[rrd-developers] [PATCH] rrdcached refactor command structures
kevin brintnall
kbrint at rufus.net
Fri Apr 10 08:42:38 CEST 2009
This patch consolidates several aspects of the command handling in
rrdcached:
* all commands, help, and context information is reduced to a single data
structure.
* all checks for command validity (context and permission) are handled in
the main dispatch routine
This removes duplicate help/syntax text, and long if..elseif..else chains.
It facilitates the addition of new commands.
---
diff --git a/src/rrd_daemon.c b/src/rrd_daemon.c
index 1e53175..dcca55d 100644
--- a/src/rrd_daemon.c
+++ b/src/rrd_daemon.c
@@ -144,6 +144,31 @@ struct listen_socket_s
};
typedef struct listen_socket_s listen_socket_t;
+struct command;
+/* note: guard against "unused" warnings in the handlers */
+#define DISPATCH_PROTO listen_socket_t *sock __attribute__((unused)),\
+ time_t now __attribute__((unused)),\
+ char *buffer __attribute__((unused)),\
+ size_t buffer_size __attribute__((unused))
+
+#define HANDLER_PROTO struct command *cmd __attribute__((unused)),\
+ DISPATCH_PROTO
+
+struct command {
+ char *cmd;
+ int (*handler)(HANDLER_PROTO);
+ socket_privilege min_priv;
+
+ char context; /* where we expect to see it */
+#define CMD_CONTEXT_CLIENT (1<<0)
+#define CMD_CONTEXT_BATCH (1<<1)
+#define CMD_CONTEXT_JOURNAL (1<<2)
+#define CMD_CONTEXT_ANY (0x7f)
+
+ char *syntax;
+ char *help;
+};
+
struct cache_item_s;
typedef struct cache_item_s cache_item_t;
struct cache_item_s
@@ -239,6 +264,9 @@ static int journal_write(char *cmd, char *args);
static void journal_done(void);
static void journal_rotate(void);
+/* prototypes for forward refernces */
+static int handle_request_help (HANDLER_PROTO);
+
/*
* Functions
*/
@@ -1067,166 +1095,17 @@ static int flush_file (const char *filename) /* {{{ */
return (0);
} /* }}} int flush_file */
-static int handle_request_help (listen_socket_t *sock, /* {{{ */
- char *buffer, size_t buffer_size)
+static int syntax_error(listen_socket_t *sock, struct command *cmd) /* {{{ */
{
- int status;
- char **help_text;
- char *command;
-
- char *help_help[2] =
- {
- "Command overview\n"
- ,
- "HELP [<command>]\n"
- "FLUSH <filename>\n"
- "FLUSHALL\n"
- "PENDING <filename>\n"
- "FORGET <filename>\n"
- "QUEUE\n"
- "UPDATE <filename> <values> [<values> ...]\n"
- "BATCH\n"
- "STATS\n"
- "QUIT\n"
- };
+ char *err = "Syntax error.\n";
- char *help_flush[2] =
- {
- "Help for FLUSH\n"
- ,
- "Usage: FLUSH <filename>\n"
- "\n"
- "Adds the given filename to the head of the update queue and returns\n"
- "after it has been dequeued.\n"
- };
+ if (cmd && cmd->syntax)
+ err = cmd->syntax;
- char *help_flushall[2] =
- {
- "Help for FLUSHALL\n"
- ,
- "Usage: FLUSHALL\n"
- "\n"
- "Triggers writing of all pending updates. Returns immediately.\n"
- };
+ return send_response(sock, RESP_ERR, "Usage: %s", err);
+} /* }}} static int syntax_error() */
- char *help_pending[2] =
- {
- "Help for PENDING\n"
- ,
- "Usage: PENDING <filename>\n"
- "\n"
- "Shows any 'pending' updates for a file, in order.\n"
- "The updates shown have not yet been written to the underlying RRD file.\n"
- };
-
- char *help_forget[2] =
- {
- "Help for FORGET\n"
- ,
- "Usage: FORGET <filename>\n"
- "\n"
- "Removes the file completely from the cache.\n"
- "Any pending updates for the file will be lost.\n"
- };
-
- char *help_queue[2] =
