beremiz

MQTT: added growing reconnect delay when connecting to broker fails.
default tip
8 months ago, Tomaz Orac
f83075f09e70
Parents bc39a871d356
Children
MQTT: added growing reconnect delay when connecting to broker fails.
1 files changed, 15 insertions(+), 4 deletions(-)
  • +15 -4
    mqtt/mqtt_template.c
    • --- a/mqtt/mqtt_template.c Thu Jun 26 16:48:59 2025 +0200
    +++ b/mqtt/mqtt_template.c Thu Sep 25 14:26:24 2025 +0200
    @@ -6,6 +6,7 @@
    #include <string.h>
    #include <stdio.h>
    #include <errno.h>
    +#include <math.h>
    #include "frozen.h"
    @@ -27,6 +28,8 @@
    #define LogError(...) _Log(LOG_CRITICAL, __VA_ARGS__);
    #define LogWarning(...) _Log(LOG_WARNING, __VA_ARGS__);
    +#define MIN(a, b) ((a) < (b) ? (a) : (b))
    +
    // Selected debug level for paho stack
    // can be:
    // MQTTCLIENT_TRACE_PROTOCOL, MQTTCLIENT_TRACE_MAXIMUM, MQTTCLIENT_TRACE_ERROR
    @@ -472,6 +475,12 @@
    static void *__MQTT_thread_proc(void *_unused) {{
    int rc = 0;
    + int attempt = 0;
    + /* TODO make parameters externally configurable */
    + int initialDelay = 5; /* seconds */
    + int maxDelay = 60;
    + int retry_delay = 0;
    + float factor = 1.5;
    while((rc = pthread_mutex_lock(&MQTT_thread_wakeup_mutex)) == 0 && !MQTT_stop_thread){{
    int do_publish;
    @@ -480,14 +489,16 @@
    if(MQTT_is_disconnected)
    {{
    - /* TODO growing retry delay */
    - /* TODO max retry delay as config parameter */
    - sleep(5);
    + /* Exponentially grow retry delay */
    + retry_delay = MIN(initialDelay * pow(factor, attempt), maxDelay);
    + sleep(retry_delay);
    rc = _connect_mqtt();
    if (rc == MQTTCLIENT_SUCCESS) {{
    + attempt = 0;
    LogInfo("MQTT Reconnected\n");
    }} else {{
    - LogError("MQTT Reconnect Failed, return code %d\n", rc);
    + attempt++;
    + LogError("MQTT Reconnecting failed, retrying in %d seconds, return code %d\n", retry_delay, rc);
    }}
    }}
    if(!MQTT_is_disconnected && MQTT_any_pub_var_changed)