MINOR: cli: filter the list of commands to the matching part

The error message on the CLI has become unreadable due to the long list
and it's not even sorted, making it even harder to figure the right
command.

This patch starts by looking if some of the words match something known,
and if so, will limit the listing only to those commands that start like
the current one. The "help", "prompt" and "quit" commands are always
shown to help the user try something else. Now thanks to this, typing
"add" or "del" will only list "add acl", "add map" and not 50 lines
anymore.

As a small bonus, we won't print "Unknown command" anymore in response
to the "help" command.

diff --git a/src/cli.c b/src/cli.c
index f4aefaf4e89bc0e30938cd6804f6f7b4769bfaca..027272611f0b526ecaab10afb3959ef69b0bf0c0 100644 (file)
--- a/src/cli.c
+++ b/src/cli.c
@@ -68,13 +68,6 @@
 static struct applet cli_applet;
 static struct applet mcli_applet;
 
-static const char stats_sock_usage_msg[] =
-       "Unknown command. Please enter one of the following commands only :\n"
-       "  help           : this message\n"
-       "  prompt         : toggle interactive mode with prompt\n"
-       "  quit           : disconnect\n"
-       "";
-
 static const char stats_permission_denied_msg[] =
        "Permission denied\n"
        "";
@@ -91,20 +84,54 @@ extern const char *stat_status_codes[];
 
 static struct proxy *mworker_proxy; /* CLI proxy of the master */
 
-static char *cli_gen_usage_msg(struct appctx *appctx)
+/* This will show the help message and list the commands supported at the
+ * current level that match all of the first words of <args> if args is not
+ * NULL, or all args if none matches or if args is null.
+ */
+static char *cli_gen_usage_msg(struct appctx *appctx, char * const *args)
 {
        struct cli_kw_list *kw_list;
        struct cli_kw *kw;
        struct buffer *tmp = get_trash_chunk();
        struct buffer out;
+       int idx;
+       int length = 0;
 
        ha_free(&dynamic_usage_msg);
 
-       if (LIST_ISEMPTY(&cli_keywords.list))
-               goto end;
+       /* first, let's measure the longest match */
+       list_for_each_entry(kw_list, &cli_keywords.list, list) {
+               for (kw = &kw_list->kw[0]; kw->str_kw[0]; kw++) {
+                       if (kw->level & ~appctx->cli_level & (ACCESS_MASTER_ONLY|ACCESS_EXPERT))
+                               continue;
+                       if ((appctx->cli_level & ~kw->level & (ACCESS_MASTER_ONLY|ACCESS_MASTER)) ==
+                           (ACCESS_MASTER_ONLY|ACCESS_MASTER))
+                               continue;
+
+                       /* OK this command is visible */
+                       for (idx = 0; idx < CLI_PREFIX_KW_NB; idx++) {
+                               if (!kw->str_kw[idx])
+                                       break; // end of keyword
+                               if (!args || !args[idx] || !*args[idx])
+                                       break; // end of command line
+                               if (strcmp(kw->str_kw[idx], args[idx]) != 0)
+                                       break;
+                               if (idx + 1 > length)
+                                       length = idx + 1;
+                       }
+               }
+       }
+
+       /* now <length> equals the number of matching words */
 
        chunk_reset(tmp);
-       chunk_strcat(tmp, stats_sock_usage_msg);
+       if (!args) // this is the help message.
+               chunk_strcat(tmp, "The following commands are valid at this level:\n");
+       else if (!length) // no match
+               chunk_strcat(tmp, "Unknown command. Please enter one of the following commands only:\n");
+       else // partial match
+               chunk_strcat(tmp, "Unknown command, but maybe one of the following ones is a better match:\n");
+
        list_for_each_entry(kw_list, &cli_keywords.list, list) {
                for (kw = &kw_list->kw[0]; kw->str_kw[0]; kw++) {
 
@@ -121,23 +148,32 @@ static char *cli_gen_usage_msg(struct appctx *appctx)
                            (ACCESS_MASTER_ONLY|ACCESS_MASTER))
                                continue;
 
-                       if (kw->usage)
+                       for (idx = 0; idx < length; idx++) {
+                               if (!kw->str_kw[idx])
+                                       break; // end of keyword
+                               if (!args || !args[idx] || !*args[idx])
+                                       break; // end of command line
+                               if (strcmp(kw->str_kw[idx], args[idx]) != 0)
+                                       break;
+                       }
+
+                       if (kw->usage && idx == length)
                                chunk_appendf(tmp, "  %s\n", kw->usage);
                }
        }
+
+       /* always show the prompt/help/quit commands */
+       chunk_strcat(tmp,
+                    "  help           : full commands list\n"
+                    "  prompt         : toggle interactive mode with prompt\n"
+                    "  quit           : disconnect\n");
+
        chunk_init(&out, NULL, 0);
        chunk_dup(&out, tmp);
        dynamic_usage_msg = out.area;
 
-end:
-       if (dynamic_usage_msg) {
-               appctx->ctx.cli.severity = LOG_INFO;
-               appctx->ctx.cli.msg = dynamic_usage_msg;
-       }
-       else {
-               appctx->ctx.cli.severity = LOG_INFO;
-               appctx->ctx.cli.msg = stats_sock_usage_msg;
-       }
+       appctx->ctx.cli.severity = LOG_INFO;
+       appctx->ctx.cli.msg = dynamic_usage_msg;
        appctx->st0 = CLI_ST_PRINT;
 
        return dynamic_usage_msg;
@@ -594,7 +630,7 @@ static int cli_parse_request(struct appctx *appctx)
            (kw->level & ~appctx->cli_level & ACCESS_MASTER_ONLY) ||
            (appctx->cli_level & ~kw->level & (ACCESS_MASTER_ONLY|ACCESS_MASTER)) == (ACCESS_MASTER_ONLY|ACCESS_MASTER)) {
                /* keyword not found in this mode */
-               cli_gen_usage_msg(appctx);
+               cli_gen_usage_msg(appctx, args);
                return 0;
        }
 
@@ -1879,7 +1915,7 @@ static int cli_parse_simple(char **args, char *payload, struct appctx *appctx, v
 {
        if (*args[0] == 'h')
                /* help */
-               cli_gen_usage_msg(appctx);
+               cli_gen_usage_msg(appctx, NULL);
        else if (*args[0] == 'p')
                /* prompt */
                appctx->st1 ^= APPCTX_CLI_ST1_PROMPT;