improve cli error message (#372)

roapi/src/config.rs

@@ -136,7 +136,7 @@ fn config_arg() -> clap::Arg {
         .short('c')
 }
 
-fn get_cmd() -> clap::Command {
+pub fn get_cmd() -> clap::Command {
     clap::Command::new("roapi")
         .version(env!("CARGO_PKG_VERSION"))
         .author("QP Hou")
@@ -156,8 +156,8 @@ fn get_cmd() -> clap::Command {
         ])
 }
 
-pub fn get_configuration() -> Result<Config, Whatever> {
-    let matches = get_cmd().get_matches();
+pub fn get_configuration(cmd: clap::Command) -> Result<Config, Whatever> {
+    let matches = cmd.get_matches();
 
     let mut config: Config = match matches.get_one::<String>("config") {
         None => Config::default(),

roapi/src/context.rs

@@ -12,12 +12,22 @@ use columnq::error::QueryError;
 use columnq::table::TableSource;
 use columnq::ColumnQ;
 use log::info;
-use snafu::{whatever, Whatever};
+use snafu::prelude::*;
 use tokio::sync::RwLock;
 
 use crate::config::Config;
 use crate::error::ApiErrResp;
 
+#[derive(Debug, Snafu)]
+pub enum Error {
+    #[snafu(display("No table nor kvstore found in config"))]
+    NoData,
+    #[snafu(display("Failed to load table: {source}"))]
+    LoadTable { source: ColumnQError },
+    #[snafu(display("Failed to load kvstore: {source}"))]
+    LoadKvstore { source: ColumnQError },
+}
+
 pub struct RawRoapiContext {
     pub cq: ColumnQ,
     pub response_format: encoding::ContentType,
@@ -25,25 +35,25 @@ pub struct RawRoapiContext {
 }
 
 impl RawRoapiContext {
-    pub async fn new(config: &Config, read_only: bool) -> Result<Self, Whatever> {
+    pub async fn new(config: &Config, read_only: bool) -> Result<Self, Error> {
         let mut cq = match config.get_datafusion_config() {
             Ok(df_cfg) => ColumnQ::new_with_config(df_cfg, read_only),
             _ => ColumnQ::new_with_read_only(read_only),
         };
 
         if config.tables.is_empty() && config.kvstores.is_empty() {
-            whatever!("No table nor kvstore found in config");
+            return Err(Error::NoData);
         }
 
         for t in config.tables.iter() {
             info!("loading `{}` as table `{}`", t.io_source, t.name);
-            whatever!(cq.load_table(t).await, "Failed to load table");
+            cq.load_table(t).await.context(LoadTableSnafu)?;
             info!("registered `{}` as table `{}`", t.io_source, t.name);
         }
 
         for k in config.kvstores.iter() {
             info!("loading `{}` as kv store `{}`", k.io_source, k.name);
-            whatever!(cq.load_kv(k.clone()).await, "Failed to load kvstore");
+            cq.load_kv(k.clone()).await.context(LoadKvstoreSnafu)?;
             info!("registered `{}` as kv store `{}`", k.io_source, k.name);
         }
 

roapi/src/main.rs

@@ -1,24 +1,28 @@
 #![deny(warnings)]
 
-use roapi::config::get_configuration;
+use roapi::config::{get_cmd, get_configuration};
 use roapi::startup::Application;
-use snafu::{whatever, Whatever};
 
 #[cfg(feature = "snmalloc")]
 #[global_allocator]
 static ALLOC: snmalloc_rs::SnMalloc = snmalloc_rs::SnMalloc;
 
 #[tokio::main]
-async fn main() -> Result<(), Whatever> {
+async fn main() {
     env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info")).init();
 
-    let config = whatever!(get_configuration(), "Failed to load configuration");
-    let application = Application::build(config)
-        .await
-        .expect("Failed to build App");
-    application
-        .run_until_stopped()
-        .await
-        .expect("Failed to run App");
-    Ok(())
+    let mut cmd = get_cmd();
+
+    let re: Result<(), Box<dyn std::error::Error>> = async {
+        let cmd = cmd.clone();
+        let config = get_configuration(cmd)?;
+        let application = Application::build(config).await?;
+        application.run_until_stopped().await?;
+        Ok(())
+    }
+    .await;
+    if let Err(e) = re {
+        cmd.error(clap::error::ErrorKind::Io, format!("{}", e))
+            .exit();
+    }
 }

roapi/src/startup.rs

@@ -19,6 +19,8 @@ pub enum Error {
     BuildHttpServer { source: server::http::Error },
     #[snafu(display("Failed to build FlightSQL server: {source}"))]
     BuildFlightSqlServer { source: server::flight_sql::Error },
+    #[snafu(display("Failed to build context: {source}"))]
+    BuildContext { source: crate::context::Error },
 }
 
 // TODO: replace table reloader with the new concurrent refresh infra
@@ -61,7 +63,7 @@ impl Application {
 
         let handler_ctx = RawRoapiContext::new(&config, !config.disable_read_only)
             .await
-            .expect("Failed to create Roapi context");
+            .context(BuildContextSnafu)?;
 
         let tables = config
             .tables