resource: handle expiration update in resource.acquire response

Problem: Fluxion currently does not support expiration updates as
indicated by an expiration key in RFC 28 resource.acquire responses.

Add support for the expiration key in the resource.acquire response and
extend the graph duration using the new expiration as the graph_end.

Author: grondo

resource/modules/resource_match.cpp

@@ -1236,13 +1236,15 @@ static void update_resource (flux_future_t *f, void *arg)
     int rc = -1;
     const char *up = NULL;
     const char *down = NULL;
+    double expiration = -1.;
     json_t *resources = NULL;
     std::shared_ptr<resource_ctx_t> ctx = getctx ((flux_t *)arg);
 
-    if ( (rc = flux_rpc_get_unpack (f, "{s?:o s?:s s?:s}",
+    if ( (rc = flux_rpc_get_unpack (f, "{s?:o s?:s s?:s s?:F}",
                                            "resources", &resources,
                                            "up", &up,
-                                           "down", &down)) < 0) {
+                                           "down", &down,
+                                           "expiration", &expiration)) < 0) {
         flux_log_error (ctx->h, "%s: exiting due to resource.acquire failure",
                         __FUNCTION__);
         flux_reactor_stop (flux_get_reactor (ctx->h));
@@ -1252,6 +1254,12 @@ static void update_resource (flux_future_t *f, void *arg)
         flux_log_error (ctx->h, "%s: update_resource_db", __FUNCTION__);
         goto done;
     }
+    if (expiration >= 0.) {
+        /*  Update graph duration:
+         */
+        ctx->db->metadata.graph_duration.graph_end =
+            std::chrono::system_clock::from_time_t ((time_t) expiration);
+    }
     for (auto &kv : ctx->notify_msgs) {
         if ( (rc += flux_respond (ctx->h, kv.second->get_msg (), NULL)) < 0) {
             flux_log_error (ctx->h, "%s: flux_respond", __FUNCTION__);