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Emit zone-aware UTC timestamp with real sub-second (not naive local + fake .000000) #14

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Emit zone-aware UTC timestamp with real sub-second (not naive local + fake .000000) #14

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5dc60ad
Emit zone-aware UTC timestamp with real sub-second (was naive local +…
ACETyr Jun 14, 2026
7cb7807
Emit zone-aware UTC for the status-message timestamp too
ACETyr Jun 14, 2026
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71 changes: 44 additions & 27 deletions src/helpers/MQTTMessageBuilder.cpp
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#include "MQTTMessageBuilder.h"
#include <ArduinoJson.h>
#include <time.h>
#include <sys/time.h>
#include <Timezone.h>
#include "MeshCore.h"

Expand Down Expand Up @@ -168,18 +169,25 @@ int MQTTMessageBuilder::buildPacketJSON(
if (!packet) return 0;

// Get current device time (should be UTC since system timezone is set to UTC)
time_t now = time(nullptr);

// Convert to local time using timezone library (for timestamp field only)
time_t local_time = timezone ? timezone->toLocal(now) : now;
struct tm* local_timeinfo = localtime(&local_time);

// Format timestamp in ISO 8601 format (LOCAL TIME)
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
time_t now = now_tv.tv_sec;

// Packet timestamp is emitted as zone-aware UTC (RFC3339 "Zulu") via gmtime — not naive
// local time. (timezone is intentionally not applied here; see the timestamp comment below.)
struct tm* utc_ts_info = gmtime(&now);

// Zone-aware UTC (RFC3339 Zulu) with a REAL sub-second from gettimeofday(). The prior ".000000"
// was a hardcoded literal carrying no information; gettimeofday() yields genuine microseconds
// (SNTP-maintained on ESP32), useful for self-hosted logging/correlation. Aggregators that only
// need second resolution (e.g. CoreScope) simply truncate the fraction. Emitting UTC with an
// explicit Z (not naive local time) also stops such aggregators from clamping the value.
char timestamp[32];
if (local_timeinfo) {
strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S.000000", local_timeinfo);
if (utc_ts_info) {
size_t ts_len = strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S", utc_ts_info);
snprintf(timestamp + ts_len, sizeof(timestamp) - ts_len, ".%06ldZ", (long)now_tv.tv_usec);
} else {
strcpy(timestamp, "2024-01-01T12:00:00.000000");
strcpy(timestamp, "2024-01-01T12:00:00.000000Z");
}

// Get UTC time (since system timezone is UTC, time() returns UTC)
Expand Down Expand Up @@ -250,18 +258,25 @@ int MQTTMessageBuilder::buildPacketJSONFromRaw(
if (!packet || !raw_data || raw_len <= 0) return 0;

// Get current device time (should be UTC since system timezone is set to UTC)
time_t now = time(nullptr);

// Convert to local time using timezone library (for timestamp field only)
time_t local_time = timezone ? timezone->toLocal(now) : now;
struct tm* local_timeinfo = localtime(&local_time);

// Format timestamp in ISO 8601 format (LOCAL TIME)
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
time_t now = now_tv.tv_sec;

// Packet timestamp is emitted as zone-aware UTC (RFC3339 "Zulu") via gmtime — not naive
// local time. (timezone is intentionally not applied here; see the timestamp comment below.)
struct tm* utc_ts_info = gmtime(&now);

// Zone-aware UTC (RFC3339 Zulu) with a REAL sub-second from gettimeofday(). The prior ".000000"
// was a hardcoded literal carrying no information; gettimeofday() yields genuine microseconds
// (SNTP-maintained on ESP32), useful for self-hosted logging/correlation. Aggregators that only
// need second resolution (e.g. CoreScope) simply truncate the fraction. Emitting UTC with an
// explicit Z (not naive local time) also stops such aggregators from clamping the value.
char timestamp[32];
if (local_timeinfo) {
strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S.000000", local_timeinfo);
if (utc_ts_info) {
size_t ts_len = strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S", utc_ts_info);
snprintf(timestamp + ts_len, sizeof(timestamp) - ts_len, ".%06ldZ", (long)now_tv.tv_usec);
} else {
strcpy(timestamp, "2024-01-01T12:00:00.000000");
strcpy(timestamp, "2024-01-01T12:00:00.000000Z");
}

