From e279f595adc8b5b1bfcfe06e2ae7581618115474 Mon Sep 17 00:00:00 2001
From: William Lallemand <wlallemand@haproxy.org>
Date: Thu, 11 May 2023 21:08:38 +0200
Subject: [PATCH] MINOR: httpclient: allow to disable the DNS resolvers of the
 httpclient

httpclient.resolvers.disabled allow to disable completely the resolvers
of the httpclient, prevents the creation of the "default" resolvers
section, and does not insert the http do-resolve rule in the proxies.
---
 doc/configuration.txt |  7 +++++++
 src/http_client.c     | 25 +++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 1ccc91b04..aabbe8e2b 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1068,6 +1068,7 @@ The following keywords are supported in the "global" section :
    - h1-case-adjust-file
    - h2-workaround-bogus-websocket-clients
    - hard-stop-after
+   - httpclient.resolvers.disabled
    - httpclient.resolvers.id
    - httpclient.resolvers.prefer
    - httpclient.ssl.ca-file
@@ -1681,6 +1682,12 @@ hard-stop-after <time>
 
   See also: grace
 
+httpclient.resolvers.disabled <on|off>
+  Disable the DNS resolution of the httpclient. Prevent the creation of the
+  "default" resolvers section.
+
+  Default value is off.
+
 httpclient.resolvers.id <resolvers id>
   This option defines the resolvers section with which the httpclient will try
   to resolve.
diff --git a/src/http_client.c b/src/http_client.c
index af30c8e58..2c33c85a2 100644
--- a/src/http_client.c
+++ b/src/http_client.c
@@ -53,6 +53,7 @@ static struct applet httpclient_applet;
 static int hard_error_resolvers = 0;
 static char *resolvers_id = NULL;
 static char *resolvers_prefer = NULL;
+static int resolvers_disabled = 0;
 
 /* --- This part of the file implement an HTTP client over the CLI ---
  * The functions will be  starting by "hc_cli" for "httpclient cli"
@@ -1138,6 +1139,10 @@ static int httpclient_resolve_init(struct proxy *px)
 	       { "" }
 	};
 
+
+	if (resolvers_disabled)
+		return 0;
+
 	if (!resolvers_id)
 		resolvers_id = strdup("default");
 
@@ -1432,6 +1437,25 @@ static int httpclient_parse_global_resolvers(char **args, int section_type, stru
 	return 0;
 }
 
+/* config parser for global "httpclient.resolvers.disabled", accepts "on" or "off" */
+static int httpclient_parse_global_resolvers_disabled(char **args, int section_type, struct proxy *curpx,
+                                      const struct proxy *defpx, const char *file, int line,
+                                      char **err)
+{
+	if (too_many_args(1, args, err, NULL))
+		return -1;
+
+	if (strcmp(args[1], "on") == 0)
+		resolvers_disabled = 1;
+	else if (strcmp(args[1], "off") == 0)
+		resolvers_disabled = 0;
+	else {
+		memprintf(err, "'%s' expects either 'on' or 'off' but got '%s'.", args[0], args[1]);
+		return -1;
+	}
+	return 0;
+}
+
 static int httpclient_parse_global_prefer(char **args, int section_type, struct proxy *curpx,
                                         const struct proxy *defpx, const char *file, int line,
                                         char **err)
@@ -1497,6 +1521,7 @@ static int httpclient_parse_global_verify(char **args, int section_type, struct
 #endif /* ! USE_OPENSSL */
 
 static struct cfg_kw_list cfg_kws = {ILH, {
+	{ CFG_GLOBAL, "httpclient.resolvers.disabled", httpclient_parse_global_resolvers_disabled },
 	{ CFG_GLOBAL, "httpclient.resolvers.id", httpclient_parse_global_resolvers },
 	{ CFG_GLOBAL, "httpclient.resolvers.prefer", httpclient_parse_global_prefer },
 #ifdef USE_OPENSSL