From: Willy Tarreau <w@1wt.eu>
Date: Tue, 15 Sep 2026 14:20:58 +0000 (+0200)
Subject: MINOR: extcheck: pass the master and worker IDs to external checks
X-Git-Tag: v3.5-dev7~6
X-Git-Url: https://git.kaiwu.me/?a=commitdiff_plain;h=a2e3bb6566398044d44ddba1f2bf768522dda481;p=haproxy.git

MINOR: extcheck: pass the master and worker IDs to external checks

By default, i.e. unless "external-check preserve-env" is used, the
environment of an external check is not inherited but entirely rebuilt
from the curated list in extcheck_envs[], so the two new identifiers
would not be visible from a check script. Let's add them there, next to
PATH, as a new process-scoped group before the proxy and server ones.
It's also cleaner because we pass the real directives, not the env
variables which could have been modified.
---

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 1f3a096d4..3b44d7592 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -8123,6 +8123,13 @@ external-check command <command>
   Some values are also provided through environment variables.
 
   Environment variables :
+    HAPROXY_MASTER_ID       The unique identifier of the master process, or
+                            empty when not running in master-worker mode. See
+                            section 2.3.
+
+    HAPROXY_WORKER_ID       The unique identifier of the worker process. See
+                            section 2.3 and the "worker-id" global keyword.
+
     HAPROXY_PROXY_ADDR      The first bind address if available (or empty if not
                             applicable, for example in a "backend" section).
 
diff --git a/src/extcheck.c b/src/extcheck.c
index 3d325eaf8..e19c30afc 100644
--- a/src/extcheck.c
+++ b/src/extcheck.c
@@ -63,6 +63,10 @@ struct extcheck_env {
 enum {
 	EXTCHK_PATH = 0,
 
+	/* Process specific environment variables */
+	EXTCHK_HAPROXY_MASTER_ID,	/* the master's unique ID (empty if no master) */
+	EXTCHK_HAPROXY_WORKER_ID,	/* the worker's unique ID */
+
 	/* Proxy specific environment variables */
 	EXTCHK_HAPROXY_PROXY_NAME,	/* the backend name */
 	EXTCHK_HAPROXY_PROXY_ID,	/* the backend id */
@@ -84,6 +88,8 @@ enum {
 
 const struct extcheck_env extcheck_envs[EXTCHK_SIZE] = {
 	[EXTCHK_PATH]                   = { "PATH",                   EXTCHK_SIZE_EVAL_INIT },
+	[EXTCHK_HAPROXY_MASTER_ID]      = { "HAPROXY_MASTER_ID",      EXTCHK_SIZE_EVAL_INIT },
+	[EXTCHK_HAPROXY_WORKER_ID]      = { "HAPROXY_WORKER_ID",      EXTCHK_SIZE_EVAL_INIT },
 	[EXTCHK_HAPROXY_PROXY_NAME]     = { "HAPROXY_PROXY_NAME",     EXTCHK_SIZE_EVAL_INIT },
 	[EXTCHK_HAPROXY_PROXY_ID]       = { "HAPROXY_PROXY_ID",       EXTCHK_SIZE_EVAL_INIT },
 	[EXTCHK_HAPROXY_PROXY_ADDR]     = { "HAPROXY_PROXY_ADDR",     EXTCHK_SIZE_EVAL_INIT },
@@ -331,6 +337,11 @@ int prepare_external_check(struct check *check)
 	}
 
 	EXTCHK_SETENV(check, EXTCHK_PATH, path, err);
+	/* Add process environment variables. The master's ID is empty when
+	 * there is no master, i.e. when not running in master-worker mode.
+	 */
+	EXTCHK_SETENV(check, EXTCHK_HAPROXY_MASTER_ID, global.master_id ? global.master_id : "", err);
+	EXTCHK_SETENV(check, EXTCHK_HAPROXY_WORKER_ID, global.worker_id ? global.worker_id : "", err);
 	/* Add proxy environment variables */
 	EXTCHK_SETENV(check, EXTCHK_HAPROXY_PROXY_NAME, px->id, err);
 	EXTCHK_SETENV(check, EXTCHK_HAPROXY_PROXY_ID, ultoa_r(px->uuid, buf, sizeof(buf)), err);