dev: make command errors

[somaritane]

When kube config context is empty or pointing to another cluster or cluster without k8gb installed, make commands are failing:

 ❯ make                                
The connection to the server localhost:8080 was refused - did you specify the right host or port?
...

❯ make                                           
Error from server (NotFound): namespaces "k8gb" not found

This happens during the evaluation of the K8GB_COREDNS_IP make var:

k8gb/Makefile

Line 38 in 367e007

K8GB_COREDNS_IP ?= $(shell kubectl get svc k8gb-coredns -n k8gb -o custom-columns='IP:spec.clusterIP' --no-headers)

Also make demo command fails in any case:

make demo
/bin/sh: K8GB_COREDNS_IP: command not found

Most probably a regression by #764

[k0da]

This is weird and shouldn't happen:

FILES := $(shell ...)  # expand now; FILES is now the result of $(shell ...)

FILES = $(shell ...)   # expand later: FILES holds the syntax $(shell ...)

[k0da]

 make -version
GNU Make 4.3
Built for x86_64-apple-darwin20.1.0
Copyright (C) 1988-2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

☸ cto-bcp-nonprod-270 in k8gb on  edge [$?] via 🐹 v1.17.1
13:11:25 ❯ make
check                     Check project integrity
demo                      Execute end-to-end demo
deploy-full-local-setup   Deploy full local multicluster setup (k3d >= 4.2.0)
deploy-gslb-operator      Deploy k8gb operator
deploy-test-apps          Deploy Podinfo (example app) and Apply Gslb Custom Resources
deploy-test-version       Upgrade k8gb to the test version on existing clusters
destroy-full-local-setup  Destroy full local multicluster setup
dns-tools                 Run temporary dnstools pod for debugging DNS issues
help                      Show this help

[somaritane]

@k0da just tried to repro the issue:

Try to create .env file and run make again.
When .env file is included and its vars are exported, then the error happens with K8GB_COREDNS_IP resolution.
If the export is omitted:
https://github.com/k8gb-io/k8gb/blob/master/Makefile#L21
Then these variables are not available to subshells.