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|
use crate::converter::*;
use crate::error::*;
use flockfile::{check_another_instance_is_not_running, Flockfile};
use mqtt_client::{Client, MqttClient, MqttClientError};
use tedge_config::{ConfigSettingAccessor, MqttPortSetting, TEdgeConfig};
use tokio::task::JoinHandle;
use tracing::{error, info, instrument};
pub async fn create_mapper<'a>(
app_name: &'a str,
tedge_config: &'a TEdgeConfig,
converter: Box<dyn Converter<Error = ConversionError>>,
) -> Result<Mapper, anyhow::Error> {
let flock = check_another_instance_is_not_running(app_name)?;
info!("{} starting", app_name);
let mqtt_config = mqtt_config(tedge_config)?;
let mqtt_client = Client::connect(app_name, &mqtt_config).await?;
Ok(Mapper::new(mqtt_client, converter, flock))
}
pub(crate) fn mqtt_config(
tedge_config: &TEdgeConfig,
) -> Result<mqtt_client::Config, anyhow::Error> {
Ok(mqtt_client::Config::default().with_port(tedge_config.query(MqttPortSetting)?.into()))
}
pub struct Mapper {
client: mqtt_client::Client,
converter: Box<dyn Converter<Error = ConversionError>>,
_flock: Flockfile,
}
impl Mapper {
pub fn new(
client: mqtt_client::Client,
converter: Box<dyn Converter<Error = ConversionError>>,
_flock: Flockfile,
) -> Self {
Self {
client,
converter,
_flock,
}
}
pub(crate) async fn run(&mut self) -> Result<(), MqttClientError> {
info!("Running");
let errors_handle = self.subscribe_errors();
let messages_handle = self.subscribe_messages();
messages_handle.await?;
errors_handle
.await
.map_err(|_| MqttClientError::JoinError)?;
Ok(())
}
#[instrument(skip(self), name = "errors")]
fn subscribe_errors(&self) -> JoinHandle<()> {
let mut errors = self.client.subscribe_errors();
tokio::spawn(async move {
while let Some(error) = errors.next().await {
error!("{}", error);
}
})
}
#[instrument(skip(self), name = "messages")]
async fn subscribe_messages(&mut self) -> Result<(), MqttClientError> {
let init_messages = self.converter.init_messages();
for init_message in init_messages.into_iter() {
self.client.publish(init_message).await?
}
let mut messages = self
.client
.subscribe(self.converter.get_in_topic_filter().clone())
.await?;
while let Some(message) = messages.next().await {
let converted_messages = self.converter.convert(&message);
for converted_message in converted_messages.into_iter() {
self.client.publish(converted_message).await?
}
}
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use mqtt_client::{Message, Topic, TopicFilter};
use std::time::Duration;
use tokio::time::sleep;
#[tokio::test]
#[serial_test::serial]
async fn a_valid_input_leads_to_a_translated_output() -> Result<(), anyhow::Error> {
// Given an MQTT broker
let broker = mqtt_tests::test_mqtt_broker();
// Given a mapper
let name = "mapper_under_test";
let flock = check_another_instance_is_not_running(name)
.expect("Another mapper instance is locking /run/lock/mapper_under_test.lock");
let mqtt_config = mqtt_client::Config::default().with_port(broker.port);
let mqtt_client = Client::connect(name, &mqtt_config).await?;
let mut mapper = Mapper {
client: mqtt_client,
converter: Box::new(UppercaseConverter::new()),
_flock: flock,
};
// Let's run the mapper in the background
tokio::spawn(async move {
let _ = mapper.run().await;
});
sleep(Duration::from_secs(1)).await;
// One can now send requests
let timeout = Duration::from_secs(1);
// Happy path
let input = "abcde";
let expected = Some("ABCDE".to_string());
let actual = broker
.wait_for_response_on_publish("in_topic", input, "out_topic", timeout)
.await;
assert_eq!(expected, actual);
// Ill-formed input
let input = "éèê";
let expected = Some(format!("{}", UppercaseConverter::conversion_error()));
let actual = broker
.wait_for_response_on_publish("in_topic", input, "err_topic", timeout)
.await;
assert_eq!(expected, actual);
Ok(())
}
struct UppercaseConverter {
mapper_config: MapperConfig,
}
impl UppercaseConverter {
pub fn new() -> UppercaseConverter {
let mapper_config = MapperConfig {
in_topic_filter: TopicFilter::new("in_topic").expect("invalid topic filter"),
out_topic: Topic::new_unchecked("out_topic"),
errors_topic: Topic::new_unchecked("err_topic"),
};
UppercaseConverter { mapper_config }
}
pub fn conversion_error() -> ConversionError {
// Just a stupid error that matches the expectations of the mapper
ConversionError::FromMapper(MapperError::HomeDirNotFound)
}
}
impl Converter for UppercaseConverter {
type Error = ConversionError;
fn get_mapper_config(&self) -> &MapperConfig {
&self.mapper_config
}
fn try_convert(&mut self, input: &Message) -> Result<Vec<Message>, Self::Error> {
let input = input.payload_str().expect("utf8");
if input.is_ascii() {
let msg = vec![Message::new(
&self.mapper_config.out_topic,
input.to_uppercase(),
)];
Ok(msg)
} else {
Err(UppercaseConverter::conversion_error())
}
}
}
}
|
