Fix crashes after restart (#32)

Fix failed assertion after restart.

Fix Nginx crash loop caused by invalid DNS name.

The DNS name of a remote camera is validated before adding it to the database, but it's still possible for that name to change afterwards. In such cases, the corresponding Nginx config snippets written by lcsvc contained the no-longer-valid DNS name, which caused Nginx to fail to reload and, after a reboot, fail to start.

Fix is twofold. First, skip writing Nginx config snippets when remote cam is inaccessible. Second, relocate Nginx config snippets to /run. This ensures that, after a reboot, Nginx does not load potentially invalid configs before lcsvc has a chance to validate.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "lunacam"
-version = "1.0.0"
+version = "1.0.1"
 authors = ["Bobby Reynolds <bobby@reynoldsbd.net>"]
 license = "MIT OR Apache-2.0"
 edition = "2018"

src/cameras.rs

@@ -1,15 +1,14 @@
 //! Camera management
 
 
-use std::env;
 use std::fs;
 use std::path::Path;
 use std::sync::RwLock;
 
 use actix_web::http::{StatusCode};
 use actix_web::web::{self, Data, Json, ServiceConfig};
 use diesel::prelude::*;
-use log::{debug, error, info, trace};
+use log::{debug, error, info, trace, warn};
 use reqwest::Client;
 use serde::{Deserialize, Serialize};
 use tera::{Context, Tera};
@@ -92,7 +91,7 @@ fn put_camera(
         .first(&conn)?;
 
     if camera.enabled {
-        write_proxy_config(&camera, &templates)
+        write_proxy_config(&camera, &client, &templates)
             .and_then(|_| proxy::reload())
             .unwrap_or_else(|e|
                 error!("failed to configure proxy for camera {}: {}", camera.id, e)
@@ -260,7 +259,7 @@ fn patch_camera(
             .set(&camera)
             .execute(&conn)?;
         if camera.enabled {
-            write_proxy_config(&camera, &templates)
+            write_proxy_config(&camera, &client, &templates)
                 .unwrap_or_else(|e|
                     error!("failed to configure proxy for camera {}: {}", camera.id, e)
                 );
@@ -335,15 +334,32 @@ pub fn configure_api(service: &mut ServiceConfig) {
 /// Gets path of the proxy configuration file for the specified camera
 fn get_proxy_config_path(id: i32) -> Result<impl AsRef<Path>> {
 
-    let state_dir = env::var("STATE_DIRECTORY")?;
-    let path = format!("{}/nginx/proxy-{}.conf", state_dir, id);
+    let cfg_dir = proxy::config_dir()?;
+    let path = format!("{}/proxy-{}.conf", cfg_dir, id);
 
     Ok(path)
 }
 
 
 /// Writes or removes the proxy configuration file for this camera
-fn write_proxy_config(camera: &Camera, templates: &Tera) -> Result<()> {
+fn write_proxy_config(
+    camera: &Camera,
+    client: &Client,
+    templates: &Tera
+) -> Result<()> {
+
+    // Validate remote address before writing proxy config (otherwise, Nginx
+    // will fail to start/reload, potentially making the web UI inaccessible)
+    if !camera.local {
+        debug!("validating connection to camera {}", camera.id);
+        let url = format!("http://{}/api/stream", camera.address);
+        if let Err(err) = client.get(&url).send() {
+            // Misconfigured camera should not bring down the whole system
+            error!("failed to connect to camera {}: {}", camera.id, err);
+            warn!("skipping proxy configuration");
+            return Ok(());
+        }
+    }
 
     let mut context = Context::new();
     context.insert("camera", camera);
@@ -383,6 +399,7 @@ fn clear_proxy_config(id: i32) -> Result<()> {
 /// in this module.
 pub fn initialize(
     conn: &PooledConnection,
+    client: &Client,
     templates: &Tera,
     #[cfg(feature = "stream")]
     stream: &Stream,
@@ -392,7 +409,7 @@ pub fn initialize(
 
