BUG/MEDIUM: stats: show servers state may show an empty or incomplete result

It was reported that the unix socket command "show servers state" returned an
empty response while "show servers state <backend>" worked.
In fact, both cases can reproduce the issue. It happens when the response can't
fit in one buffer.

The fix consists in processing the response in several steps, as it is done in
some others commands, by restarting where it was stopped after the buffer is
sent to the client.

This fix should be backported to haproxy 1.6

diff --git a/include/types/applet.h b/include/types/applet.h
index 562575f020d7de26094763cb0ad50657684c9226..bf801f41dcf76c02933bf8897f3b6ea09c167e89 100644 (file)
--- a/include/types/applet.h
+++ b/include/types/applet.h
@@ -131,7 +131,9 @@ struct appctx {
                        struct dns_resolvers *ptr;
                } resolvers;
                struct {
-                       struct proxy *backend;
+                       int iid;                /* if >= 0, ID of the proxy to filter on */
+                       struct proxy *px;       /* current proxy being dumped, NULL = not started yet. */
+                       struct server *sv;      /* current server being dumped, NULL = not started yet. */
                } server_state;
                struct {
                        char **var;

diff --git a/src/dumpstats.c b/src/dumpstats.c
index bfd5b5cddbe0c47f46316e52ecdebb0cb6aa76be..a6d021bfc215369d6d66e69c75eb0b85eb3a24fa 100644 (file)
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -303,7 +303,7 @@ static int stats_tlskeys_list(struct stream_interface *si);
 #endif
 static void cli_release_handler(struct appctx *appctx);
 
-static void dump_servers_state(struct proxy *backend, struct chunk *buf);
+static int dump_servers_state(struct stream_interface *si, struct chunk *buf);
 
 /*
  * cli_io_handler()
@@ -1379,18 +1379,21 @@ static int stats_sock_parse_request(struct stream_interface *si, char *line)
                        appctx->st0 = STAT_CLI_O_INFO; // stats_dump_info_to_buffer
                }
                else if (strcmp(args[1], "servers") == 0 && strcmp(args[2], "state") == 0) {
-                       appctx->ctx.server_state.backend = NULL;
+                       appctx->ctx.server_state.iid = 0;
+                       appctx->ctx.server_state.px = NULL;
+                       appctx->ctx.server_state.sv = NULL;
 
                        /* check if a backend name has been provided */
                        if (*args[3]) {
                                /* read server state from local file */
-                               appctx->ctx.server_state.backend = proxy_be_by_name(args[3]);
+                               appctx->ctx.server_state.px = proxy_be_by_name(args[3]);
 
-                               if (appctx->ctx.server_state.backend == NULL) {
+                               if (!appctx->ctx.server_state.px) {
                                        appctx->ctx.cli.msg = "Can't find backend.\n";
                                        appctx->st0 = STAT_CLI_PRINT;
                                        return 1;
                                }
+                               appctx->ctx.server_state.iid = appctx->ctx.server_state.px->uuid;
                        }
                        appctx->st2 = STAT_ST_INIT;
                        appctx->st0 = STAT_CLI_O_SERVERS_STATE; // stats_dump_servers_state_to_buffer
@@ -3057,20 +3060,21 @@ static int stats_dump_info_to_buffer(struct stream_interface *si)
  * By default, we only export to the last known server state file format.
  * These information can be used at next startup to recover same level of server state.
  */
-static void dump_servers_state(struct proxy *backend, struct chunk *buf)
+static int dump_servers_state(struct stream_interface *si, struct chunk *buf)
 {
+       struct appctx *appctx = __objt_appctx(si->end);
        struct server *srv;
        char srv_addr[INET6_ADDRSTRLEN + 1];
        time_t srv_time_since_last_change;
        int bk_f_forced_id, srv_f_forced_id;
 
-       /* we don't want to report any state if the backend is not enabled on this process */
-       if (backend->bind_proc && !(backend->bind_proc & (1UL << (relative_pid - 1))))
-               return;
 
