MINOR: acl: add the new "env()" fetch method to retrieve an environment variable
This is useful in order to take different actions across restarts without
touching the configuration (eg: soft-stop), or to pass some information
such as the local host name to the next hop.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 93437bb..0fa3b62 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -8795,6 +8795,20 @@
then this fetch clearly does not make sense, in which case the value returned
will be -1.
+env(<name>) : string
+ Returns a string containing the value of environment variable <name>. As a
+ reminder, environment variables are per-process and are sampled when the
+ process starts. This can be useful to pass some information to a next hop
+ server, or with ACLs to take specific action when the process is started a
+ certain way.
+
+ Examples :
+ # Pass the Via header to next hop with the local hostname in it
+ http-request add-header Via 1.1\ %[env(HOSTNAME)]
+
+ # reject cookie-less requests when the STOP environment variable is set
+ http-request deny if !{ cook(SESSIONID) -m found } { env(STOP) -m found }
+
fe_conn([<frontend>]) : integer
Returns the number of currently established connections on the frontend,
possibly including the connection being evaluated. If no frontend name is
diff --git a/src/acl.c b/src/acl.c
index f2abd44..26c0ac8 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -1980,6 +1980,26 @@
return 1;
}
+/* retrieve environment variable $1 as a string */
+static int
+smp_fetch_env(struct proxy *px, struct session *s, void *l7, unsigned int opt,
+ const struct arg *args, struct sample *smp)
+{
+ char *env;
+
+ if (!args || args[0].type != ARGT_STR)
+ return 0;
+
+ env = getenv(args[0].data.str.str);
+ if (!env)
+ return 0;
+
+ smp->type = SMP_T_CSTR;
+ smp->data.str.str = env;
+ smp->data.str.len = strlen(env);
+ return 1;
+}
+
/************************************************************************/
/* All supported sample and ACL keywords must be declared here. */
@@ -1991,8 +2011,9 @@
* instance IPv4/IPv6 must be declared IPv4.
*/
static struct sample_fetch_kw_list smp_kws = {{ },{
- { "always_false", smp_fetch_false, 0, NULL, SMP_T_BOOL, SMP_USE_INTRN },
- { "always_true", smp_fetch_true, 0, NULL, SMP_T_BOOL, SMP_USE_INTRN },
+ { "always_false", smp_fetch_false, 0, NULL, SMP_T_BOOL, SMP_USE_INTRN },
+ { "always_true", smp_fetch_true, 0, NULL, SMP_T_BOOL, SMP_USE_INTRN },
+ { "env", smp_fetch_env, ARG1(1,STR), NULL, SMP_T_CSTR, SMP_USE_INTRN },
{ /* END */ },
}};