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cleanup(userspace/engine): prometheus compliant regex parsing for metrics interval

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Signed-off-by: Melissa Kilby <melissa.kilby.oss@gmail.com>
This commit is contained in:
Melissa Kilby
2023-05-21 13:36:02 +00:00
committed by poiana
parent 698ff25f1e
commit 8e0c89d3b4
1 changed files with 75 additions and 89 deletions
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120
userspace/engine/falco_utils.cpp
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@@ -25,15 +25,10 @@ limitations under the License.
#include <re2/re2.h>
// these follow the POSIX standard
#define RGX_PROMETHEUS_TIME_DURATION_PATTERN "([0-9]+[a-z]+)"
#define RGX_PROMETHEUS_NUMBER_PATTERN "([0-9]+)"
#define RGX_PROMETHEUS_UNIT_PATTERN "([a-z]+)"
#define RGX_PROMETHEUS_TIME_DURATION "^((?P<y>[0-9]+)y)?((?P<w>[0-9]+)w)?((?P<d>[0-9]+)d)?((?P<h>[0-9]+)h)?((?P<m>[0-9]+)m)?((?P<s>[0-9]+)s)?((?P<ms>[0-9]+)ms)?$"
// using pre-compiled regex for better performance
static re2::RE2 s_rgx_prometheus_time_duration(RGX_PROMETHEUS_TIME_DURATION_PATTERN, re2::RE2::POSIX);
static re2::RE2 s_rgx_prometheus_number(RGX_PROMETHEUS_NUMBER_PATTERN, re2::RE2::POSIX);
static re2::RE2 s_rgx_prometheus_unit(RGX_PROMETHEUS_UNIT_PATTERN, re2::RE2::POSIX);
// using pre-compiled regex
static re2::RE2 s_rgx_prometheus_time_duration(RGX_PROMETHEUS_TIME_DURATION);
// Prometheus time durations: https://prometheus.io/docs/prometheus/latest/querying/basics/#time-durations
#define PROMETHEUS_UNIT_Y "y" ///> assuming a year has always 365d
@@ -45,12 +40,13 @@ static re2::RE2 s_rgx_prometheus_unit(RGX_PROMETHEUS_UNIT_PATTERN, re2::RE2::POS
#define PROMETHEUS_UNIT_MS "ms" ///> millisecond
// standard time unit conversions to milliseconds
#define SECOND_TO_MS 1000
#define MINUTE_TO_MS SECOND_TO_MS * 60
#define HOUR_TO_MS MINUTE_TO_MS * 60
#define DAY_TO_MS HOUR_TO_MS * 24
#define WEEK_TO_MS DAY_TO_MS * 7
#define YEAR_TO_MS DAY_TO_MS * 365
#define ONE_MS_TO_MS 1UL
#define ONE_SECOND_TO_MS 1000UL
#define ONE_MINUTE_TO_MS ONE_SECOND_TO_MS * 60UL
#define ONE_HOUR_TO_MS ONE_MINUTE_TO_MS * 60UL
#define ONE_DAY_TO_MS ONE_HOUR_TO_MS * 24UL
#define ONE_WEEK_TO_MS ONE_DAY_TO_MS * 7UL
#define ONE_YEAR_TO_MS ONE_DAY_TO_MS * 365UL
namespace falco
{
@@ -72,71 +68,61 @@ uint64_t parse_prometheus_interval(std::string interval_str)
/* todo: deprecate for Falco 0.36. */
interval = std::stoull(interval_str, nullptr, 0);
}
/* Option 2: Passing a Prometheus time duration.
/* Option 2: Passing a Prometheus compliant time duration.
