Add %F output format option to print timestamps in a human-readable format

format.c

@@ -26,6 +26,9 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <stdio.h>
+#include <time.h>
+
 #include "kcat.h"
 #include "rdendian.h"
 
@@ -136,6 +139,10 @@ void fmt_parse (const char *fmt) {
  fmt_add(KC_FMT_TIMESTAMP, NULL, 0);
  conf.flags |= CONF_F_APIVERREQ;
  break;
+ case 'D':
+ fmt_add(KC_FMT_FORMATTED_TIMESTAMP, NULL, 0);
+ conf.flags |= CONF_F_APIVERREQ;
+ break;
 #if HAVE_HEADERS
  case 'h':
  fmt_add(KC_FMT_HEADERS, NULL, 0);
@@ -370,6 +377,36 @@ static int unpack (FILE *fp, const char *what, const char *fmt,
 }
 
 
+/**
+ * Convert timestamp into a human-readable format.
+ */
+void format_timestamp(char *dst, size_t maxsize, int64_t unixtime_ms) {
+ time_t unixtime_secs = unixtime_ms / 1000;
+
+ struct tm *ts = localtime(&unixtime_secs);
+
+ size_t pos = strftime(dst, maxsize,
+ "%Y-%m-%dT%H:%M:%S.", ts);
+
+ if (pos == 0) {
+ return;
+ }
+
+ // add milliseconds
+ pos += snprintf(
+ &dst[pos],
+ maxsize-pos,
+ "%" PRId64,
+ unixtime_ms % 1000);
+
+ if (pos >= maxsize) {
+ return;
+ }
+
+ // add timezone
+ strftime(&dst[pos], maxsize-pos, "%z", ts);
+}
+
 
 
 /**
@@ -517,6 +554,24 @@ static void fmt_msg_output_str (FILE *fp,
  &tstype));
 #else
  r = fprintf(fp, "-1");
+#endif
+ break;
+ }
+
+ case KC_FMT_FORMATTED_TIMESTAMP:
+ {
+#if RD_KAFKA_VERSION >= 0x000902ff
+ rd_kafka_timestamp_type_t tstype;
+
+ char buf[80];
+ format_timestamp(buf,
+ sizeof(buf),
+ rd_kafka_message_timestamp(rkmessage,
+ &tstype));
+
+ r = fprintf(fp, "%s", buf);
+#else
+ r = fprintf(fp, "-1");
 #endif
  break;
  }

kcat.c

@@ -1434,6 +1434,7 @@ static void RD_NORETURN usage (const char *argv0, int exitcode,
  " %%K Message key length (or -1 for NULL)\n"
 #if RD_KAFKA_VERSION >= 0x000902ff
  " %%T Message timestamp (milliseconds since epoch UTC)\n"
+ " %%D Message timestamp (ISO8601 formatted)\n"
 #endif
 #if HAVE_HEADERS
  " %%h Message headers (n=v CSV)\n"

kcat.h

@@ -71,6 +71,7 @@ typedef enum {
  KC_FMT_TOPIC,
  KC_FMT_PARTITION,
  KC_FMT_TIMESTAMP,
+ KC_FMT_FORMATTED_TIMESTAMP,
  KC_FMT_HEADERS
 } fmt_type_t;