Add stats serializer.

Makefile

@@ -11,5 +11,5 @@ clean:
 %.o: %.c *.h
 	$(CC) -c $(CFLAGS) $< -o $@
 
-adsbus: adsbus.o backend.o client.o airspy_adsb.o beast.o json.o common.o
-	$(CC) $(LDFLAGS) -o adsbus adsbus.o backend.o client.o airspy_adsb.o beast.o json.o common.o $(LIBS)
+adsbus: adsbus.o backend.o client.o airspy_adsb.o beast.o json.o stats.o common.o
+	$(CC) $(LDFLAGS) -o adsbus adsbus.o backend.o client.o airspy_adsb.o beast.o json.o stats.o common.o $(LIBS)

adsbus.c

@@ -11,6 +11,7 @@
 #include "airspy_adsb.h"
 #include "beast.h"
 #include "json.h"
+#include "stats.h"
 
 
 static bool add_dump(char *format) {
@@ -108,6 +109,7 @@ int main(int argc, char *argv[]) {
 	airspy_adsb_init();
 	beast_init();
 	json_init();
+	stats_init();
 
 	int epoll_fd = epoll_create1(0);
   if (epoll_fd == -1) {

client.c

@@ -7,6 +7,7 @@
 #include <fcntl.h>
 
 #include "json.h"
+#include "stats.h"
 #include "client.h"
 
 struct client {
@@ -24,8 +25,11 @@ struct serializer {
 	{
 		.name = "json",
 		.serialize = json_serialize,
-		.client_head = NULL,
 	},
+	{
+		.name = "stats",
+		.serialize = stats_serialize,
+	}
 };
 #define NUM_SERIALIZERS (sizeof(serializers) / sizeof(*serializers))
 

common.c

@@ -57,6 +57,12 @@ void buf_consume(struct buf *buf, size_t length) {
 }
 
 
+char *packet_type_names[] = {
+	"Mode-S short",
+	"Mode-S long",
+};
+
+
 uint64_t mlat_timestamp_scale_mhz_in(uint64_t timestamp, uint32_t mhz) {
 	return timestamp * (MLAT_MHZ / mhz);
 }

common.h

@@ -44,15 +44,16 @@ void buf_consume(struct buf *, size_t);
 struct backend;
 struct packet {
 	enum {
-		MODE_AC,
 		MODE_S_SHORT,
 		MODE_S_LONG,
+		NUM_TYPES,
 	} type;
 	uint8_t payload[DATA_LEN_MAX];
 	uint64_t mlat_timestamp;
 	uint32_t rssi;
 	struct backend *backend;
 };
+extern char *packet_type_names[];
 
 
 //////// mlat

json.c

@@ -14,7 +14,7 @@ void json_init() {
 	assert(JSON_INTEGER_IS_LONG_LONG);
 }
 
-static int json_buf_append_callback(const char *buffer, size_t size, void *data) {
+int json_buf_append_callback(const char *buffer, size_t size, void *data) {
 	struct buf *buf = data;
 	if (size > BUF_LEN_MAX - buf->length - 1) {
 		return -1;
@@ -70,9 +70,6 @@ void json_serialize(struct packet *packet, struct buf *buf) {
 	}
 
 	switch (packet->type) {
-		case MODE_AC:
-			break;
-
 		case MODE_S_SHORT:
 			json_serialize_mode_s_short(packet, buf);
 			break;
@@ -80,5 +77,8 @@ void json_serialize(struct packet *packet, struct buf *buf) {
 		case MODE_S_LONG:
 			json_serialize_mode_s_long(packet, buf);
 			break;
+
+		case NUM_TYPES:
+			break;
 	}
 }

json.h

@@ -5,3 +5,5 @@
 
 void json_init();
 void json_serialize(struct packet *, struct buf *);
+
+int json_buf_append_callback(const char *, size_t, void *);

stats.c

@@ -0,0 +1,43 @@
+#include <assert.h>
+#include <time.h>
+#include <jansson.h>
+
+#include "common.h"
+#include "backend.h"
+#include "json.h"
+#include "stats.h"
+
+
+static struct stats_state {
+	uint64_t total_count;
+	uint64_t type_count[NUM_TYPES];
+	struct timespec start;
+} stats_state = { 0 };
+
+
+void stats_init() {
+	assert(clock_gettime(CLOCK_MONOTONIC, &stats_state.start) == 0);
+}
+
+
+void stats_serialize(struct packet *packet, struct buf *buf) {
+	if (packet) {
+		stats_state.total_count++;
+		stats_state.type_count[packet->type]++;
+	}
+	if (stats_state.total_count % 1000 != 0) {
+		return;
+	}
+	json_t *counts = json_object();
+	for (int i = 0; i < NUM_TYPES; i++) {
+		json_object_set_new(counts, packet_type_names[i], json_integer(stats_state.type_count[i]));
+	}
+	struct timespec now;
+	assert(clock_gettime(CLOCK_MONOTONIC, &now) == 0);
+	json_t *out = json_pack("{sIso}",
+			"uptime_seconds", (json_int_t) (now.tv_sec - stats_state.start.tv_sec),
+			"packet_counts", counts);
+	assert(json_dump_callback(out, json_buf_append_callback, buf, 0) == 0);
+	json_decref(out);
+	buf_chr(buf, buf->length++) = '\n';
+}

stats.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include "common.h"
+
+
+void stats_init();
+void stats_serialize(struct packet *, struct buf *);