// Get UTC time (since system timezone is UTC, time() returns UTC)
Expand Down Expand Up @@ -327,18 +342,20 @@ int MQTTMessageBuilder::buildRawJSON(
if (!packet) return 0;

// Get current device time
time_t now = time(nullptr);
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
time_t now = now_tv.tv_sec;

// Convert to local time using timezone library
time_t local_time = timezone ? timezone->toLocal(now) : now;
struct tm* timeinfo = localtime(&local_time);
// Emit zone-aware UTC (RFC3339 Zulu) — consistent with the packet builders above.
struct tm* timeinfo = gmtime(&now);

// Format timestamp in ISO 8601 format
// Format timestamp as zone-aware UTC (RFC3339 Zulu) with real sub-second from gettimeofday()
char timestamp[32];
if (timeinfo) {
strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S.000000", timeinfo);
size_t ts_len = strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S", timeinfo);
snprintf(timestamp + ts_len, sizeof(timestamp) - ts_len, ".%06ldZ", (long)now_tv.tv_usec);
} else {
strcpy(timestamp, "2024-01-01T12:00:00.000000");
strcpy(timestamp, "2024-01-01T12:00:00.000000Z");
}

// Convert packet to hex
Expand Down
32 changes: 22 additions & 10 deletions src/helpers/bridges/MQTTBridge.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1480,12 +1480,18 @@ bool MQTTBridge::publishStatus() {
char timestamp[32];
char radio_info[64];

// Get current timestamp in ISO 8601 format
struct tm timeinfo;
if (getLocalTime(&timeinfo)) {
strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S.000000", &timeinfo);
// Zone-aware UTC timestamp (RFC3339 "Zulu") with a real sub-second from gettimeofday(), matching
// the packet builder (MQTTMessageBuilder). The prior ".000000" literal carried no sub-second and
// (with a local TZ set) could read as naive local; gmtime() + an explicit Z keeps it unambiguous UTC.
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
time_t now_sec = now_tv.tv_sec;
struct tm* utc_info = gmtime(&now_sec);
if (utc_info) {
size_t ts_len = strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S", utc_info);
snprintf(timestamp + ts_len, sizeof(timestamp) - ts_len, ".%06ldZ", (long)now_tv.tv_usec);
} else {
strcpy(timestamp, "2024-01-01T12:00:00.000000");
strcpy(timestamp, "2024-01-01T12:00:00.000000Z");
}

// Build radio info string (freq,bw,sf,cr)
Expand Down Expand Up @@ -2497,12 +2503,18 @@ void MQTTBridge::publishStatusToAnalyzerClient(PsychicMqttClient* client, const
char timestamp[32];
char radio_info[64];

// Get current timestamp in ISO 8601 format
struct tm timeinfo;
if (getLocalTime(&timeinfo)) {
strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S.000000", &timeinfo);
// Zone-aware UTC timestamp (RFC3339 "Zulu") with a real sub-second from gettimeofday(), matching
// the packet builder (MQTTMessageBuilder). The prior ".000000" literal carried no sub-second and
// (with a local TZ set) could read as naive local; gmtime() + an explicit Z keeps it unambiguous UTC.
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
time_t now_sec = now_tv.tv_sec;
struct tm* utc_info = gmtime(&now_sec);
if (utc_info) {
size_t ts_len = strftime(timestamp, sizeof(timestamp), "%Y-%m-%dT%H:%M:%S", utc_info);
snprintf(timestamp + ts_len, sizeof(timestamp) - ts_len, ".%06ldZ", (long)now_tv.tv_usec);
} else {
strcpy(timestamp, "2024-01-01T12:00:00.000000");
strcpy(timestamp, "2024-01-01T12:00:00.000000Z");
}

// Build radio info string (freq,bw,sf,cr)
Expand Down