     for camera in &cameras {
         if camera.enabled {
-            write_proxy_config(&camera, templates)
+            write_proxy_config(&camera, client, templates)
                 .unwrap_or_else(|e|
                     error!("failed to configure proxy for camera {}: {}", camera.id, e)
                 );
@@ -410,6 +427,7 @@ pub fn initialize(
     #[cfg(feature = "stream")]
     {
         let local_cam_count = cameras.iter()
+            .filter(|c| c.local)
             .count();
 
         assert!(local_cam_count <= 1);

src/lcsvc.rs

@@ -13,7 +13,6 @@ use tera::Tera;
 use lunacam::cameras;
 use lunacam::db;
 use lunacam::error::Result;
-use lunacam::proxy;
 use lunacam::stream;
 use lunacam::ui;
 use lunacam::users;
@@ -58,8 +57,6 @@ fn main() -> Result<()> {
 
     init_logging();
 
-    proxy::init()?;
-
     let client    = Data::new(Client::new());
     let templates = Data::new(load_templates()?);
     let pool      = Data::new(db::connect()?);
@@ -73,6 +70,7 @@ fn main() -> Result<()> {
     if cfg!(feature = "portal") {
         cameras::initialize(
             &conn,
+            &client,
             &templates,
             #[cfg(feature = "stream")]
             &stream,

src/proxy.rs

@@ -10,24 +10,6 @@ use log::{debug, trace, warn};
 use crate::error::Result;
 
 
-/// Ensures the proxy config directory exists
-pub fn init() -> Result<()> {
-
-    trace!("identifying proxy config directory");
-    let state_dir = env::var("STATE_DIRECTORY")?;
-
-    let config_dir = format!("{}/nginx", state_dir);
-    trace!("checking for presence of proxy config directory {}", config_dir);
-    if fs::metadata(&config_dir).is_err() {
-
-        debug!("creating proxy config dir {}", config_dir);
-        fs::create_dir_all(&config_dir)?;
-    }
-
-    Ok(())
-}
-
-
 /// Reloads server configuration
 pub fn reload() -> Result<()> {
 
@@ -46,3 +28,21 @@ pub fn reload() -> Result<()> {
 
     Ok(())
 }
+
+
+/// Retrieves the proxy configuration directory, creating it if it does not yet
+/// exist.
+pub fn config_dir() -> Result<String> {
+
+    trace!("identifying proxy config directory");
+
+    let rt_dir = env::var("RUNTIME_DIRECTORY")?;
+    let cfg_dir = format!("{}/nginx", rt_dir);
+
+    if fs::metadata(&cfg_dir).is_err() {
+        debug!("creating proxy config directory {}", cfg_dir);
+        fs::create_dir_all(&cfg_dir)?;
+    }
+
+    Ok(cfg_dir)
+}

src/stream.rs

@@ -8,7 +8,6 @@
 use std::env;
 use std::fs;
 use std::io::Write;
-use std::path::Path;
 use std::process::{Command, Stdio};
 use std::sync::RwLock;
 
@@ -141,12 +140,10 @@ fn make_command(_orientation: Orientation) -> Result<Command> {
 
 
 /// Gets the location of the HLS stream's proxy configuration file
-fn get_proxy_config_path() -> Result<impl AsRef<Path>> {
+fn get_proxy_config_path() -> Result<String> {
 
-    trace!("identifying proxy config directory");
-    let state_dir = env::var("STATE_DIRECTORY")?;
-
-    let path = format!("{}/nginx/hls.conf", state_dir);
+    let cfg_dir = proxy::config_dir()?;
+    let path = format!("{}/hls.conf", cfg_dir);
 
     Ok(path)
 }

tools/pi-gen/common/02-web/files/nginx.conf

@@ -20,7 +20,7 @@ http {
         include /usr/share/lunacam/nginx/*.conf;
 
         # HLS reverse proxies
-        include /var/lib/lunacam/nginx/*.conf;
+        include /run/lunacam/nginx/*.conf;
 
         # LunaCam API
         location / {

tools/pi-gen/common/03-lcsvc/files/lcsvc.service

@@ -3,6 +3,7 @@ Description=LunaCam Service
 
 [Service]
 User=lunacam
+RuntimeDirectory=lunacam
 StateDirectory=lunacam
 Environment=LC_TEMPLATES=/usr/share/lunacam/templates
 ExecStart=/usr/bin/lcsvc