Add support for HCTemplates to mod_lbmethod_cluster

Author: jajik

native/balancers/mod_lbmethod_cluster.c

@@ -6,7 +6,6 @@
 #include "mod_watchdog.h"
 #include "common.h"
 
-
 #define LB_CLUSTER_WATHCHDOG_NAME ("_lb_cluster_")
 static ap_watchdog_t *watchdog;
 
@@ -16,6 +15,9 @@ static struct context_storage_method *context_storage = NULL;
 static struct balancer_storage_method *balancer_storage = NULL;
 static struct domain_storage_method *domain_storage = NULL;
 
+static apr_table_t *proxyhctemplate;
+static void (*set_proxyhctemplate_f)(apr_pool_t *, apr_table_t *) = NULL;
+
 static int use_alias = 0; /* 1 : Compare Alias with server_name */
 static int use_nocanon = 0;
 static apr_time_t lbstatus_recalc_time =
@@ -362,6 +364,13 @@ static int lbmethod_cluster_post_config(apr_pool_t *p, apr_pool_t *plog, apr_poo
         ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, "proxy_cluster_post_config: Can't find mod_manager for domains");
         return !OK;
     }
+    set_proxyhctemplate_f = ap_lookup_provider("manager", "shared", "6");
+    if (set_proxyhctemplate_f == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                     "lbmethod_cluster_post_config: Can't find mod_manager for set_proxyhctemplate function");
+    } else if (!apr_is_empty_table(proxyhctemplate)) {
+        set_proxyhctemplate_f(p, proxyhctemplate);
+    }
 
     /* Add version information */
     ap_add_version_component(p, MOD_CLUSTER_EXPOSED_VERSION);
@@ -405,10 +414,30 @@ static const char *cmd_nocanon(cmd_parms *parms, void *mconfig, int on)
     return NULL;
 }
 
+static const char *cmd_proxyhctemplate(cmd_parms *cmd, void *dummy, const char *arg)
+{
+    const char *err = NULL;
+    (void)dummy;
+
+    if (!proxyhctemplate) {
+        proxyhctemplate = apr_table_make(cmd->pool, 8);
+    }
+
+    err = parse_proxyhctemplate_params(cmd->pool, arg, proxyhctemplate);
+    if (err != NULL) {
+        return err;
+    }
+    return NULL;
+}
+
 static const command_rec lbmethod_cmds[] = {
     AP_INIT_FLAG("UseNocanon", cmd_nocanon, NULL, OR_ALL,
                  "UseNocanon - When no ProxyPass or ProxyMatch for the URL, passes the URL path \"raw\" to the backend "
-                 "(Default: Off)")};
+                 "(Default: Off)"),
+    AP_INIT_RAW_ARGS(
+        "ModProxyClusterHCTemplate", cmd_proxyhctemplate, NULL, OR_ALL,
+        "ModProxyClusterHCTemplate - Set of health check parameters to use with mod_lbmethod_cluster workers."),
+    {NULL}};
 
 static void register_hooks(apr_pool_t *p)
 {

native/common/common.c

@@ -670,3 +670,19 @@ const node_context *context_host_ok(request_rec *r, const proxy_balancer *balanc
 
     return best->node != -1 ? best : NULL;
 }
+
+const char *parse_proxyhctemplate_params(apr_pool_t *pool, const char *arg, apr_table_t *params)
+{
+    while (*arg) {
+        char *key, *val;
+        key = ap_getword_conf(pool, &arg);
+        val = strchr(key, '=');
+        if (!val) {
+            return "Invalid ProxyHCTemplate parameter. Parameter must be in the form 'key=value'";
+        }
+        *val++ = '\0';
+
+        apr_table_add(params, key, val);
+    }
+    return NULL;
+}

native/include/balancer.h

@@ -143,4 +143,10 @@ struct balancer_storage_method
      */
     int (*get_max_size_balancer)(void);
 };
+
+/**
+ * Helper function for translating hcheck template parameters to corresponding balancer parameters
+ */
+const char *translate_balancer_params(const char *param);
+
 #endif /*BALANCER_H*/

native/include/common.h

@@ -7,7 +7,6 @@
  * Common routines
  */
 
-
 #include "mod_proxy_cluster.h"
 
 
@@ -17,7 +16,6 @@ struct counter
     int *values;
 };
 
