daemon: Re-read hosts file for each request

[cfergeau]

This is quite wasteful, but after hostsfile.Clean() has been called,
the parsed hostfile is no longer valid, and adding more data to it
causes some of its content to disappear, see
#23 (comment)

This issue can only be seen when the admin-helper daemon is used, and
when there's a limit to the number of entries per line, which means this
can only be reproduced on Windows.

By reparsing the hostfile each time we get a request, we workaround this
bug.

[praveenkumar]

@cfergeau unit test fails which need update

# github.com/code-ready/admin-helper/pkg/api [github.com/code-ready/admin-helper/pkg/api.test]
pkg\api\mux_test.go:14:30: too many arguments in call to Mux
	have (nil)
	want ()
note: module requires Go 1.15
FAIL	github.com/code-ready/admin-helper/pkg/api [build failed]

[gbraad]

I'll take a look at this.

The process on Windows is long-running and likely gets out of sync.

[cfergeau]

An alternative fix (did not test it) is:

diff --git a/pkg/hosts/hosts.go b/pkg/hosts/hosts.go
index 16a2b82..b956dc2 100644
--- a/pkg/hosts/hosts.go
+++ b/pkg/hosts/hosts.go
@@ -71,6 +71,12 @@ func (h *Hosts) Add(ip string, hosts []string) error {
        // 9 domain entry in a single line
        if runtime.GOOS == "windows" {
                h.File.Clean()
+               h.File.Flush()
+               file, err := hostsfile.NewHosts()
+               if err != nil {
+                       return err
+               }
+               h.File = &file
        }
        return h.File.Flush()
 }

[praveenkumar]

👍🏼