- {
- "Help for QUEUE\n"
- ,
- "Shows all files in the output queue.\n"
- "The output is zero or more lines in the following format:\n"
- "(where <num_vals> is the number of values to be written)\n"
- "\n"
- "<num_vals> <filename>\n"
- "\n"
- };
-
- char *help_update[2] =
- {
- "Help for UPDATE\n"
- ,
- "Usage: UPDATE <filename> <values> [<values> ...]\n"
- "\n"
- "Adds the given file to the internal cache if it is not yet known and\n"
- "appends the given value(s) to the entry. See the rrdcached(1) manpage\n"
- "for details.\n"
- "\n"
- "Each <values> has the following form:\n"
- " <values> = <time>:<value>[:<value>[...]]\n"
- "See the rrdupdate(1) manpage for details.\n"
- };
-
- char *help_stats[2] =
- {
- "Help for STATS\n"
- ,
- "Usage: STATS\n"
- "\n"
- "Returns some performance counters, see the rrdcached(1) manpage for\n"
- "a description of the values.\n"
- };
-
- char *help_batch[2] =
- {
- "Help for BATCH\n"
- ,
- "The 'BATCH' command permits the client to initiate a bulk load\n"
- " of commands to rrdcached.\n"
- "\n"
- "Usage:\n"
- "\n"
- " client: BATCH\n"
- " server: 0 Go ahead. End with dot '.' on its own line.\n"
- " client: command #1\n"
- " client: command #2\n"
- " client: ... and so on\n"
- " client: .\n"
- " server: 2 errors\n"
- " server: 7 message for command #7\n"
- " server: 9 message for command #9\n"
- "\n"
- "For more information, consult the rrdcached(1) documentation.\n"
- };
-
- char *help_quit[2] =
- {
- "Help for QUIT\n"
- ,
- "Disconnect from rrdcached.\n"
- };
-
- status = buffer_get_field (&buffer, &buffer_size, &command);
- if (status != 0)
- help_text = help_help;
- else
- {
- if (strcasecmp (command, "update") == 0)
- help_text = help_update;
- else if (strcasecmp (command, "flush") == 0)
- help_text = help_flush;
- else if (strcasecmp (command, "flushall") == 0)
- help_text = help_flushall;
- else if (strcasecmp (command, "pending") == 0)
- help_text = help_pending;
- else if (strcasecmp (command, "forget") == 0)
- help_text = help_forget;
- else if (strcasecmp (command, "queue") == 0)
- help_text = help_queue;
- else if (strcasecmp (command, "stats") == 0)
- help_text = help_stats;
- else if (strcasecmp (command, "batch") == 0)
- help_text = help_batch;
- else if (strcasecmp (command, "quit") == 0)
- help_text = help_quit;
- else
- help_text = help_help;
- }
-
- add_response_info(sock, help_text[1]);
- return send_response(sock, RESP_OK, help_text[0]);
-} /* }}} int handle_request_help */
-
-static int handle_request_stats (listen_socket_t *sock) /* {{{ */
+static int handle_request_stats (HANDLER_PROTO) /* {{{ */
{
uint64_t copy_queue_length;
uint64_t copy_updates_received;
@@ -1274,8 +1153,7 @@ static int handle_request_stats (listen_socket_t *sock) /* {{{ */
return (0);
} /* }}} int handle_request_stats */
-static int handle_request_flush (listen_socket_t *sock, /* {{{ */
- char *buffer, size_t buffer_size)
+static int handle_request_flush (HANDLER_PROTO) /* {{{ */
{
char *file, file_tmp[PATH_MAX];
int status;
@@ -1283,7 +1161,7 @@ static int handle_request_flush (listen_socket_t *sock, /* {{{ */
status = buffer_get_field (&buffer, &buffer_size, &file);
if (status != 0)
{
- return send_response(sock, RESP_ERR, "Usage: flush <filename>\n");
+ return syntax_error(sock,cmd);
}
else
{
@@ -1318,14 +1196,8 @@ static int handle_request_flush (listen_socket_t *sock, /* {{{ */
