resource: ignore live resource.exclude changes

Problem: the resource module contains code to process live changes
to the configured exclude set, but there is no longer a use case
now that flux-batch(1) et al have a --conf option that can configure
exclusions on the command line for subinstances.

The extra code includes posting exclude/unexclude events to the KVS
resource.eventlog synchronously by calling the internal function
reslog_sync().  This makes the resource module unresponsive while
the KVS commit completes.

This extra complexity is no longer justified.  Remove.

src/modules/resource/acquire.c

@@ -350,7 +350,6 @@ static void reslog_cb (struct reslog *reslog, const char *name, void *arg)
             }
         }
         else if (streq (name, "online") || streq (name, "offline")
-                || streq (name, "exclude") || streq (name, "unexclude")
                 || streq (name, "drain") || streq (name, "undrain")) {
             if (ar->response_count > 0) {
                 struct idset *up, *dn;

src/modules/resource/exclude.c

@@ -8,9 +8,7 @@
  * SPDX-License-Identifier: LGPL-3.0
 \************************************************************/
 
-/* exclude.c - maintain a list of exec targets excluded from scheduling
- *
- * Post exclude/unexclude event when configured exclusion set changes.
+/* exclude.c - get static list of exec targets excluded from scheduling
  *
  * Caveats:
  * - There is no way to exclude at a finer granularity than execution target
@@ -43,74 +41,6 @@ const struct idset *exclude_get (struct exclude *exclude)
     return exclude->idset;
 }
 
-/* Update exclusion set and post event.
- */
-int exclude_update (struct exclude *exclude,
-                    const char *s,
-                    flux_error_t *errp)
-{
-    flux_t *h = exclude->ctx->h;
-    struct idset *idset = NULL;
-    struct idset *add;
-    struct idset *del;
-
-    if (s) {
-        if (!(idset = inventory_targets_to_ranks (exclude->ctx->inventory,
-                                                  s,
-                                                  errp)))
-            return -1;
-        if (idset_count (idset) > 0
-            && idset_last (idset) >= exclude->ctx->size) {
-            errprintf (errp, "exclusion idset is out of range");
-            idset_destroy (idset);
-            errno = EINVAL;
-            return -1;
-        }
-    }
-    if (rutil_idset_diff (exclude->idset, idset, &add, &del) < 0) {
-        errprintf (errp, "error analyzing exclusion set update");
-        idset_destroy (idset);
-        return -1;
-    }
-    if (add) {
-        char *add_s = idset_encode (add, IDSET_FLAG_RANGE);
-        if (!add_s || reslog_post_pack (exclude->ctx->reslog,
-                                        NULL,
-                                        0.,
-                                        "exclude",
-                                        "{s:s}",
-                                        "idset",
-                                        add_s) < 0) {
-            flux_log_error (h, "error posting exclude event");
-        }
-        /*  Added exclude ranks can no longer be drained:
-         */
-        if (undrain_ranks (exclude->ctx->drain, add) < 0)
-            flux_log_error (h,
-                            "exclude: failed to undrain ranks in %s",
-                            add_s);
-        free (add_s);
-        idset_destroy (add);
-    }
-    if (del) {
-        char *del_s = idset_encode (del, IDSET_FLAG_RANGE);
-        if (!del_s || reslog_post_pack (exclude->ctx->reslog,
-                                        NULL,
-                                        0.,
-                                        "unexclude",
-                                        "{s:s}",
-                                        "idset",
-                                        del_s) < 0) {
-            flux_log_error (h, "error posting unexclude event");
-        }
-        free (del_s);
-        idset_destroy (del);
-    }
-    idset_destroy (exclude->idset);
-    exclude->idset = idset;
-    return 0;
-}
-
 void exclude_destroy (struct exclude *exclude)
 {
     if (exclude) {

src/modules/resource/exclude.h

@@ -14,10 +14,6 @@
 struct exclude *exclude_create (struct resource_ctx *ctx, const char *idset);
 void exclude_destroy (struct exclude *exclude);
 
-int exclude_update (struct exclude *exclude,
-                    const char *idset,
-                    flux_error_t *errp);
-
 const struct idset *exclude_get (struct exclude *exclude);
 
 #endif /* !_FLUX_RESOURCE_EXCLUDE_H */

src/modules/resource/resource.c

@@ -116,7 +116,8 @@ static int parse_config (struct resource_ctx *ctx,
             return -1;
         }
     }
-    *excludep = exclude;
+    if (excludep)
+        *excludep = exclude;
     if (noverifyp)
         *noverifyp = noverify ? true : false;
     if (norestrictp)
@@ -130,9 +131,7 @@ static int parse_config (struct resource_ctx *ctx,
 
 /* Broker is sending us a new config object because 'flux config reload'
  * was run.  Parse it and respond with human readable errors.
- * If events are posted, block until they complete so that:
- * - any KVS commit errors are captured by 'flux config reload'
- * - tests can look for eventlog entry after running 'flux config reload'
+ * At the moment this doesn't do much - just cache the new config.
  */
 static void config_reload_cb (flux_t *h,
                               flux_msg_handler_t *mh,
@@ -141,34 +140,15 @@ static void config_reload_cb (flux_t *h,
 {
     struct resource_ctx *ctx = arg;
     const flux_conf_t *conf;
-    const char *exclude;
     flux_error_t error;
     const char *errstr = NULL;
 
     if (flux_conf_reload_decode (msg, &conf) < 0)
         goto error;
-    if (parse_config (ctx,
-                      conf,
-                      &exclude,
-                      NULL,
-                      NULL,
-                      NULL,
-                      &error) < 0) {
+    if (parse_config (ctx, conf, NULL, NULL, NULL, NULL, &error) < 0) {
         errstr = error.text;
         goto error;
     }
-    if (ctx->rank == 0) {
-        if (exclude_update (ctx->exclude,
-                            exclude,
-                            &error) < 0) {
-            errstr = error.text;
-            goto error;
-        }
-        if (reslog_sync (ctx->reslog) < 0) {
-            errstr = "error posting to eventlog for reconfig";
-            goto error;
-        }
-    }
     if (flux_set_conf (h, flux_conf_incref (conf)) < 0) {
         errstr = "error updating cached configuration";
         goto error;