-
 /**
  * Read the virtual host table from shared memory
  * @param pool pool to use for memory allocation
@@ -222,3 +220,9 @@ apr_status_t loc_get_id(void *mem, void *data, apr_pool_t *pool);
 const node_context *context_host_ok(request_rec *r, const proxy_balancer *balancer, int node, int use_alias,
                                     const proxy_vhost_table *vhost_table, const proxy_context_table *context_table,
                                     const proxy_node_table *node_table);
+
+/**
+ * Parse ProxyHCTemplate parameters from @param arg into @param params using @param pool for allocations
+ * @return error message or NULL if everything went well
+ */
+const char *parse_proxyhctemplate_params(apr_pool_t *pool, const char *arg, apr_table_t *params);

native/mod_manager/balancer.c

@@ -174,3 +174,27 @@ mem_t *create_mem_balancer(char *string, unsigned *num, int persist, apr_pool_t
 {
     return create_attach_mem_balancer(string, num, persist, 1, p, storage);
 }
+
+const char *translate_balancer_params(const char *param)
+{
+    if (strcasecmp(param, "hcinterval") == 0) {
+        return "w_hi";
+    }
+    if (strcasecmp(param, "hcpasses") == 0) {
+        return "w_hp";
+    }
+    if (strcasecmp(param, "hcfails") == 0) {
+        return "w_hf";
+    }
+    if (strcasecmp(param, "hcmethod") == 0) {
+        return "w_hm";
+    }
+    if (strcasecmp(param, "hcuri") == 0) {
+        return "w_hu";
+    }
+    if (strcasecmp(param, "hcexpr") == 0) {
+        return "w_he";
+    }
+
+    return NULL;
+}

native/mod_manager/mod_manager.c

@@ -107,6 +107,13 @@ static mem_t *hoststatsmem = NULL;
 static mem_t *balancerstatsmem = NULL;
 static mem_t *sessionidstatsmem = NULL;
 static mem_t *domainstatsmem = NULL;
+/* Used for HCExpr templates with lbmethod_cluster */
+static apr_table_t *proxyhctemplate = NULL;
+
+static void set_proxyhctemplate(apr_pool_t *p, apr_table_t *t)
+{
+    proxyhctemplate = apr_table_overlay(p, t, proxyhctemplate);
+}
 
 static slotmem_storage_method *storage = NULL;
 static balancer_method *balancerhandler = NULL;
@@ -540,6 +547,7 @@ static int manager_pre_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *p
     (void)ptemp;
     ap_mutex_register(pconf, node_mutex_type, NULL, APR_LOCK_DEFAULT, 0);
     ap_mutex_register(pconf, context_mutex_type, NULL, APR_LOCK_DEFAULT, 0);
+    proxyhctemplate = apr_table_make(plog, 1);
     return OK;
 }
 
@@ -910,6 +918,11 @@ static int is_same_worker_existing(const request_rec *r, const nodeinfo_t *node)
 static apr_status_t mod_manager_manage_worker(request_rec *r, const nodeinfo_t *node, const balancerinfo_t *bal)
 {
     apr_table_t *params;
+    apr_status_t rv;
+    int i;
+    const apr_array_header_t *h;
+    const apr_table_entry_t *entries;
+
     params = apr_table_make(r->pool, 10);
     /* balancer */
     apr_table_set(params, "b", node->mess.balancer);
@@ -938,6 +951,17 @@ static apr_status_t mod_manager_manage_worker(request_rec *r, const nodeinfo_t *
 
     /* Use 10 sec for the moment, the idea is to adjust it with the STATUS frequency */
     apr_table_set(params, "w_hi", "10000");
+
+    h = apr_table_elts(proxyhctemplate);
+    entries = (const apr_table_entry_t *)h->elts;
+
+    for (i = 0; i < h->nelts; i++) {
+        const char *key = translate_balancer_params(entries[i].key);
+        if (key != NULL) {
+            apr_table_set(params, key, entries[i].val);
+        }
+    }
+
     return balancer_manage(r, params);
 }
 
@@ -3935,6 +3959,7 @@ static void manager_hooks(apr_pool_t *p)
     ap_register_provider(p, "manager", "shared", "3", &balancer_storage);
     ap_register_provider(p, "manager", "shared", "4", &sessionid_storage);
     ap_register_provider(p, "manager", "shared", "5", &domain_storage);
+    ap_register_provider(p, "manager", "shared", "6", &set_proxyhctemplate);
 }
 
 /*