add command to get the state of all rooms

src/error.rs

@@ -43,6 +43,9 @@ pub(crate) enum Main {
     #[error(transparent)]
     ServeCommand(#[from] ServeCommand),
 
+    #[error(transparent)]
+    DumpStateCommand(#[from] DumpStateCommand),
+
     #[error("failed to install global default tracing subscriber")]
     SetSubscriber(#[from] tracing::subscriber::SetGlobalDefaultError),
 
@@ -85,6 +88,28 @@ pub(crate) enum CheckConfigCommand {
     Config(#[from] Config),
 }
 
+/// Errors returned from the `dump-state` CLI subcommand.
+// Missing docs are allowed here since that kind of information should be
+// encoded in the error messages themselves anyway.
+#[allow(missing_docs)]
+#[derive(Error, Debug)]
+pub(crate) enum DumpStateCommand {
+    #[error("failed to load configuration")]
+    Config(#[from] Config),
+
+    #[error("failed to initialize services")]
+    InitializeServices(#[source] crate::utils::error::Error),
+
+    #[error("failed to load or create the database")]
+    Database(#[source] crate::utils::error::Error),
+
+    #[error("`server_name` change check failed")]
+    ServerNameChanged(#[from] ServerNameChanged),
+
+    #[error("failed to serialize state to stdout")]
+    Serialize(#[from] serde_json::Error),
+}
+
 /// Error generated if `server_name` has changed or if checking this failed
 // Missing docs are allowed here since that kind of information should be
 // encoded in the error messages themselves anyway.