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use std::process;
use batcher::{BatchConfigBuilder, BatchDriver, BatchDriverInput, BatchDriverOutput, Batcher};
use mqtt_channel::{Connection, Message, QoS, SinkExt, StreamExt, Topic, TopicFilter};
use serde_json::json;
use time::OffsetDateTime;
use tracing::{error, info, instrument};
use super::{batcher::MessageBatch, collectd::CollectdMessage, error::DeviceMonitorError};
const DEFAULT_HOST: &str = "localhost";
const DEFAULT_PORT: u16 = 1883;
const DEFAULT_MQTT_CLIENT_ID: &str = "collectd-mapper";
const DEFAULT_BATCHING_WINDOW: u32 = 500;
const DEFAULT_MAXIMUM_MESSAGE_DELAY: u32 = 400; // Heuristic delay that should work out well on an Rpi
const DEFAULT_MESSAGE_LEAP_LIMIT: u32 = 0;
const DEFAULT_MQTT_SOURCE_TOPIC: &str = "collectd/#";
const DEFAULT_MQTT_TARGET_TOPIC: &str = "tedge/measurements";
const COMMON_HEALTH_CHECK_TOPIC: &str = "tedge/health-check";
const HEALTH_CHECK_TOPIC: &str = "tedge/health-check/tedge-mapper-collectd";
const HEALTH_STATUS_TOPIC: &str = "tedge/health/tedge-mapper-collectd";
#[derive(Debug)]
pub struct DeviceMonitorConfig {
host: String,
port: u16,
mqtt_client_id: &'static str,
pub mqtt_source_topic: &'static str,
mqtt_target_topic: &'static str,
batching_window: u32,
maximum_message_delay: u32,
message_leap_limit: u32,
}
impl Default for DeviceMonitorConfig {
fn default() -> Self {
Self {
host: DEFAULT_HOST.to_string(),
port: DEFAULT_PORT,
mqtt_client_id: DEFAULT_MQTT_CLIENT_ID,
mqtt_source_topic: DEFAULT_MQTT_SOURCE_TOPIC,
mqtt_target_topic: DEFAULT_MQTT_TARGET_TOPIC,
batching_window: DEFAULT_BATCHING_WINDOW,
maximum_message_delay: DEFAULT_MAXIMUM_MESSAGE_DELAY,
message_leap_limit: DEFAULT_MESSAGE_LEAP_LIMIT,
}
}
}
impl DeviceMonitorConfig {
pub fn with_port(self, port: u16) -> Self {
Self { port, ..self }
}
pub fn with_host(self, host: String) -> Self {
Self { host, ..self }
}
}
#[derive(Debug)]
pub struct DeviceMonitor {
device_monitor_config: DeviceMonitorConfig,
}
impl DeviceMonitor {
pub fn new(device_monitor_config: DeviceMonitorConfig) -> Self {
Self {
device_monitor_config,
}
}
#[instrument(skip(self), name = "monitor")]
pub async fn run(&self) -> Result<(), DeviceMonitorError> {
let health_check_topics: TopicFilter = vec![COMMON_HEALTH_CHECK_TOPIC, HEALTH_CHECK_TOPIC]
.try_into()
.expect("Valid health topics");
let health_status_topic = Topic::new_unchecked(HEALTH_STATUS_TOPIC);
let mut input_topic = TopicFilter::new(self.device_monitor_config.mqtt_source_topic)?
.with_qos(QoS::AtMostOnce);
input_topic.add_all(health_check_topics.clone());
let mqtt_config = mqtt_channel::Config::new(
self.device_monitor_config.host.to_string(),
self.device_monitor_config.port,
)
.with_session_name(self.device_monitor_config.mqtt_client_id)
.with_subscriptions(input_topic);
let mqtt_client = Connection::new(&mqtt_config).await?;
let batch_config = BatchConfigBuilder::new()
.event_jitter(self.device_monitor_config.batching_window)
.delivery_jitter(self.device_monitor_config.maximum_message_delay)
.message_leap_limit(self.device_monitor_config.message_leap_limit)
.build();
let (msg_send, msg_recv) = tokio::sync::mpsc::channel(100);
let (batch_send, mut batch_recv) = tokio::sync::mpsc::channel(100);
let driver = BatchDriver::new(Batcher::new(batch_config), msg_recv, batch_send);
let driver_join_handle = tokio::task::spawn(async move {
match driver.run().await {
Ok(_) => error!("Unexpected end of message batcher thread"),
Err(err) => error!("Error in message batcher thread: {}", err),
}
});
let mut collectd_messages = mqtt_client.received;
let mut output_messages = mqtt_client.published.clone();
let input_join_handle = tokio::task::spawn(async move {
while let Some(message) = collectd_messages.next().await {
if health_check_topics.accept(&message) {
let health_status = json!({
"status": "up",
"pid": process::id(),
"time": OffsetDateTime::now_utc().unix_timestamp(),
})
.to_string();
let health_message = Message::new(&health_status_topic, health_status);
let _ = output_messages.send(health_message).await;
} else {
match CollectdMessage::parse_from(&message) {
Ok(collectd_message) => {
for msg in collectd_message {
let batch_input = BatchDriverInput::Event(msg);
if let Err(err) = msg_send.send(batch_input).await {
error!("Error while processing a collectd message: {}", err);
}
}
}
Err(err) => {
error!("Error while decoding a collectd message: {}", err);
}
}
}
}
// The MQTT connection has been closed by the process itself.
info!("Stop batching");
let eof = BatchDriverInput::Flush;
msg_send.send(eof).await
});
let output_topic = Topic::new(self.device_monitor_config.mqtt_target_topic)?;
let mut output_messages = mqtt_client.published;
let output_join_handle = tokio::task::spawn(async move {
loop {
match batch_recv.recv().await {
None | Some(BatchDriverOutput::Flush) => {
break;
}
Some(BatchDriverOutput::Batch(messages)) => {
match MessageBatch::thin_edge_json_bytes(messages) {
Ok(payload) => {
let tedge_message = Message::new(&output_topic, payload);
if let Err(err) = output_messages.send(tedge_message).await {
error!("Error while sending a thin-edge json message: {}", err);
}
}
Err(err) => {
error!("Error while encoding a thin-edge json message: {}", err);
}
}
}
}
}
// All the messages forwarded for batching have been processed.
info!("Batching done");
});
let mut mqtt_errors = mqtt_client.errors;
let error_join_handle = tokio::task::spawn(async move {
while let Some(error) = mqtt_errors.next().await {
error!("MQTT error: {}", error);
}
});
let _ = driver_join_handle.await;
let _ = input_join_handle.await;
let _ = output_join_handle.await;
let _ = error_join_handle.await;
Ok(())
}
}
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