assert(1==0);
} /* }}} int handle_request_flush */
-static int handle_request_flushall(listen_socket_t *sock) /* {{{ */
+static int handle_request_flushall(HANDLER_PROTO) /* {{{ */
{
- int status;
-
- status = has_privilege(sock, PRIV_HIGH);
- if (status <= 0)
- return status;
-
RRDD_LOG(LOG_DEBUG, "Received FLUSHALL");
pthread_mutex_lock(&cache_lock);
@@ -1335,8 +1207,7 @@ static int handle_request_flushall(listen_socket_t *sock) /* {{{ */
return send_response(sock, RESP_OK, "Started flush.\n");
} /* }}} static int handle_request_flushall */
-static int handle_request_pending(listen_socket_t *sock, /* {{{ */
- char *buffer, size_t buffer_size)
+static int handle_request_pending(HANDLER_PROTO) /* {{{ */
{
int status;
char *file, file_tmp[PATH_MAX];
@@ -1344,12 +1215,7 @@ static int handle_request_pending(listen_socket_t *sock, /* {{{ */
status = buffer_get_field(&buffer, &buffer_size, &file);
if (status != 0)
- return send_response(sock, RESP_ERR,
- "Usage: PENDING <filename>\n");
-
- status = has_privilege(sock, PRIV_HIGH);
- if (status <= 0)
- return status;
+ return syntax_error(sock,cmd);
get_abs_path(&file, file_tmp);
@@ -1368,8 +1234,7 @@ static int handle_request_pending(listen_socket_t *sock, /* {{{ */
return send_response(sock, RESP_OK, "updates pending\n");
} /* }}} static int handle_request_pending */
-static int handle_request_forget(listen_socket_t *sock, /* {{{ */
- char *buffer, size_t buffer_size)
+static int handle_request_forget(HANDLER_PROTO) /* {{{ */
{
int status;
gboolean found;
@@ -1377,12 +1242,7 @@ static int handle_request_forget(listen_socket_t *sock, /* {{{ */
status = buffer_get_field(&buffer, &buffer_size, &file);
if (status != 0)
- return send_response(sock, RESP_ERR,
- "Usage: FORGET <filename>\n");
-
- status = has_privilege(sock, PRIV_HIGH);
- if (status <= 0)
- return status;
+ return syntax_error(sock,cmd);
get_abs_path(&file, file_tmp);
if (!check_file_access(file, sock)) return 0;
@@ -1405,7 +1265,7 @@ static int handle_request_forget(listen_socket_t *sock, /* {{{ */
assert(1==0);
} /* }}} static int handle_request_forget */
-static int handle_request_queue (listen_socket_t *sock) /* {{{ */
+static int handle_request_queue (HANDLER_PROTO) /* {{{ */
{
cache_item_t *ci;
@@ -1423,9 +1283,7 @@ static int handle_request_queue (listen_socket_t *sock) /* {{{ */
return send_response(sock, RESP_OK, "in queue.\n");
} /* }}} int handle_request_queue */
-static int handle_request_update (listen_socket_t *sock, /* {{{ */
- time_t now,
- char *buffer, size_t buffer_size)
+static int handle_request_update (HANDLER_PROTO) /* {{{ */
{
char *file, file_tmp[PATH_MAX];
int values_num = 0;
@@ -1434,17 +1292,12 @@ static int handle_request_update (listen_socket_t *sock, /* {{{ */
cache_item_t *ci;
- status = has_privilege(sock, PRIV_HIGH);
- if (status <= 0)
- return status;
-
/* save it for the journal later */
strncpy(orig_buf, buffer, sizeof(orig_buf)-1);
status = buffer_get_field (&buffer, &buffer_size, &file);
if (status != 0)
- return send_response(sock, RESP_ERR,
- "Usage: UPDATE <filename> <values> [<values> ...]\n");
+ return syntax_error(sock,cmd);
pthread_mutex_lock(&stats_lock);
stats_updates_received++;
@@ -1590,7 +1443,7 @@ static int handle_request_update (listen_socket_t *sock, /* {{{ */
/* we came across a "WROTE" entry during journal replay.
