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Improve parsing of the response to sentinel masters requests
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Redis 3.2 has additional lines in the response.
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@TysonAndre-tmg
TysonAndre-tmg committed Jun 21, 2017
1 parent 9de9e99 commit 9820caa
Showing 1 changed file with 212 additions and 87 deletions.
299 changes: 212 additions & 87 deletions src/nc_sentinel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -112,132 +112,257 @@ sentinel_close(struct context *ctx, struct conn *conn)
server_close(ctx, conn);
}

/* Returns true if the expected prefix and sep byte was parsed from line_buf into tmp_string */
static bool
parse_expected_key_from_mbuf(struct mbuf *line_buf, const char sep, const struct string *expected_prefix, struct string *tmp_string)
{
// tmp_string is already initialized. It will be modified by this function.
// If the result is NC_OK, it will have the same contents as expected_prefix
rstatus_t status;
status = mbuf_read_string(line_buf, '=', tmp_string);
if (status != NC_OK) {
log_error("skip server %s%c prefix failed.", expected_prefix->data, sep);
return false;
}
if (!string_has_prefix(tmp_string, expected_prefix)) {
log_error("Expected %s%c", expected_prefix->data, sep);
return false;
}
return true;
}

static rstatus_t
sentinel_proc_sentinel_info(struct context *ctx, struct server *sentinel, struct msg *msg)
{
rstatus_t status;
int i, master_num, switch_num, server_port;
struct string server_name, server_ip, sentinel_masters_prefix, tmp_string;
struct string server_name;
struct string server_ip;
struct string const_sentinel_masters_prefix;
struct string const_sentinel_key_prefix;
struct string const_master_prefix;
struct string const_server_key;
struct string const_name_key;
struct string const_address_key;
struct string const_status_key;

struct string tmp_string;
struct string tmp_value;
struct server *server;
struct mbuf *line_buf;
int lines_with_master_count = 0;

string_init(&tmp_string);
string_init(&tmp_value);
string_init(&server_name);
string_init(&server_ip);
string_set_text(&sentinel_masters_prefix, "sentinel_masters");

string_set_text(&const_sentinel_masters_prefix, "sentinel_masters");
string_set_text(&const_sentinel_key_prefix, "sentinel_");
string_set_text(&const_master_prefix, "master");
string_set_text(&const_name_key, "name");
string_set_text(&const_address_key, "address");
string_set_text(&const_status_key, "status");

/*
* Example output to parse (number of lines with "sentinel_" vary with the version. All lines end in \r\n)
*
* $946
* # Sentinel
* sentinel_masters:10
* sentinel_tilt:0
* sentinel_running_scripts:0
* sentinel_scripts_queue_length:0
* sentinel_simulate_failure_flags:0
* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3
* master1:name=my_db004,status=ok,address=10.155.155.5:6383,slaves=1,sentinels=3
* master2:name=my_db005,status=ok,address=10.155.155.5:6384,slaves=1,sentinels=3
* master3:name=my_db003,status=ok,address=10.155.155.6:6382,slaves=1,sentinels=3
* master4:name=my_db002,status=ok,address=10.155.155.5:6381,slaves=1,sentinels=3
* master5:name=my_db006,status=ok,address=10.155.155.5:6385,slaves=1,sentinels=3
* master6:name=my_db009,status=ok,address=10.155.155.5:6388,slaves=1,sentinels=3
* master7:name=my_db000,status=ok,address=10.155.155.5:6379,slaves=1,sentinels=3
* master8:name=my_db008,status=ok,address=10.155.155.5:6387,slaves=1,sentinels=3
* master9:name=my_db007,status=ok,address=10.155.155.5:6386,slaves=1,sentinels=3
*/
line_buf = mbuf_get();
if (line_buf == NULL) {
goto error;
}

/* get sentinel master num at line 3 */
msg_read_line(msg, line_buf, 3);
if (mbuf_length(line_buf) == 0) {
log_error("read line failed from sentinel ack info when skip line not used.");
goto error;
}
status = mbuf_read_string(line_buf, ':', &tmp_string);
if (status != NC_OK || string_compare(&sentinel_masters_prefix, &tmp_string)) {
goto error;
}
status = mbuf_read_string(line_buf, CR, &tmp_string);
if (status != NC_OK) {
goto error;
}
master_num = nc_atoi(tmp_string.data, tmp_string.len);
if (master_num < 0) {
log_error("parse master number from sentinel ack info failed.");
goto error;
}

/* skip 3 line in ack info which is not used. */
msg_read_line(msg, line_buf, 3);
/* Assume the first two lines are "$[len]" and "# Sentinel" */
msg_read_line(msg, line_buf, 2);
if (mbuf_length(line_buf) == 0) {
log_error("read line failed from sentinel ack info when skip line not used.");
log_error("read first two lines failed from sentinel ack info when skip line not used.");
goto error;
}

/* parse master info from sentinel ack info */
switch_num = 0;
for (i = 0; i < master_num; i++) {
while (1) {
/* read a single line, starting from line 3 */
msg_read_line(msg, line_buf, 1);
if (mbuf_length(line_buf) == 0) {
log_error("read line failed from sentinel ack info when parse master item.");
goto error;
}

/* skip master item server name prefix */
status = mbuf_read_string(line_buf, '=', NULL);
if (status != NC_OK) {
log_error("skip server name prefix failed.");
if (master_num == 0 && lines_with_master_count == 1) {
break;
}
log_error("read third lines failed from sentinel ack info when skip line not used.");
goto error;
}

/* get server name */
status = mbuf_read_string(line_buf, ',', &server_name);
/* First, verify the line is of the form "key:value" */
status = mbuf_read_string(line_buf, ':', &tmp_string);
/* TODO: handle 0 masters? */
if (status != NC_OK) {
log_error("get server name failed.");
goto error;
}

server = server_find_by_name(ctx, sentinel->owner, &server_name);
if (server == NULL) {
log_error("unknown server name:%.*s", server_name.len, server_name.data);
goto error;
}

