First step toward supporting multiple database writes

src/config.rs

@@ -45,20 +45,22 @@ pub struct UserAuth {
 }
 
 #[derive(Debug, Deserialize)]
-#[serde(rename_all = "camelCase")]
+#[serde(rename_all = "kebab-case", tag = "type")]
-pub struct InfluxDBConfig {
+pub enum Database {
-    pub url: String,
+    #[serde(rename_all = "camelCase")]
-    pub auth: Option<UserAuth>,
+    Influxdb {
-    pub db_name: String,
+        url: String,
-    pub measurement: String,
+        auth: Option<UserAuth>,
+        db_name: String,
+        measurement: String,
+    },
 }
 
 #[derive(Debug, Deserialize, Clone)]
-#[serde(rename_all = "camelCase", tag = "type")]
+#[serde(rename_all = "kebab-case", tag = "type")]
-#[allow(non_camel_case_types)]
 pub enum Payload {
     #[serde(rename_all = "camelCase")]
-    json {
+    Json {
         value_field_path: String,
         timestamp_field_path: Option<String>,
     },
@@ -79,7 +81,7 @@ pub struct Mapping {
 pub struct Config {
     pub log_level: Option<LevelFilter>,
     pub mqtt: MqttConfig,
-    pub database: InfluxDBConfig,
+    pub databases: Vec<Database>,
     pub mappings: Vec<Mapping>,
 }
 

src/main.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate log;
 
-use config::{Config, InfluxDBConfig, MqttAuth, MqttConfig, UserAuth};
+use config::{Config, Database as ConfigDatabase, MqttAuth, MqttConfig, UserAuth};
 use futures::TryFutureExt;
 use influxdb::InfluxDbWriteable;
 use influxdb::{Client as InfluxClient, Timestamp, Type};
@@ -89,15 +89,19 @@ async fn init_mqtt(config: &MqttConfig) -> Result<(MqttAsyncClient, MqttEventLoo
     Ok(MqttAsyncClient::new(options, 100))
 }
 
-fn init_db(config: &InfluxDBConfig) -> Result<Database, String> {
+fn init_db(config: &ConfigDatabase) -> Result<Database, String> {
-    let mut client = InfluxClient::new(config.url.clone(), config.db_name.clone());
+    match config {
-    if let Some(UserAuth { username, password }) = &config.auth {
+        ConfigDatabase::Influxdb { url, auth, db_name, measurement } => {
+            let mut client = InfluxClient::new(url.clone(), db_name.clone());
+            if let Some(UserAuth { username, password }) = auth {
                 client = client.with_auth(username, password);
             }
             Ok(Database {
                 client,
-        measurement: config.measurement.clone(),
+                measurement: measurement.clone(),
             })
+        }
+    }
 }
 
 async fn init_subscriptions(
@@ -121,7 +125,7 @@ async fn init_subscriptions(
 async fn handle_publish(
     publish: &Publish,
     mapping: Arc<Mapping>,
-    database: Arc<Database>,
+    databases: Arc<Vec<Database>>,
 ) -> Result<(), String> {
     debug!("Got publish: {:?}; {:?}", publish, publish.payload);
 
@@ -170,9 +174,11 @@ async fn handle_publish(
         .unwrap()
         .as_millis()
     );
+
+    for database in databases.iter() {
         let mut query = Timestamp::Milliseconds(timestamp)
             .into_query(&database.measurement)
-        .add_field(&field_name, influx_value);
+            .add_field(&field_name, influx_value.clone());
         for tag in mapping.tags.iter() {
             let value = match &tag.1 {
                 TagValue::Literal(v) => v.clone(),
@@ -189,6 +195,7 @@ async fn handle_publish(
             .await
             .map_err(|err| format!("Failed to write to DB: {}", err))?;
         debug!("wrote to influx: {:?}", query);
+    }
 
     Ok(())
 }
@@ -216,17 +223,20 @@ fn find_mapping<'a>(mappings: &'a Vec<Arc<Mapping>>, topic: &String) -> Option<&
 
 async fn run_event_loop(
     mut event_loop: MqttEventLoop,
-    mappings: &Vec<Arc<Mapping>>,
+    mappings: Vec<Mapping>,
-    database: Arc<Database>,
+    databases: Vec<Database>,
 ) {
+    let mappings = mappings.into_iter().map(Arc::new).collect();
+    let databases = Arc::new(databases);
+
     loop {
         match event_loop.poll().await {
             Ok(Event::Incoming(Packet::Publish(publish))) => {
                 if let Some(mapping) = find_mapping(&mappings, &publish.topic) {
                     let mapping = Arc::clone(mapping);
-                    let database = Arc::clone(&database);
+                    let databases = Arc::clone(&databases);
                     tokio::spawn(async move {
-                        if let Err(err) = handle_publish(&publish, mapping, database).await {
+                        if let Err(err) = handle_publish(&publish, mapping, databases).await {
                             warn!("{}", err);
                         }
                     });
@@ -256,14 +266,11 @@ async fn main() -> Result<(), String> {
     }
     logger_builder.init();
 
-    let mappings: Vec<Arc<Mapping>> = config
+    let mappings: Vec<Mapping> = config
         .mappings
         .iter()
         .map(Mapping::try_from)
-        .collect::<Result<Vec<Mapping>, String>>()?
+        .collect::<Result<Vec<Mapping>, String>>()?;
-        .into_iter()
-        .map(Arc::new)
-        .collect();
 
     let (mut mqtt_client, mqtt_event_loop) = init_mqtt(&config.mqtt).await?;
     init_subscriptions(
@@ -276,9 +283,12 @@ async fn main() -> Result<(), String> {
     )
     .await?;
 
-    let database = Arc::new(init_db(&config.database)?);
+    let databases = config.databases
+        .iter()
+        .map(init_db)
+        .collect::<Result<Vec<Database>, String>>()?;
 
-    run_event_loop(mqtt_event_loop, &mappings, database).await;
+    run_event_loop(mqtt_event_loop, mappings, databases).await;
 
     Ok(())
 }

src/mapping.rs

@@ -113,7 +113,7 @@ impl TryFrom<&ConfigMapping> for Mapping {
 
         let payload = match &mapping.payload {
             None => Payload::Raw,
-            Some(ConfigPayload::json { value_field_path, timestamp_field_path }) => {
+            Some(ConfigPayload::Json { value_field_path, timestamp_field_path }) => {
                 let value_field_selector = Selector::new(&value_field_path)
                     .map_err(|err| format!("Value field path '{}' is invalid: {}'", value_field_path, err))?;
                 let timestamp_field_selector = timestamp_field_path.as_ref()