minor: fixed debug message on config.json version mismatch

This should help monitor the use of the link shortener, in particular
for nefarious uses.
Prompted to do this by https://app.y.gy/blog/honeypot

Cargo.lock

@@ -838,7 +838,7 @@ dependencies = [
 
 [[package]]
 name = "lonk"
-version = "1.0.1"
+version = "2.0.1"
 dependencies = [
  "argh",
  "async-object-pool",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "lonk"
-version = "1.0.1"
+version = "2.0.1"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

data/config.json

@@ -1,5 +1,5 @@
 {
-  "version": 1,
+  "version": 2,
   "db": {
     "address": "redis://redis:6379",
     "expire_seconds": 259200
@@ -10,7 +10,8 @@
   },
   "log_rules": {
     "error_log_file": "/data/log/error.log",
-    "access_log_file": "/data/log/access.log"
+    "access_log_file": "/data/log/access.log",
+    "link_log_file": "/data/log/link.log"
   },
   "serve_rules": {
     "dir": {

src/main.rs

@@ -142,8 +142,10 @@ mod conf {
     pub struct LogRules {
         /// Where to write error logs to. The file will be appended to.
         pub error_log_file: PathBuf,
-        /// Where to write access ogs to. The file will be appended to.
+        /// Where to write access logs to. The file will be appended to.
         pub access_log_file: PathBuf,
+        /// Where to write link shortening logs to. The file will be appended to.
+        pub link_log_file: PathBuf,
     }
 
     #[derive(Deserialize, Serialize, Debug, Clone)]
@@ -183,6 +185,7 @@ mod conf {
         ServeDirNotExists(PathBuf),
         AccessLogDirectoryNotExists(PathBuf),
         ErrorLogDirectoryNotExists(PathBuf),
+        LinkLogDirectoryNotExists(PathBuf),
     }
 
     impl Config {
@@ -223,24 +226,27 @@ mod conf {
             }
 
             // Check access and error log parent directories
+            fn check_exists<E>(path: &PathBuf, to_err: impl FnOnce(PathBuf) -> E) -> Result<(), E> {
+                let weak_canonical = normalize_path(path);
+                if let Some(parent) = weak_canonical.parent() {
+                    if !parent.exists() {
+                        return Err(to_err(parent.to_path_buf()));
+                    }
+                }
+                Ok(())
+            }
             // - Access log file
-            let weak_canonical = normalize_path(&self.log_rules.access_log_file);
-            if let Some(parent) = weak_canonical.parent() {
-                if !parent.exists() {
-                    return Err(ConfigParseError::AccessLogDirectoryNotExists(
-                        parent.to_path_buf(),
-                    ));
-                }
-            }
+            check_exists(&self.log_rules.access_log_file, |path| {
+                ConfigParseError::AccessLogDirectoryNotExists(path)
+            })?;
             // - Error log file
-            let weak_canonical = normalize_path(&self.log_rules.error_log_file);
-            if let Some(parent) = weak_canonical.parent() {
-                if !parent.exists() {
-                    return Err(ConfigParseError::ErrorLogDirectoryNotExists(
-                        parent.to_path_buf(),
-                    ));
-                }
-            }
+            check_exists(&self.log_rules.error_log_file, |path| {
+                ConfigParseError::ErrorLogDirectoryNotExists(path)
+            })?;
+            // - Link log file
+            check_exists(&self.log_rules.link_log_file, |path| {
+                ConfigParseError::LinkLogDirectoryNotExists(path)
+            })?;
 
             Ok(self)
         }
@@ -308,8 +314,8 @@ mod conf {
                     eprintln!(
                         concat!("Configuration file has outdated version.\n",
                         "Expected version field to be {} but got {}."),
+                        config_version(),
                         old_version,
-                        config_version()
                     );
                 }
                 ConfigParseError::ServeDirNotExists(dir) => {
@@ -342,6 +348,9 @@ mod conf {
                 ConfigParseError::ErrorLogDirectoryNotExists(dir) => {
                     eprintln!("Error log file should have parent directory {}, but this directory does not exist.", dir.to_string_lossy())
                 }
+                ConfigParseError::LinkLogDirectoryNotExists(dir) => {
+                    eprintln!("Link registration log file should have parent directory {}, but this directory does not exist.", dir.to_string_lossy())
+                }
             }
             std::process::exit(1);
         }
@@ -406,6 +415,7 @@ mod conf {
             Self {
                 error_log_file: "/etc/lonk/log/error.log".into(),
                 access_log_file: "/etc/lonk/log/access.log".into(),
+                link_log_file: "/etc/lonk/log/links.log".into(),
             }
         }
     }
@@ -924,6 +934,7 @@ mod service {
         pub struct Logger {
             access_tx: sync::mpsc::UnboundedSender<String>,
             error_tx: sync::mpsc::UnboundedSender<String>,
+            link_tx:  sync::mpsc::UnboundedSender<String>,
         }
 
         impl Logger {
@@ -931,6 +942,7 @@ mod service {
                 // Create the communication channels
                 let (access_tx, access_rx) = sync::mpsc::unbounded_channel::<String>();
                 let (error_tx, error_rx) = sync::mpsc::unbounded_channel::<String>();
+                let (link_tx, link_rx) = sync::mpsc::unbounded_channel::<String>();
 
                 // Start the logging tasks
                 tokio::spawn(Self::logging_task(
@@ -938,11 +950,13 @@ mod service {
                     config.access_log_file.clone(),
                 ));
                 tokio::spawn(Self::logging_task(error_rx, config.error_log_file.clone()));
+                tokio::spawn(Self::logging_task(link_rx, config.link_log_file.clone()));
 
                 // Done
                 Logger {
                     access_tx,
                     error_tx,
+                    link_tx,
                 }
             }
 
@@ -965,6 +979,16 @@ mod service {
             pub fn error(&self, msg: String) -> Result<(), ()> {
                 self.error_tx.send(msg).map_err(|_| ())
             }
+            
+            /// Log a message into the link log file.
+            ///
+            /// Returns a Result with empty type; if posting the log message
+            /// failed for any reason, it's unlikely to recover, and the user
+            /// should decide either to stop logging, ignore these errors, or
+            /// halt the program.
+            pub fn link(&self, msg: String) -> Result<(), ()> {
+                self.link_tx.send(msg).map_err(|_| ())
+            }
 
             /// The task responsible for receiving the log messages and actually
             /// writing them into the corresponding files. One task is created
@@ -1068,7 +1092,7 @@ async fn shorten(
         Ok(result) => match result {
             service::db::AddResult::Success(slug) => {
                 logger
-                    .access(format!("{} -> {}\n", slug.inner_str(), url))
+                    .link(format!("{} -> {}\n", slug.inner_str(), url))
                     .ok();
                 Ok(slug)
             }
@@ -1237,8 +1261,7 @@ async fn serve() {
     // GET /
     // This should be the last thing matched, so that anything that doesn't
     //  match another filter will try to match a file.
-    let homepage = warp::get()
-        .and(config.serve_rules.dir.to_filter());
+    let homepage = warp::get().and(config.serve_rules.dir.to_filter());
 
     let get_routes = warp::get().and(link.or(homepage));
     let post_routes = warp::post().and(shorten);