* https://prometheus.io/docs/prometheus/latest/querying/basics/#time-durations
*/
else
{
re2::StringPiece input(interval_str);
std::string r;
std::string cur_interval_str;
uint64_t cur_interval;
std::string cur_unit;
bool valid = true;
/* Note that parsing is done at start up only. */
while(re2::RE2::FindAndConsume(&input, s_rgx_prometheus_time_duration, &r))
std::string args[14];
re2::RE2::Arg arg0(&args[0]);
re2::RE2::Arg arg1(&args[1]);
re2::RE2::Arg arg2(&args[2]);
re2::RE2::Arg arg3(&args[3]);
re2::RE2::Arg arg4(&args[4]);
re2::RE2::Arg arg5(&args[5]);
re2::RE2::Arg arg6(&args[6]);
re2::RE2::Arg arg7(&args[7]);
re2::RE2::Arg arg8(&args[8]);
re2::RE2::Arg arg9(&args[9]);
re2::RE2::Arg arg10(&args[10]);
re2::RE2::Arg arg11(&args[11]);
re2::RE2::Arg arg12(&args[12]);
re2::RE2::Arg arg13(&args[13]);
const re2::RE2::Arg* const matches[14] = {&arg0, &arg1, &arg2, &arg3, &arg4, &arg5, &arg6, &arg7, &arg8, &arg9, &arg10, &arg11, &arg12, &arg13};
const std::map<std::string, int>& named_groups = s_rgx_prometheus_time_duration.NamedCapturingGroups();
int num_groups = s_rgx_prometheus_time_duration.NumberOfCapturingGroups();
re2::RE2::FullMatchN(input, s_rgx_prometheus_time_duration, matches, num_groups);
static const char* all_prometheus_units[7] = {
PROMETHEUS_UNIT_Y, PROMETHEUS_UNIT_W, PROMETHEUS_UNIT_D, PROMETHEUS_UNIT_H,
PROMETHEUS_UNIT_M, PROMETHEUS_UNIT_S, PROMETHEUS_UNIT_MS };
static const uint64_t all_prometheus_time_conversions[7] = {
ONE_YEAR_TO_MS, ONE_WEEK_TO_MS, ONE_DAY_TO_MS, ONE_HOUR_TO_MS,
ONE_MINUTE_TO_MS, ONE_SECOND_TO_MS, ONE_MS_TO_MS };
for(size_t i = 0; i < sizeof(all_prometheus_units) / sizeof(const char*); i++)
{
std::string cur_interval_str;
uint64_t cur_interval = 0;
const auto &group_it = named_groups.find(all_prometheus_units[i]);
if(group_it != named_groups.end())
{
cur_interval_str = args[group_it->second - 1];
if(!cur_interval_str.empty())
{
RE2::Extract(r, s_rgx_prometheus_number, "\\1", &cur_interval_str);
cur_interval = std::stoull(cur_interval_str, nullptr, 0);
}
if(cur_interval > 0)
{
RE2::Extract(r, s_rgx_prometheus_unit, "\\1", &cur_unit);
if(cur_unit == PROMETHEUS_UNIT_MS)
{
interval += cur_interval;
}
else if(cur_unit == PROMETHEUS_UNIT_S)
{
interval += cur_interval * SECOND_TO_MS;
}
else if(cur_unit == PROMETHEUS_UNIT_M)
{
interval += cur_interval * MINUTE_TO_MS;
}
else if(cur_unit == PROMETHEUS_UNIT_H)
{
interval += cur_interval * HOUR_TO_MS;
}
else if(cur_unit == PROMETHEUS_UNIT_D)
{
interval += cur_interval * DAY_TO_MS;
}
else if(cur_unit == PROMETHEUS_UNIT_W)
{
interval += cur_interval * WEEK_TO_MS;
}
else if(cur_unit == PROMETHEUS_UNIT_Y)
{
interval += cur_interval * YEAR_TO_MS;
}
else
{
valid = false;
}
}
else
{
valid = false;
}
}
if (!valid)
{
// invalidate if any invalid unit or no corresponding numeric value was found
interval = 0;
interval += cur_interval * all_prometheus_time_conversions[i];
}
}
}
}
}
return interval;
}