Give all subcommands option of returning a future to run in a Tokio context

src/commands/dump.rs

@@ -1,10 +1,9 @@
-use std::error::Error;
-
 use clap::{App, AppSettings, ArgMatches, SubCommand};
-use futures::Async;
+use futures::prelude::*;
 
 use super::stdin_stream;
 use webmetro::{
+    error::WebmetroError,
     stream_parser::StreamEbml,
     webm::{
         SimpleBlock,
@@ -18,7 +17,7 @@ pub fn options() -> App<'static, 'static> {
         .about("Dumps WebM parsing events from parsing stdin")
 }
 
-pub fn run(_args: &ArgMatches) -> Result<(), Box<Error>> {
+pub fn run(_args: &ArgMatches) -> Result<(), WebmetroError> {
 
     let mut events = stdin_stream().parse_ebml();
 

src/commands/filter.rs

@@ -1,12 +1,10 @@
 use std::{
-    error::Error,
     io,
     io::prelude::*
 };
 
 use clap::{App, Arg, ArgMatches, SubCommand};
 use futures::prelude::*;
-use tokio;
 
 use super::stdin_stream;
 use webmetro::{
@@ -27,8 +25,7 @@ pub fn options() -> App<'static, 'static> {
             .help("Slow down output to \"realtime\" speed as determined by the timestamps (useful for streaming)"))
 }
 
-pub fn run(args: &ArgMatches) -> Result<(), Box<Error>> {
-
+pub fn run(args: &ArgMatches) -> Box<Future<Item=(), Error=WebmetroError> + Send> {
     let mut chunk_stream: Box<Stream<Item = Chunk, Error = WebmetroError> + Send> = Box::new(
         stdin_stream()
         .parse_ebml()
@@ -40,12 +37,7 @@ pub fn run(args: &ArgMatches) -> Result<(), Box<Error>> {
         chunk_stream = Box::new(chunk_stream.throttle());
     }
 
-    tokio::run(chunk_stream.for_each(|chunk| {
+    Box::new(chunk_stream.for_each(|chunk| {
         io::stdout().write_all(chunk.as_ref()).map_err(WebmetroError::IoError)
-    }).map_err(|err| {
-        println!("Error: {}", err);
-        ::std::process::exit(1);
-    }));
-
-    Ok(())
+    }))
 }

src/commands/relay.rs

@@ -122,12 +122,19 @@ pub fn options() -> App<'static, 'static> {
             .required(true))
 }
 
-pub fn run(args: &ArgMatches) -> Result<(), Box<Error>> {
+pub fn run(args: &ArgMatches) -> Result<(), WebmetroError> {
     let single_channel = Channel::new();
 
     let addr_str = args.value_of("listen").ok_or("Listen address wasn't provided")?;
     let addr = addr_str.to_socket_addrs()?.next().ok_or("Listen address didn't resolve")?;
 
-    Http::new().bind(&addr, move || Ok(RelayServer(single_channel.clone())))?.run()?;
+    Http::new()
+        .bind(&addr, move || {
+            Ok(RelayServer(single_channel.clone()))
+        })
+        .map_err(|err| WebmetroError::Unknown(Box::new(err)))?
+        .run()
+        .map_err(|err| WebmetroError::Unknown(Box::new(err)))?;
+
     Ok(())
 }

src/error.rs

@@ -53,3 +53,10 @@ impl From<Box<Error + Send>> for WebmetroError {
         WebmetroError::Unknown(err)
     }
 }
+
+impl<'a> From<&'a str> for WebmetroError {
+    fn from(err: &'a str) -> WebmetroError {
+        let error: Box<Error + Send + Sync> = err.into();
+        WebmetroError::Unknown(error)
+    }
+}

src/main.rs

@@ -8,6 +8,9 @@ extern crate webmetro;
 mod commands;
 
 use clap::{App, AppSettings};
+use futures::prelude::*;
+use webmetro::error::WebmetroError;
+
 use commands::{
     relay,
     filter,
@@ -27,17 +30,26 @@ fn options() -> App<'static, 'static> {
 fn main() {
     let args = options().get_matches();
 
-    match args.subcommand() {
-        ("filter", Some(sub_args)) => filter::run(sub_args),
-        ("relay", Some(sub_args)) => relay::run(sub_args),
-        ("dump", Some(sub_args)) => dump::run(sub_args),
-        _ => {
+    tokio_run(match args.subcommand() {
+        ("filter", Some(sub_args)) => box_up(filter::run(sub_args)),
+        ("relay", Some(sub_args)) => box_up(relay::run(sub_args)),
+        ("dump", Some(sub_args)) => box_up(dump::run(sub_args)),
+        _ => box_up(futures::lazy(|| {
             options().print_help().unwrap();
             println!("");
             Ok(())
-        }
-    }.unwrap_or_else(|err| {
-        println!("Error: {}", err);
-        ::std::process::exit(1);
+        }))
     });
 }
+
+fn tokio_run(task: Box<Future<Item=(), Error=WebmetroError> + Send + 'static>) {
+    tokio::run(task.into_future().map_err(|err| {
+        eprintln!("Error: {}", err);
+        ::std::process::exit(1);
+    }));
+}
+
+fn box_up<F: IntoFuture<Item=(), Error=WebmetroError>>(task: F) -> Box<Future<Item=(), Error=WebmetroError> + Send + 'static>
+where F::Future: Send + 'static {
+    Box::new(task.into_future())
+}