feat(config): Allow loading config from JSON file

Author: alixinne

src/main.rs

@@ -1,6 +1,8 @@
 #[macro_use]
 extern crate log;
 
+use std::path::PathBuf;
+
 use structopt::StructOpt;
 use tokio::runtime::Builder;
 use tokio::signal;
@@ -11,16 +13,23 @@ struct Opts {
     verbose: u32,
     #[structopt(short, long = "db-path")]
     database_path: Option<String>,
+    #[structopt(short, long = "config")]
+    config_path: Option<PathBuf>,
     #[structopt(long)]
     dump_config: bool,
 }
 
 async fn run(opts: Opts) -> color_eyre::eyre::Result<()> {
-    // Connect to database
-    let mut db = hyperion::db::Db::try_default(opts.database_path.as_deref()).await?;
-
     // Load configuration
-    let config = hyperion::models::Config::load(&mut db).await?;
+    let config = {
+        if let Some(config_path) = opts.config_path.as_deref() {
+            hyperion::models::Config::load_file(config_path).await?
+        } else {
+            // Connect to database
+            let mut db = hyperion::db::Db::try_default(opts.database_path.as_deref()).await?;
+            hyperion::models::Config::load(&mut db).await?
+        }
+    };
 
     // Dump configuration if this was asked
     if opts.dump_config {

src/models.rs

@@ -272,7 +272,7 @@ pub trait DeviceConfig {
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Validate)]
-#[serde(default)]
+#[serde(default, rename_all = "camelCase")]
 pub struct Dummy {
     #[validate(range(min = 1))]
     pub hardware_led_count: u32,
@@ -1374,6 +1374,8 @@ impl InstanceConfigCreator {
 
 #[derive(Debug, Error)]
 pub enum ConfigError {
+    #[error("i/o error: {0}")]
+    Io(#[from] std::io::Error),
     #[error("error querying the database: {0}")]
     Sqlx(#[from] sqlx::Error),
     #[error("error loading instance: {0}")]
@@ -1387,6 +1389,8 @@ pub enum ConfigError {
     // TODO: Say which setting?
     #[error("missing hyperion_inst field on instance setting")]
     MissingHyperionInst,
+    #[error("invalid JSON: {0}")]
+    Json(#[from] serde_json::Error),
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
@@ -1601,6 +1605,16 @@ impl Config {
         })
     }
 
+    pub async fn load_file(path: &std::path::Path) -> Result<Self, ConfigError> {
+        use tokio::io::AsyncReadExt;
+
+        let mut file = tokio::fs::File::open(path).await?;
+        let mut full = String::new();
+        file.read_to_string(&mut full).await?;
+
+        Ok(serde_json::from_str(&full)?)
+    }
+
     pub fn uuid(&self) -> uuid::Uuid {
         // There should always be a meta uuid
         self.meta.first().map(|meta| meta.uuid).unwrap_or_default()