* throw away any values that we have accumulated for this file
*/
-static int handle_request_wrote (const char *buffer, time_t now) /* {{{ */
+static int handle_request_wrote (HANDLER_PROTO) /* {{{ */
{
int i;
cache_item_t *ci;
@@ -1621,7 +1474,7 @@ static int handle_request_wrote (const char *buffer, time_t now) /* {{{ */
} /* }}} int handle_request_wrote */
/* start "BATCH" processing */
-static int batch_start (listen_socket_t *sock) /* {{{ */
+static int batch_start (HANDLER_PROTO) /* {{{ */
{
int status;
if (sock->batch_start)
@@ -1636,7 +1489,7 @@ static int batch_start (listen_socket_t *sock) /* {{{ */
} /* }}} static int batch_start */
/* finish "BATCH" processing and return results to the client */
-static int batch_done (listen_socket_t *sock) /* {{{ */
+static int batch_done (HANDLER_PROTO) /* {{{ */
{
assert(sock->batch_start);
sock->batch_start = 0;
@@ -1644,20 +1497,231 @@ static int batch_done (listen_socket_t *sock) /* {{{ */
return send_response(sock, RESP_OK, "errors\n");
} /* }}} static int batch_done */
+static int handle_request_quit (HANDLER_PROTO) /* {{{ */
+{
+ return -1;
+} /* }}} static int handle_request_quit */
+
+struct command COMMANDS[] = {
+ {
+ "UPDATE",
+ handle_request_update,
+ PRIV_HIGH,
+ CMD_CONTEXT_ANY,
+ "UPDATE <filename> <values> [<values> ...]\n"
+ ,
+ "Adds the given file to the internal cache if it is not yet known and\n"
+ "appends the given value(s) to the entry. See the rrdcached(1) manpage\n"
+ "for details.\n"
+ "\n"
+ "Each <values> has the following form:\n"
+ " <values> = <time>:<value>[:<value>[...]]\n"
+ "See the rrdupdate(1) manpage for details.\n"
+ },
+ {
+ "WROTE",
+ handle_request_wrote,
+ PRIV_HIGH,
+ CMD_CONTEXT_JOURNAL,
+ NULL,
+ NULL
+ },
+ {
+ "FLUSH",
+ handle_request_flush,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT | CMD_CONTEXT_BATCH,
+ "FLUSH <filename>\n"
+ ,
+ "Adds the given filename to the head of the update queue and returns\n"
+ "after it has been dequeued.\n"
+ },
+ {
+ "FLUSHALL",
+ handle_request_flushall,
+ PRIV_HIGH,
+ CMD_CONTEXT_CLIENT,
+ "FLUSHALL\n"
+ ,
+ "Triggers writing of all pending updates. Returns immediately.\n"
+ },
+ {
+ "PENDING",
+ handle_request_pending,
+ PRIV_HIGH,
+ CMD_CONTEXT_CLIENT,
+ "PENDING <filename>\n"
+ ,
+ "Shows any 'pending' updates for a file, in order.\n"
+ "The updates shown have not yet been written to the underlying RRD file.\n"
+ },
+ {
+ "FORGET",
+ handle_request_forget,
+ PRIV_HIGH,
+ CMD_CONTEXT_ANY,
+ "FORGET <filename>\n"
+ ,
+ "Removes the file completely from the cache.\n"
+ "Any pending updates for the file will be lost.\n"
+ },
+ {
+ "QUEUE",
+ handle_request_queue,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT,
+ "QUEUE\n"
+ ,
+ "Shows all files in the output queue.\n"
+ "The output is zero or more lines in the following format:\n"
+ "(where <num_vals> is the number of values to be written)\n"
+ "\n"
+ "<num_vals> <filename>\n"
+ },
+ {
+ "STATS",
+ handle_request_stats,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT,
+ "STATS\n"
+ ,
+ "Returns some performance counters, see the rrdcached(1) manpage for\n"
+ "a description of the values.\n"
+ },
+ {
+ "HELP",
+ handle_request_help,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT,
+ "HELP [<command>]\n",
+ NULL, /* special! */
+ },
+ {
+ "BATCH",
+ batch_start,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT,
+ "BATCH\n"
+ ,
+ "The 'BATCH' command permits the client to initiate a bulk load\n"
+ " of commands to rrdcached.\n"
+ "\n"
+ "Usage:\n"
+ "\n"
+ " client: BATCH\n"
+ " server: 0 Go ahead. End with dot '.' on its own line.\n"
+ " client: command #1\n"
+ " client: command #2\n"
+ " client: ... and so on\n"
+ " client: .\n"
+ " server: 2 errors\n"
+ " server: 7 message for command #7\n"
+ " server: 9 message for command #9\n"
+ "\n"
+ "For more information, consult the rrdcached(1) documentation.\n"
+ },
+ {
+ ".", /* BATCH terminator */
+ batch_done,
+ PRIV_LOW,
+ CMD_CONTEXT_BATCH,
+ NULL,
+ NULL
+ },
+ {
+ "QUIT",
+ handle_request_quit,
+ PRIV_LOW,
+ CMD_CONTEXT_CLIENT | CMD_CONTEXT_BATCH,
+ "QUIT\n"
+ ,
+ "Disconnect from rrdcached.\n"
+ },
