From: Amit Gupta Date: Fri, 1 May 2009 12:38:50 +0000 (+0200) Subject: apache plugin: Use the HTTP header to determine the server software. X-Git-Tag: collectd-4.7.0~38^2~2 X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=b046582ac6fd2392a8971c95d71d85ee229277e0;p=collectd.git apache plugin: Use the HTTP header to determine the server software. On Wed, Apr 22, 2009 at 1:53 PM, Florian Forster wrote: > I think we have two options left: > > - Set a header callback using the CURLOPT_HEADERFUNCTION option and > look for the <91>Server<92> header field. If it contains <93>lighttpd<94>, assume > lighttpd, Apache otherwise. > > - Let the user configure which server software he's using. > > The two could be combined, of course: Use the user's setting if he has > given one, (try to) determine the server software automatically if not. > > What do you think? yeah this sounds good. While I thought about parsing the headers initially but then the server headers can easily be changed, so I wasn't sure about this approach earlier. Combing this with the user specified server configuration value seems like the best solution. Do find the patch attached. I am using st->server_type variable which will be set to APACHE or LIGHTTPD based on the following logic: - If the user has specified Server element in the conf file and it is "apache" or "lighttpd", then set st->server_type variable appropriately, otherwise ignore the Server value - Parse the headers (only if the Server element is NULL or invalid) to determine the type and set the st->server_type variable accordingly - if st->server_type is not set as yet, then default it to apache Regards Amit Signed-off-by: Florian Forster --- diff --git a/src/apache.c b/src/apache.c index c11f55d8..69633d6f 100644 --- a/src/apache.c +++ b/src/apache.c @@ -31,14 +31,16 @@ #include -enum server_type +enum server_enum { APACHE = 0, LIGHTTPD }; + struct apache_s { + int server_type; char *name; char *host; char *url; @@ -47,6 +49,7 @@ struct apache_s int verify_peer; int verify_host; char *cacert; + char *server; // user specific server type char *apache_buffer; char apache_curl_error[CURL_ERROR_SIZE]; size_t apache_buffer_size; @@ -70,6 +73,7 @@ static void apache_free (apache_t *st) sfree (st->user); sfree (st->pass); sfree (st->cacert); + sfree (st->server); sfree (st->apache_buffer); if (st->curl) { curl_easy_cleanup(st->curl); @@ -116,6 +120,32 @@ static size_t apache_curl_callback (void *buf, size_t size, size_t nmemb, return (len); } /* int apache_curl_callback */ +static size_t apache_header_callback (void *buf, size_t size, size_t nmemb, + void *user_data) +{ + size_t len = size * nmemb; + apache_t *st; + + st = user_data; + if (st == NULL) + { + ERROR ("apache plugin: apache_header_callback: " + "user_data pointer is NULL."); + return (0); + } + + if (len <= 0) + return len; + + // look for the Server header + if ((strstr(buf, "Server: ") != NULL) && + (strstr(buf, "lighttpd") != NULL)) { + st->server_type = LIGHTTPD; + } + + return len; +} /* apache_header_callback */ + /* Configuration handling functiions * * @@ -241,6 +271,8 @@ static int config_add (oconfig_item_t *ci) status = config_set_boolean (&st->verify_host, child); else if (strcasecmp ("CACert", child->key) == 0) status = config_set_string (&st->cacert, child); + else if (strcasecmp ("Server", child->key) == 0) + status = config_set_string (&st->server, child); else { WARNING ("apache plugin: Option `%s' not allowed here.", @@ -370,6 +402,26 @@ static int init_host (apache_t *st) /* {{{ */ curl_easy_setopt (st->curl, CURLOPT_WRITEFUNCTION, apache_curl_callback); curl_easy_setopt (st->curl, CURLOPT_WRITEDATA, st); + + st->server_type = -1; // not set as yet + // if the user specified string doesn't match apache or lighttpd, then + // ignore it. Headers will be parsed to find out the server type + if (st->server != NULL) + { + if (strcasecmp(st->server, "apache") == 0) + st->server_type = APACHE; + else if (strcasecmp(st->server, "lighttpd") == 0) + st->server_type = LIGHTTPD; + } + + // if not found register a header callback to determine the + // server_type + if (st->server_type == -1) + { + curl_easy_setopt (st->curl, CURLOPT_HEADERFUNCTION, apache_header_callback); + curl_easy_setopt (st->curl, CURLOPT_WRITEHEADER, st); + } + curl_easy_setopt (st->curl, CURLOPT_USERAGENT, PACKAGE_NAME"/"PACKAGE_VERSION); curl_easy_setopt (st->curl, CURLOPT_ERRORBUFFER, st->apache_curl_error); @@ -460,7 +512,7 @@ static void submit_gauge (const char *type, const char *type_instance, submit_value (type, type_instance, v, st); } /* void submit_gauge */ -static void submit_scoreboard (char *buf, int server, apache_t *st) +static void submit_scoreboard (char *buf, apache_t *st) { /* * Scoreboard Key: @@ -496,7 +548,6 @@ static void submit_scoreboard (char *buf, int server, apache_t *st) long long response_end = 0LL; int i; - for (i = 0; buf[i] != '\0'; i++) { if (buf[i] == '.') open++; @@ -519,7 +570,7 @@ static void submit_scoreboard (char *buf, int server, apache_t *st) else if (buf[i] == 'S') response_end++; } - if (server == APACHE) + if (st->server_type == APACHE) { submit_gauge ("apache_scoreboard", "open" , open, st); submit_gauge ("apache_scoreboard", "waiting" , waiting, st); @@ -545,7 +596,6 @@ static void submit_scoreboard (char *buf, int server, apache_t *st) submit_gauge ("apache_scoreboard", "request_end" , request_end, st); submit_gauge ("apache_scoreboard", "response_start", response_start, st); submit_gauge ("apache_scoreboard", "response_end" , response_end, st); - } } @@ -560,7 +610,6 @@ static int apache_read_host (user_data_t *user_data) /* {{{ */ char *fields[4]; int fields_num; - int server = LIGHTTPD; /* default is lighttpd */ apache_t *st; @@ -587,6 +636,10 @@ static int apache_read_host (user_data_t *user_data) /* {{{ */ return (-1); } + // fallback - server_type to apache if not set at this time + if (st->server_type == -1) + st->server_type = APACHE; + ptr = st->apache_buffer; saveptr = NULL; while ((lines[lines_num] = strtok_r (ptr, "\n\r", &saveptr)) != NULL) @@ -615,17 +668,8 @@ static int apache_read_host (user_data_t *user_data) /* {{{ */ } else if (fields_num == 2) { - /* find out if the server is apache from the mod_status - * output. apache mod_status output has additional - * fields which lighttpd mod_status output doesn't have - * e.g: ReqPerSec. submit_scoreboard needs server type - * information and thus it is important to pick up a - * field before scoreboard gets parsed to set the - * server type */ - if (strcmp (fields[0], "ReqPerSec:") == 0) - server = APACHE; - else if (strcmp (fields[0], "Scoreboard:") == 0) - submit_scoreboard (fields[1], server, st); + if (strcmp (fields[0], "Scoreboard:") == 0) + submit_scoreboard (fields[1], st); else if (strcmp (fields[0], "BusyServers:") == 0) submit_gauge ("apache_connections", NULL, atol (fields[1]), st); }