/* skip master status */
status = mbuf_read_string(line_buf, ',', NULL);
if (status != NC_OK) {
log_error("get master status failed.");
goto error;
if (string_has_prefix(&tmp_string, &const_master_prefix)) {
if (lines_with_master_count != 1) {
log_error("Saw a key for a master before seeing a line with sentinel_masters");
goto error;
}
if (master_num == 0) {
log_error("Saw info for a master, but also saw sentinel_masters:0");
goto error;
}

/* parse master info from sentinel ack info */
/* E.g. "master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
switch_num = 0;
for (i = 0; i < master_num; i++) {
/* For the first line, we read everything up to the ':' already */
if (i > 0) {
msg_read_line(msg, line_buf, 1);
if (mbuf_length(line_buf) == 0) {
log_error("read line failed from sentinel ack info when parse master item.");
goto error;
}

/* skip master item server name prefix */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^^^^ */
status = mbuf_read_string(line_buf, ':', NULL);
if (status != NC_OK) {
log_error("skip server name prefix failed.");
goto error;
}
}

/* skip master item server name prefix */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^ */
if (!parse_expected_key_from_mbuf(line_buf, '=', &const_name_key, &tmp_string)) {
goto error;
}

/* get server name */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^ */
status = mbuf_read_string(line_buf, ',', &server_name);
if (status != NC_OK) {
log_error("get server name failed.");
goto error;
}

server = server_find_by_name(ctx, sentinel->owner, &server_name);
if (server == NULL) {
log_error("unknown server name:%.*s", server_name.len, server_name.data);
goto error;
}

/* skip master status */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^^^ */
if (!parse_expected_key_from_mbuf(line_buf, '=', &const_status_key, &tmp_string)) {
goto error;
}
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^ */
status = mbuf_read_string(line_buf, ',', NULL);
if (status != NC_OK) {
log_error("get master status failed.");
goto error;
}

/* skip ip string prefix name */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^^^^ */
if (!parse_expected_key_from_mbuf(line_buf, '=', &const_address_key, &tmp_string)) {
goto error;
}

/* get server ip string */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^^^^^^^^^ */
status = mbuf_read_string(line_buf, ':', &server_ip);
if (status != NC_OK) {
log_error("get server ip string failed.");
goto error;
}

/* get server port */
/* master0:name=my_db001,status=ok,address=10.155.155.5:6380,slaves=1,sentinels=3" */
/* ^^^^ */
status = mbuf_read_string(line_buf, ',', &tmp_string);
if (status != NC_OK) {
log_error("get server port string failed.");
goto error;
}
server_port = nc_atoi(tmp_string.data, tmp_string.len);
if (server_port < 0) {
log_error("translate server port string to int failed.");
goto error;
}
/* Ignore the ,slaves=%d,sentinels=%d field of INFO */

status = server_switch(ctx, server, &server_ip, server_port);
/* if server is switched, add switch number */
if (status == NC_OK) {
switch_num++;
}
}

if (switch_num > 0) {
conf_rewrite(ctx);
}

status = NC_OK;
goto done;
}

/* skip ip string prefix name */
status = mbuf_read_string(line_buf, '=', NULL);
// Parse everything after the ':' to the first '\r' (The value of the key-value pair)
status = mbuf_read_string(line_buf, CR, &tmp_value);
if (status != NC_OK) {
log_error("skip master item address prefix failed.");
goto error;
}

/* get server ip string */
status = mbuf_read_string(line_buf, ':', &server_ip);
if (status != NC_OK) {
log_error("get server ip string failed.");
goto error;
}

/* get server port */
status = mbuf_read_string(line_buf, ',', &tmp_string);
if (status != NC_OK) {
log_error("get server port string failed.");
goto error;
}
server_port = nc_atoi(tmp_string.data, tmp_string.len);
if (server_port < 0) {
log_error("tanslate server port string to int failed.");
goto error;
}

status = server_switch(ctx, server, &server_ip, server_port);
/* if server is switched, add switch number */
if (status == NC_OK) {
switch_num++;
if (!string_has_prefix(&tmp_string, &const_sentinel_key_prefix)) {
/* check against "master" */
log_warn("Found line in \"sentinel info\" output not beginning with \"sentinel_\" or \"master\", skipping");
continue;
} else {
if (string_has_prefix(&tmp_string, &const_sentinel_masters_prefix)) {
if (lines_with_master_count != 0) {
log_error("Found multiple \"sentinel_masters:\" lines");
goto error;
}
lines_with_master_count++;

// Read the number from tmp_value, from a line such as "sentinel_masters:10"
master_num = nc_atoi(tmp_value.data, tmp_value.len);
if (master_num < 0) {
log_error("parse master number from sentinel ack info failed.");
goto error;
}
}
}
}

if (switch_num > 0) {
conf_rewrite(ctx);
if (lines_with_master_count == 0) {
log_error("Did not find line in \"sentinel info\" output with key \"sentinel_masters\"");
goto error;
}

status = NC_OK;
goto done;

done:
if (line_buf != NULL) {
mbuf_put(line_buf);
}
string_deinit(&tmp_string);
string_deinit(&tmp_value);
string_deinit(&server_name);
string_deinit(&server_ip);
return status;
Expand Down Expand Up @@ -452,7 +577,7 @@ sentinel_recv_done(struct context *ctx, struct conn *conn, struct msg *msg,
}

rsp_put(msg);

if (status != NC_OK) {
log_error("sentinel's response error, close sentinel conn.");
conn->done = 1;
Expand Down

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