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MINOR: debug: support logging to various sinks

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As discussed in the thread below [1], the debug converter is currently
not of much use given that it's only built when DEBUG_EXPR is set, and
it is limited to stderr only.

This patch changes this to make it take an optional prefix and an optional
target sink so that it can log to stdout, stderr or a ring buffer. The
default output is the "buf0" ring buffer, that can be consulted from the
CLI.

[1] https://www.mail-archive.com/haproxy@formilux.org/msg35671.html

Note: if this patch is backported, it also requires the following commit to
work: 46dfd78cbf ("BUG/MINOR: sample: always check converters' arguments").
This commit is contained in:
Willy Tarreau 2019-12-17 10:07:25 +01:00
parent ba22e901b3
commit 0851fd5eef
2 changed files with 84 additions and 36 deletions
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18
doc/configuration.txt
View File

@ -13284,10 +13284,20 @@ da-csv-conv(<prop>[,<prop>*])
default_backend servers
http-request set-header X-DeviceAtlas-Data %[req.fhdr(User-Agent),da-csv(primaryHardwareType,osName,osVersion,browserName,browserVersion,browserRenderingEngine)]
debug
This converter is used as debug tool. It dumps on screen the content and the
type of the input sample. The sample is returned as is on its output. This
converter only exists when haproxy was built with debugging enabled.
debug([<prefix][,<destination>])
This converter is used as debug tool. It takes a capture of the input sample
and sends it to event sink <destination>, which may designate a ring buffer
such as "buf0", as well as "stdout", or "stderr". Available sinks may be
checked at run time by issuing "show events" on the CLI. When not specified,
the output will be "buf0", which may be consulted via the CLI's "show events"
command. An optional prefix <prefix> may be passed to help distinguish
outputs from multiple expressions. It will then appear before the colon in
the output message. The input sample is passed as-is on the output, so that
it is safe to insert the debug converter anywhere in a chain, even with non-
printable sample types.
Example:
tcp-request connection track-sc0 src,debug(track-sc)
div(<value>)
Divides the input value of type signed integer by <value>, and returns the

102
src/sample.c
View File

@ -32,6 +32,7 @@
#include <proto/proxy.h>
#include <proto/protocol_buffers.h>
#include <proto/sample.h>
#include <proto/sink.h>
#include <proto/stick_table.h>
#include <proto/vars.h>
@ -1436,45 +1437,85 @@ void release_sample_expr(struct sample_expr *expr)
/* These functions set the data type on return. */
/*****************************************************************/
#ifdef DEBUG_EXPR
static int sample_conv_debug(const struct arg *arg_p, struct sample *smp, void *private)
{
int i;
struct sample tmp;
struct buffer *buf;
struct sink *sink;
struct ist line;
char *pfx;
if (!(global.mode & MODE_QUIET) || (global.mode & (MODE_VERBOSE | MODE_STARTING))) {
fprintf(stderr, "[debug converter] type: %s ", smp_to_type[smp->data.type]);
if (!sample_casts[smp->data.type][SMP_T_STR]) {
fprintf(stderr, "(undisplayable)");
} else {
buf = alloc_trash_chunk();
if (!buf)
goto end;
/* Copy sample fetch. This put the sample as const, the
* cast will copy data if a transformation is required.
*/
memcpy(&tmp, smp, sizeof(struct sample));
tmp.flags = SMP_F_CONST;
sink = (struct sink *)arg_p[1].data.str.area;
BUG_ON(!sink);
if (!sample_casts[smp->data.type][SMP_T_STR](&tmp))
fprintf(stderr, "(undisplayable)");
pfx = arg_p[0].data.str.area;
BUG_ON(!pfx);
else {
/* Display the displayable chars*. */
fputc('<', stderr);
for (i = 0; i < tmp.data.u.str.data; i++) {
if (isprint(tmp.data.u.str.area[i]))
fputc(tmp.data.u.str.area[i],
stderr);
else
fputc('.', stderr);
}
fputc('>', stderr);
}
}
fputc('\n', stderr);
chunk_printf(buf, "[debug] %s: type=%s ", pfx, smp_to_type[smp->data.type]);
if (!sample_casts[smp->data.type][SMP_T_STR])
goto nocast;
/* Copy sample fetch. This puts the sample as const, the
* cast will copy data if a transformation is required.
*/
memcpy(&tmp, smp, sizeof(struct sample));
tmp.flags = SMP_F_CONST;
if (!sample_casts[smp->data.type][SMP_T_STR](&tmp))
goto nocast;
/* Display the displayable chars*. */
b_putchr(buf, '<');
for (i = 0; i < tmp.data.u.str.data; i++) {
if (isprint(tmp.data.u.str.area[i]))
b_putchr(buf, tmp.data.u.str.area[i]);
else
b_putchr(buf, '.');
}
b_putchr(buf, '>');
done:
line = ist2(buf->area, buf->data);
sink_write(sink, &line, 1);
end:
free_trash_chunk(buf);
return 1;
nocast:
chunk_appendf(buf, "(undisplayable)");
goto done;
}
// This function checks the "debug" converter's arguments.
static int smp_check_debug(struct arg *args, struct sample_conv *conv,
const char *file, int line, char **err)
{
const char *name = "buf0";
struct sink *sink = NULL;
if (args[0].type != ARGT_STR) {
/* optional prefix */
args[0].data.str.area = "";
args[0].data.str.data = 0;
}
if (args[1].type == ARGT_STR)
name = args[1].data.str.area;
sink = sink_find(name);
if (!sink) {
memprintf(err, "No such sink '%s'", name);
return 0;
}
args[1].data.str.area = (char *)sink;
args[1].data.str.data = 0; // that's not a string anymore
return 1;
}
#endif
static int sample_conv_base642bin(const struct arg *arg_p, struct sample *smp, void *private)
{
@ -3357,10 +3398,7 @@ INITCALL1(STG_REGISTER, sample_register_fetches, &smp_kws);
/* Note: must not be declared <const> as its list will be overwritten */
static struct sample_conv_kw_list sample_conv_kws = {ILH, {
#ifdef DEBUG_EXPR
{ "debug", sample_conv_debug, 0, NULL, SMP_T_ANY, SMP_T_ANY },
#endif
{ "debug", sample_conv_debug, ARG2(0,STR,STR), smp_check_debug, SMP_T_ANY, SMP_T_ANY },
{ "b64dec", sample_conv_base642bin,0, NULL, SMP_T_STR, SMP_T_BIN },
{ "base64", sample_conv_bin2base64,0, NULL, SMP_T_BIN, SMP_T_STR },
{ "upper", sample_conv_str2upper, 0, NULL, SMP_T_STR, SMP_T_STR },