treewide: Ensure that binaries are built with at least Go 1.17

[twpayne]

Cilium relies on a number of Go features that are not covered by Go's
backward compatibility guarantee, for example:

• //go:embed (available since Go 1.16)
• //go:build (available since Go 1.17)

There may be other cases where, for example, we rely on bug fixes in the
standard library.

Building Cilium with an earlier version of Go may complete without
error, but there is no guarantee that the binary will behave correctly.

This PR adds //go:build tags to the main source file of each of the
principle binaries that will cause compilation to fail early and loudly
so the use of old toolchains can be detected quickly.

Signed-off-by: Tom Payne tom@isovalent.com

[twpayne]

The bug that triggered this PR was I ran make on a clean checkout of master:

$ git status
On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean

$ make
contrib/scripts/check-logging-subsys-field.sh
contrib/scripts/check-fmt.sh
Unformatted Go source code:
./Documentation/_api/v1/models/zz_generated.deepequal.go
diff -u ./Documentation/_api/v1/models/zz_generated.deepequal.go.orig ./Documentation/_api/v1/models/zz_generated.deepequal.go
--- ./Documentation/_api/v1/models/zz_generated.deepequal.go.orig       2021-09-06 15:10:13.546643942 +0200
+++ ./Documentation/_api/v1/models/zz_generated.deepequal.go    2021-09-06 15:10:13.546643942 +0200
@@ -1,3 +1,4 @@
+//go:build !ignore_autogenerated
 // +build !ignore_autogenerated
 
 // Copyright 2017-2021 Authors of Cilium
./Documentation/_api/v1/models/zz_generated.deepcopy.go
diff -u ./Documentation/_api/v1/models/zz_generated.deepcopy.go.orig ./Documentation/_api/v1/models/zz_generated.deepcopy.go
--- ./Documentation/_api/v1/models/zz_generated.deepcopy.go.orig        2021-09-06 15:10:13.554643998 +0200
+++ ./Documentation/_api/v1/models/zz_generated.deepcopy.go     2021-09-06 15:10:13.554643998 +0200
@@ -1,3 +1,4 @@
+//go:build !ignore_autogenerated
 // +build !ignore_autogenerated
 
 // Copyright 2017-2021 Authors of Cilium
./Documentation/_api/api/v1/models/zz_generated.deepequal.go
diff -u ./Documentation/_api/api/v1/models/zz_generated.deepequal.go.orig ./Documentation/_api/api/v1/models/zz_generated.deepequal.go
--- ./Documentation/_api/api/v1/models/zz_generated.deepequal.go.orig   2021-09-06 15:10:13.742645311 +0200
+++ ./Documentation/_api/api/v1/models/zz_generated.deepequal.go        2021-09-06 15:10:13.742645311 +0200
@@ -1,3 +1,4 @@
+//go:build !ignore_autogenerated
 // +build !ignore_autogenerated
 
 // Copyright 2017-2021 Authors of Cilium
./Documentation/_api/api/v1/models/zz_generated.deepcopy.go
diff -u ./Documentation/_api/api/v1/models/zz_generated.deepcopy.go.orig ./Documentation/_api/api/v1/models/zz_generated.deepcopy.go
--- ./Documentation/_api/api/v1/models/zz_generated.deepcopy.go.orig    2021-09-06 15:10:13.750645368 +0200
+++ ./Documentation/_api/api/v1/models/zz_generated.deepcopy.go 2021-09-06 15:10:13.750645368 +0200
@@ -1,3 +1,4 @@
+//go:build !ignore_autogenerated
 // +build !ignore_autogenerated
 
 // Copyright 2017-2021 Authors of Cilium
make: *** [Makefile:507: precheck] Error 1

Refs #17190 and specifically this comment:

Third commit adds //go:build lines in addition to existing //+build lines, as automatically done by gofmt in Go 1.17. Note that also some files generated by deepcopy-gen were changed. These changes will be lost on the next update until we update to a version of deepcopy-gen which includes kubernetes-sigs/controller-tools#595.

[twpayne]

Note that these early checks should also help shake out cases where out test infrastructure is using an older version of Go.

[tklauser]

Would be nice to update the make update-go-version target as well to update these //go:build lines based on the Go version specified in GO_VERSION.

[tklauser]

Refs #17190 and specifically this comment:

Third commit adds //go:build lines in addition to existing //+build lines, as automatically done by gofmt in Go 1.17. Note that also some files generated by deepcopy-gen were changed. These changes will be lost on the next update until we update to a version of deepcopy-gen which includes kubernetes-sigs/controller-tools#595.

FWIW, christarazi/controller-tools#1 should take care of updating our forked version of controller-tools to generate //go:build lines.

[twpayne]

Would be nice to update the make update-go-version target as well to update these //go:build lines based on the Go version specified in GO_VERSION.

Great idea, done.

[ldelossa]

Looks pretty good, one comment on making the discovery of main.go files more dynamic. Not sure if it over-searches tho.

[christarazi]

LGTM, pending Louis's suggestion.

[twpayne]

ConformanceKind1.19 failure is #16938.

[twpayne]

test-me-please

Job 'Cilium-PR-K8s-GKE' failed and has not been observed before, so may be related to your PR:

Click to show.

Test Name

K8sLRPTests Checks local redirect policy LRP connectivity

Failure Output

FAIL: Expected

If it is a flake, comment /mlh new-flake Cilium-PR-K8s-GKE so I can create a new GitHub issue to track it.

Job 'Cilium-PR-K8s-1.16-net-next' failed and has not been observed before, so may be related to your PR:

Click to show.

Test Name

K8sServicesTest Checks service across nodes Tests NodePort BPF Tests with direct routing Tests LoadBalancer Connectivity to endpoint via LB

Failure Output

FAIL: Can not connect to service "http://192.168.1.146" from outside cluster (1/10)

If it is a flake, comment /mlh new-flake Cilium-PR-K8s-1.16-net-next so I can create a new GitHub issue to track it.

[kaworu]

sed -i is not portable, but it seems we already use it in several places so let it be.

[twpayne]

test-me-please

[twpayne]

This needs #17391 and a rebase before the tests will pass as the current Vagrant box images have Go 1.16.

[twpayne]

Correction: #17352 #17394 is needed.

[twpayne]

/test