During rendering, RenderableNodes are created by Map funcs, which take only
NodeMetadata. Previously, it was simply assumed that the relevant keys for a
given Map func would be present in the metadata. If that implicit invariant
failed, the returned RenderableNode would be invalid, with e.g. an ID of
"hostid::". That, in turn, would trigger undefined behavior later on in the
rendering workflow.
This bug was detected by creating a partial node metadata for a non-local
endpoint node. That node was detected during the first phase of rendering, and
given an invalid renderable node ID of "myhostname::", which prevented it from
attaching to TheInternet pseudonode. It eventually got removed from the set
of valid nodes, which meant nodes that were adjacent to it suddenly became
orphans, and got filtered out by the FilterUnconnected step of the rendering
pipeline.
With this change, every map func checks for the presence of mandatory fields,
i.e. the fields that compose the resulting renderable node's ID.
Also,
- Add unit tests for LeafMapFuncs
- Topology Validate checks NodeMetadatas must not have nil Metadata
Also:
- build a custom URL matcher to cope with container image names having a encoded forward slash in them.
- escape node ids in the UI when constructing URLs.
- add a test which fetches all the nodes of all topologies, and update report fixture to have slash in container image names.
This makes container image details show the containers (and processes) correctly.
Also:
- introduces a 'test' package, moved Diff function there.
- adds some tests for this new rendered view.
