Fixes
- https://github.com/linkerd/linkerd2/issues/2962
- https://github.com/linkerd/linkerd2/issues/2545
### Problem
Field omissions for workload objects are not respected while marshaling to JSON.
### Solution
After digging a bit into the code, I came to realize that while marshaling, workload objects have empty structs as values for various fields which would rather be omitted. As of now, the standard library`encoding/json` does not support zero values of structs with the `omitemty` tag. The relevant issue can be found [here](https://github.com/golang/go/issues/11939). To tackle this problem, the object declaration should have _pointer-to-struct_ as a field type instead of _struct_ itself. However, this approach would be out of scope as the workload object declaration is handled by the k8s library.
I was able to find a drop-in replacement for the `encoding/json` library which supports zero value of structs with the `omitempty` tag. It can be found [here](https://github.com/clarketm/json). I have made use of this library to implement a simple filter like functionality to remove empty tags once a YAML with empty tags is generated, hence leaving the previously existing methods unaffected
Signed-off-by: Mayank Shah <mayankshah1614@gmail.com>
When changing templates, it's can be pretty time-intensive to
repair all test fixtures.
This change instruments CLI tests with two flags, `-update` and
`-pretty-diff` that control how test fixtures are diffed. When the
`-update` flag is set, the tests fixtures are overwritten as tests
execute. The `-pretty-diff` flag causes the full text of the fixture
to be printed on mismatch.
Add `linkerd uninject` command
uninject.go iterates through the resources annotations, labels,
initContainers and Containers, removing what we know was injected by
linkerd.
The biggest part of this commit is the refactoring of inject.go, to make
it more generic and reusable by uninject.
The idea is that in a following PR this functionality will get reused by
`linkerd inject` to uninject as as preliminary step to injection, as a
solution to #1970.
This was tested successfully on emojivoto with:
```
1) inject:
kubectl get -n emojivoto deployment -o yaml | bin/linkerd inject - |
kubectl apply -f -
2) uninject:
kubectl get -n emojivoto deployment -o yaml | bin/linkerd uninject - |
kubectl apply -f -
```
Also created unit tests for uninject.go. The fixture files from the inject
tests could be reused. But as now the input files act as outputs, they
represent existing resources and required these changes (that didn't
affect inject):
- Rearranged fields in alphabetical order.
- Added fields that are only relevant for existing resources (e.g.
creationTimestamp and status.replicas in StatefulSets)
Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>
Mayank Shah
Oliver Gould
Alejandro Pedraza
Thomas Rampelberg