+ {NULL,NULL,0,0,NULL,NULL} /* LAST ENTRY */
+};
+
+static struct command *find_command(char *cmd)
+{
+ struct command *c = COMMANDS;
+
+ while (c->cmd != NULL)
+ {
+ if (strcasecmp(cmd, c->cmd) == 0)
+ break;
+ c++;
+ }
+
+ if (c->cmd == NULL)
+ return NULL;
+ else
+ return c;
+}
+
+/* check whether commands are received in the expected context */
+static int command_check_context(listen_socket_t *sock, struct command *cmd)
+{
+ if (sock == NULL)
+ return (cmd->context & CMD_CONTEXT_JOURNAL);
+ else if (sock->batch_start)
+ return (cmd->context & CMD_CONTEXT_BATCH);
+ else
+ return (cmd->context & CMD_CONTEXT_CLIENT);
+
+ /* NOTREACHED */
+ assert(1==0);
+}
+
+static int handle_request_help (HANDLER_PROTO) /* {{{ */
+{
+ int status;
+ char *cmd_str;
+ char *resp_txt;
+ struct command *help = NULL;
+
+ status = buffer_get_field (&buffer, &buffer_size, &cmd_str);
+ if (status == 0)
+ help = find_command(cmd_str);
+
+ if (help && (help->syntax || help->help))
+ {
+ char tmp[CMD_MAX];
+
+ snprintf(tmp, sizeof(tmp)-1, "Help for %s\n", help->cmd);
+ resp_txt = tmp;
+
+ if (help->syntax)
+ add_response_info(sock, "Usage: %s\n", help->syntax);
+
+ if (help->help)
+ add_response_info(sock, "%s\n", help->help);
+ }
+ else
+ {
+ help = COMMANDS;
+ resp_txt = "Command overview\n";
+
+ while (help->cmd)
+ {
+ if (help->syntax)
+ add_response_info(sock, "%s", help->syntax);
+ help++;
+ }
+ }
+
+ return send_response(sock, RESP_OK, resp_txt);
+} /* }}} int handle_request_help */
+
/* if sock==NULL, we are in journal replay mode */
-static int handle_request (listen_socket_t *sock, /* {{{ */
- time_t now,
- char *buffer, size_t buffer_size)
+static int handle_request (DISPATCH_PROTO) /* {{{ */
{
- char *buffer_ptr;
- char *command;
+ char *buffer_ptr = buffer;
+ char *cmd_str = NULL;
+ struct command *cmd = NULL;
int status;
assert (buffer[buffer_size - 1] == '\0');
- buffer_ptr = buffer;
- command = NULL;
- status = buffer_get_field (&buffer_ptr, &buffer_size, &command);
+ status = buffer_get_field (&buffer_ptr, &buffer_size, &cmd_str);
if (status != 0)
{
RRDD_LOG (LOG_INFO, "handle_request: Unable parse command.");
@@ -1667,38 +1731,18 @@ static int handle_request (listen_socket_t *sock, /* {{{ */
if (sock != NULL && sock->batch_start)
sock->batch_cmd++;
- if (strcasecmp (command, "update") == 0)
- return (handle_request_update (sock, now, buffer_ptr, buffer_size));
- else if (strcasecmp (command, "wrote") == 0 && sock == NULL)
- {
- /* this is only valid in replay mode */
- return (handle_request_wrote (buffer_ptr, now));
- }
- else if (strcasecmp (command, "flush") == 0)
- return (handle_request_flush (sock, buffer_ptr, buffer_size));
- else if (strcasecmp (command, "flushall") == 0)
- return (handle_request_flushall(sock));
- else if (strcasecmp (command, "pending") == 0)
- return (handle_request_pending(sock, buffer_ptr, buffer_size));
- else if (strcasecmp (command, "forget") == 0)
- return (handle_request_forget(sock, buffer_ptr, buffer_size));
- else if (strcasecmp (command, "queue") == 0)
- return (handle_request_queue(sock));
- else if (strcasecmp (command, "stats") == 0)
- return (handle_request_stats (sock));
- else if (strcasecmp (command, "help") == 0)
- return (handle_request_help (sock, buffer_ptr, buffer_size));
- else if (strcasecmp (command, "batch") == 0 && sock != NULL)
- return batch_start(sock);
- else if (strcasecmp (command, ".") == 0 && sock != NULL && sock->batch_start)
- return batch_done(sock);
- else if (strcasecmp (command, "quit") == 0)
- return -1;
- else
- return send_response(sock, RESP_ERR, "Unknown command: %s\n", command);
+ cmd = find_command(cmd_str);
+ if (!cmd)
+ return send_response(sock, RESP_ERR, "Unknown command: %s\n", cmd_str);
- /* NOTREACHED */
- assert(1==0);
+ status = has_privilege(sock, cmd->min_priv);
+ if (status <= 0)
+ return status;
+
+ if (!command_check_context(sock, cmd))
+ return send_response(sock, RESP_ERR, "Can't use '%s' here.\n", cmd_str);
+
+ return cmd->handler(cmd, sock, now, buffer_ptr, buffer_size);
} /* }}} int handle_request */
/* MUST NOT hold journal_lock before calling this */
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