-       srv = backend->srv;
+       /* we don't want to report any state if the backend is not enabled on this process */
+       if (appctx->ctx.server_state.px->bind_proc && !(appctx->ctx.server_state.px->bind_proc & (1UL << (relative_pid - 1))))
+               return 1;
 
-       while (srv) {
+       for (; appctx->ctx.server_state.sv != NULL; appctx->ctx.server_state.sv = srv->next) {
+               srv = appctx->ctx.server_state.sv;
                srv_addr[0] = '\0';
                srv_time_since_last_change = 0;
                bk_f_forced_id = 0;
@@ -3087,7 +3091,7 @@ static void dump_servers_state(struct proxy *backend, struct chunk *buf)
                                break;
                }
                srv_time_since_last_change = now.tv_sec - srv->last_change;
-               bk_f_forced_id = backend->options & PR_O_FORCED_ID ? 1 : 0;
+               bk_f_forced_id = appctx->ctx.server_state.px->options & PR_O_FORCED_ID ? 1 : 0;
                srv_f_forced_id = srv->flags & SRV_F_FORCED_ID ? 1 : 0;
 
                chunk_appendf(buf,
@@ -3097,14 +3101,17 @@ static void dump_servers_state(struct proxy *backend, struct chunk *buf)
                                "%d %d %d %d %d "
                                "%d %d"
                                "\n",
-                               backend->uuid, backend->id,
+                               appctx->ctx.server_state.px->uuid, appctx->ctx.server_state.px->id,
                                srv->puid, srv->id, srv_addr,
                                srv->state, srv->admin, srv->uweight, srv->iweight, (long int)srv_time_since_last_change,
                                srv->check.status, srv->check.result, srv->check.health, srv->check.state, srv->agent.state,
                                bk_f_forced_id, srv_f_forced_id);
-
-               srv = srv->next;
+               if (bi_putchk(si_ic(si), &trash) == -1) {
+                       si_applet_cant_put(si);
+                       return 0;
+               }
        }
+       return 1;
 }
 
 /* Parses backend list and simply report backend names */
@@ -3147,24 +3154,32 @@ static int stats_dump_servers_state_to_buffer(struct stream_interface *si)
 
        chunk_reset(&trash);
 
-       chunk_printf(&trash, "%d\n# %s\n", SRV_STATE_FILE_VERSION, SRV_STATE_FILE_FIELD_NAMES);
-
-       if (appctx->ctx.server_state.backend) {
-               dump_servers_state(appctx->ctx.server_state.backend, &trash);
-       }
-       else {
-               for (curproxy = proxy; curproxy != NULL; curproxy = curproxy->next) {
-                       /* servers are only in backends */
-                       if (!(curproxy->cap & PR_CAP_BE))
-                               continue;
-
-                       dump_servers_state(curproxy, &trash);
+       if (!appctx->ctx.server_state.px) {
+               chunk_printf(&trash, "%d\n# %s\n", SRV_STATE_FILE_VERSION, SRV_STATE_FILE_FIELD_NAMES);
+               if (bi_putchk(si_ic(si), &trash) == -1) {
+                       si_applet_cant_put(si);
+                       return 0;
                }
+               appctx->ctx.server_state.px = proxy;
        }
 
-       if (bi_putchk(si_ic(si), &trash) == -1) {
-               si_applet_cant_put(si);
-               return 0;
+       for (; appctx->ctx.server_state.px != NULL; appctx->ctx.server_state.px = curproxy->next) {
+               curproxy = appctx->ctx.server_state.px;
+               if (!appctx->ctx.server_state.sv)
+                       appctx->ctx.server_state.sv = appctx->ctx.server_state.px->srv;
+               /* servers are only in backends */
+               if (curproxy->cap & PR_CAP_BE) {
+                       if (!dump_servers_state(si, &trash))
+                               return 0;
+
+                       if (bi_putchk(si_ic(si), &trash) == -1) {
+                               si_applet_cant_put(si);
+                               return 0;
+                       }
+               }
+               /* only the selected proxy is dumped */
+               if (appctx->ctx.server_state.iid)
+                       break;
        }
 
        return 1;