MEDIUM: log: add the ability to include samples in logs
Using %[expression] it becomes possible to make the log engine fetch
some samples from the request or the response and provide them in the
logs. Note that this feature is still limited, it does not yet allow
to apply converters, to limit the output length, nor to specify the
direction which should be fetched when a fetch function works in both
directions.
However it's quite convenient to log SSL information or to include some
information that are used in stick tables.
It is worth noting that this has been done in the generic log format
handler, which means that the same information may be used to build the
unique-id header and to pass the information to a backend server.
diff --git a/src/log.c b/src/log.c
index a1bc78f..ae7d122 100644
--- a/src/log.c
+++ b/src/log.c
@@ -33,6 +33,7 @@
#include <proto/frontend.h>
#include <proto/log.h>
+#include <proto/sample.h>
#include <proto/stream_interface.h>
#ifdef USE_OPENSSL
#include <proto/ssl_sock.h>
@@ -304,6 +305,51 @@
}
/*
+ * Parse the sample fetch expression <text> and add a node to <list_format> upon
+ * success. At the moment, sample converters are not yet supported but fetch arguments
+ * should work.
+ */
+void add_sample_to_logformat_list(char *text, char *arg, int arg_len, struct proxy *curpx, struct list *list_format, int options)
+{
+ char *cmd[2];
+ struct sample_expr *expr;
+ struct logformat_node *node;
+ int cmd_arg;
+
+ cmd[0] = text;
+ cmd[1] = "";
+ cmd_arg = 0;
+
+ expr = sample_parse_expr(cmd, &cmd_arg, trash.str, trash.size);
+ if (!expr) {
+ Warning("log-format: sample fetch <%s> failed with : %s\n", text, trash.str);
+ return;
+ }
+
+ node = calloc(1, sizeof(struct logformat_node));
+ node->type = LOG_FMT_EXPR;
+ node->expr = expr;
+ node->options = options;
+
+ if (arg_len) {
+ node->arg = my_strndup(arg, arg_len);
+ parse_logformat_var_args(node->arg, node);
+ }
+ if (expr->fetch->cap & SMP_CAP_REQ)
+ node->options |= LOG_OPT_REQ_CAP; /* fetch method is request-compatible */
+
+ if (expr->fetch->cap & SMP_CAP_RES)
+ node->options |= LOG_OPT_RES_CAP; /* fetch method is response-compatible */
+
+ /* check if we need to allocate an hdr_idx struct for HTTP parsing */
+ /* Note, we may also need to set curpx->to_log with certain fetches */
+ if (expr->fetch->cap & SMP_CAP_L7)
+ curpx->acl_requires |= ACL_USE_L7_ANY;
+
+ LIST_ADDQ(list_format, &node->list);
+}
+
+/*
* Parse the log_format string and fill a linked list.
* Variable name are preceded by % and composed by characters [a-zA-Z0-9]* : %varname
* You can set arguments using { } : %{many arguments}varname
@@ -346,12 +392,16 @@
*/
switch (pformat) {
case LF_STARTVAR: // text immediately following a '%'
- arg = NULL;
+ arg = NULL; var = NULL;
arg_len = var_len = 0;
if (*str == '{') { // optional argument
cformat = LF_STARG;
arg = str + 1;
}
+ else if (*str == '[') {
+ cformat = LF_STEXPR;
+ var = str + 1; // store expr in variable name
+ }
else if (isalnum((int)*str)) { // variable name
cformat = LF_VAR;
var = str;
@@ -371,23 +421,35 @@
break;
case LF_EDARG: // text immediately following '%{arg}'
- if (isalnum((int)*str)) { // variable name
+ if (*str == '[') {
+ cformat = LF_STEXPR;
+ var = str + 1; // store expr in variable name
+ break;
+ }
+ else if (isalnum((int)*str)) { // variable name
cformat = LF_VAR;
var = str;
break;
}
-
Warning("Skipping isolated argument in log-format line : '%%{%s}'\n", arg);
cformat = LF_INIT;
break;
+ case LF_STEXPR: // text immediately following '%['
+ if (*str == ']') { // end of arg
+ cformat = LF_EDEXPR;
+ var_len = str - var;
+ *str = 0; // needed for parsing the expression
+ }
+ break;
+
case LF_VAR: // text part of a variable name
var_len = str - var;
if (!isalnum((int)*str))
cformat = LF_INIT; // not variable name anymore
break;
- default: // LF_INIT, LF_TEXT, LF_SEPARATOR, LF_END
+ default: // LF_INIT, LF_TEXT, LF_SEPARATOR, LF_END, LF_EDEXPR
cformat = LF_INIT;
}
@@ -405,6 +467,9 @@
case LF_VAR:
parse_logformat_var(arg, arg_len, var, var_len, curproxy, list_format, &options);
break;
+ case LF_STEXPR:
+ add_sample_to_logformat_list(var, arg, arg_len, curproxy, list_format, options);
+ break;
case LF_TEXT:
case LF_SEPARATOR:
add_to_logformat_list(sp, str, pformat, list_format);
@@ -414,8 +479,8 @@
}
}
- if (pformat == LF_STARTVAR || pformat == LF_STARG)
- Warning("Ignoring end of truncated log-format line after '%s'\n", arg ? arg : "%");
+ if (pformat == LF_STARTVAR || pformat == LF_STARG || pformat == LF_STEXPR)
+ Warning("Ignoring end of truncated log-format line after '%s'\n", var ? var : arg ? arg : "%");
}
/*
@@ -823,8 +888,9 @@
list_for_each_entry(tmp, list_format, list) {
const char *src = NULL;
- switch (tmp->type) {
+ struct sample *key;
+ switch (tmp->type) {
case LOG_FMT_SEPARATOR:
if (!last_isspace) {
LOGCHAR(' ');
@@ -841,6 +907,21 @@
last_isspace = 0;
break;
+ case LOG_FMT_EXPR: // sample expression, may be request or response
+ key = NULL;
+ if (tmp->options & LOG_OPT_REQ_CAP)
+ key = sample_fetch_string(be, s, txn, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, tmp->expr);
+ if (!key && (tmp->options & LOG_OPT_RES_CAP))
+ key = sample_fetch_string(be, s, txn, SMP_OPT_DIR_RES|SMP_OPT_FINAL, tmp->expr);
+ if (!key)
+ break;
+ ret = lf_text_len(tmplog, key->data.str.str, key->data.str.len, dst + maxsize - tmplog, tmp);
+ if (ret == 0)
+ goto out;
+ tmplog = ret;
+ last_isspace = 0;
+ break;
+
case LOG_FMT_CLIENTIP: // %ci
ret = lf_ip(tmplog, (struct sockaddr *)&s->req->prod->conn->addr.from,
dst + maxsize - tmplog, tmp);