From 589c0d73834d86396bbd0b29d05c84b8b8e04358 Mon Sep 17 00:00:00 2001
From: Christophe Fergeau <cfergeau@redhat.com>
Date: Wed, 24 Nov 2021 17:11:03 +0100
Subject: [PATCH] daemon: Re-read hosts file for each request

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the parsed hostfile is no longer valid, and adding more data to it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
https://github.com/code-ready/admin-helper/pull/23#issuecomment-971141415

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.
---
 cmd/admin-helper/daemon.go |  8 +-------
 pkg/api/mux.go             |  2 +-
 pkg/api/mux_test.go        |  2 +-
 pkg/hosts/hosts.go         | 24 ++++++++++++++++++++++++
 4 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/cmd/admin-helper/daemon.go b/cmd/admin-helper/daemon.go
index 4a90d5b3..c17d3901 100644
--- a/cmd/admin-helper/daemon.go
+++ b/cmd/admin-helper/daemon.go
@@ -5,7 +5,6 @@ import (
 	"net/http"
 
 	"github.com/code-ready/admin-helper/pkg/api"
-	"github.com/code-ready/admin-helper/pkg/hosts"
 	"github.com/kardianos/service"
 	"github.com/spf13/cobra"
 )
@@ -80,12 +79,7 @@ func (p *program) Start(s service.Service) error {
 			_ = logger.Error(err)
 			return
 		}
-		hosts, err := hosts.New()
-		if err != nil {
-			_ = logger.Error(err)
-			return
-		}
-		if err := http.Serve(ln, api.Mux(hosts)); err != nil {
+		if err := http.Serve(ln, api.Mux()); err != nil {
 			_ = logger.Error(err)
 			return
 		}
diff --git a/pkg/api/mux.go b/pkg/api/mux.go
index 034427b1..018a7cfc 100644
--- a/pkg/api/mux.go
+++ b/pkg/api/mux.go
@@ -10,7 +10,7 @@ import (
 	"github.com/code-ready/admin-helper/pkg/types"
 )
 
-func Mux(hosts *hosts.Hosts) http.Handler {
+func Mux() http.Handler {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
 		_, _ = fmt.Fprint(w, constants.Version)
diff --git a/pkg/api/mux_test.go b/pkg/api/mux_test.go
index 306a3264..3a3a3fe4 100644
--- a/pkg/api/mux_test.go
+++ b/pkg/api/mux_test.go
@@ -11,7 +11,7 @@ import (
 )
 
 func TestMux(t *testing.T) {
-	ts := httptest.NewServer(Mux(nil))
+	ts := httptest.NewServer(Mux())
 	defer ts.Close()
 
 	client := client.New(http.DefaultClient, ts.URL)
diff --git a/pkg/hosts/hosts.go b/pkg/hosts/hosts.go
index 16a2b823..41f09b30 100644
--- a/pkg/hosts/hosts.go
+++ b/pkg/hosts/hosts.go
@@ -43,6 +43,14 @@ func defaultFilter(s string) bool {
 	return clusterRegexp.MatchString(s) || appRegexp.MatchString(s)
 }
 
+func Add(ip string, hosts []string) error {
+	h, err := New()
+	if err != nil {
+		return err
+	}
+	return h.Add(ip, hosts)
+}
+
 func (h *Hosts) Add(ip string, hosts []string) error {
 	if err := h.verifyHosts(hosts); err != nil {
 		return err
@@ -75,6 +83,14 @@ func (h *Hosts) Add(ip string, hosts []string) error {
 	return h.File.Flush()
 }
 
+func Remove(hosts []string) error {
+	h, err := New()
+	if err != nil {
+		return err
+	}
+	return h.Remove(hosts)
+}
+
 func (h *Hosts) Remove(hosts []string) error {
 	if err := h.verifyHosts(hosts); err != nil {
 		return err
@@ -102,6 +118,14 @@ func (h *Hosts) Remove(hosts []string) error {
 	return h.File.Flush()
 }
 
+func Clean(rawSuffixes []string) error {
+	h, err := New()
+	if err != nil {
+		return err
+	}
+	return h.Clean(rawSuffixes)
+}
+
 func (h *Hosts) Clean(rawSuffixes []string) error {
 	if err := h.checkIsWritable(); err != nil {
 		return err