in topologies_test.go
- report.Node.Prune should prune children also
- rewrote ShortLivedInternetConnections test to express its intent
- adding tests for detail Summary rendering
Squash of:
- use detailed.Summaries to render topology nodes
- ban merging nodes of different topologies (they should be mapped)
- need to prune parents when mapping node types
- render container images by id if they have no name
- remove separate render ids and prune parents in NewDerived*
- don't render metrics/metadata for groups of nodes
- fixing up tests
- removing pending unit tests (for mapping.go, for now)
- updating experimental dir for RenderableNode removal
