Improve config loading message (#933)

* Improve config load message

* Raised log level to error. Log link to config example in the guide.

* Changelog

Co-authored-by: Adi Seredinschi <adi@informal.systems>

CHANGELOG.md

@@ -13,6 +13,9 @@
 - [ibc]
   - Started `unwrap` cleanup ([#871])
 
+- [ibc-relayer-cli]
+  - Improve config loading message ([#996])
+
 ### BUG FIXES
 
 - [ibc-relayer]
@@ -28,6 +31,7 @@
 [#911]: https://github.com/informalsystems/ibc-rs/issues/911
 [#972]: https://github.com/informalsystems/ibc-rs/issues/972
 [#983]: https://github.com/informalsystems/ibc-rs/issues/983
+[#996]: https://github.com/informalsystems/ibc-rs/issues/996
 
 ## v0.3.2
 *May 21st, 2021*

relayer-cli/src/commands.rs

@@ -10,7 +10,7 @@ use std::path::PathBuf;
 use abscissa_core::{
     config::Override, Command, Configurable, FrameworkError, Help, Options, Runnable,
 };
-use tracing::info;
+use tracing::{error, info};
 
 use crate::config::Config;
 use crate::DEFAULT_CONFIG_PATH;
@@ -35,7 +35,6 @@ mod version;
 
 /// Default configuration file path
 pub fn default_config_file() -> Option<PathBuf> {
-    info!("Using default configuration from: '.hermes/config.toml'");
     dirs_next::home_dir().map(|home| home.join(DEFAULT_CONFIG_PATH))
 }
 
@@ -96,9 +95,32 @@ pub enum CliCmd {
 /// This trait allows you to define how application configuration is loaded.
 impl Configurable<Config> for CliCmd {
     /// Location of the configuration file
+    /// This is called only when the `-c` command-line option is omitted.
     fn config_path(&self) -> Option<PathBuf> {
-        let filename = default_config_file();
-        filename.filter(|f| f.exists())
+        let path = default_config_file();
+
+        match path {
+            Some(path) if path.exists() => {
+                info!("using default configuration from '{}'", path.display());
+                Some(path)
+            }
+            Some(path) => {
+                // No file exists at the config path
+                error!("could not find configuration file at '{}'", path.display());
+                error!("for an example, please see https://hermes.informal.systems/config.html#example-configuration-file");
+                None
+            }
+            None => {
+                // The path to the default config file could not be found
+                error!("could not find default configuration file");
+                error!(
+                    "please create one at '~/{}' or specify it with the '-c'/'--config' flag",
+                    DEFAULT_CONFIG_PATH
+                );
+                error!("for an example, please see https://hermes.informal.systems/config.html#example-configuration-file");
+                None
+            }
+        }
     }
 
     /// Apply changes to the config after it's been loaded, e.g. overriding

relayer-cli/src/lib.rs

@@ -32,5 +32,5 @@ pub(crate) mod components;
 pub(crate) mod conclude;
 pub(crate) mod entry;
 
-/// The path to the default configuration file.
+/// The path to the default configuration file, relative to the home directory.
 pub const DEFAULT_CONFIG_PATH: &str = ".hermes/config.toml";