✨ feat(cli): add config file support

- load configuration from a file
- use config crate for config loading
- allow overriding config with environment variables
- set default credential path
- fix error handling for config loading

Cargo.lock

@@ -240,6 +240,19 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
 
+[[package]]
+name = "config"
+version = "0.15.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "180e549344080374f9b32ed41bf3b6b57885ff6a289367b3dbc10eea8acc1918"
+dependencies = [
+ "pathdiff",
+ "serde_core",
+ "serde_json",
+ "toml",
+ "winnow",
+]
+
 [[package]]
 name = "core-foundation"
 version = "0.10.1"
@@ -263,6 +276,7 @@ dependencies = [
  "chrono",
  "clap",
  "clap-verbosity-flag",
+ "config",
  "env_logger",
  "google-gmail1",
  "log",
@@ -1017,6 +1031,12 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d05e27ee213611ffe7d6348b942e8f942b37114c00cc03cec254295a4a17852e"
 
+[[package]]
+name = "pathdiff"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df94ce210e5bc13cb6651479fa48d14f601d9858cfe0467f43ae157023b938d3"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -1964,6 +1984,9 @@ name = "winnow"
 version = "0.7.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "21a0236b59786fed61e2a80582dd500fe61f18b5dca67a4a067d0bc9039339cf"
+dependencies = [
+ "memchr",
+]
 
 [[package]]
 name = "writeable"

Cargo.toml

@@ -24,6 +24,7 @@ include = [
 chrono = "0.4.42"
 clap = { version = "4.5.48", features = ["derive"] }
 clap-verbosity-flag = { version = "3.0.4", features = ["tracing"] }
+config = { version = "0.15.18", default-features = false, features = ["json", "toml"] }
 env_logger = "0.11.8"
 google-gmail1 = "6.0.0"
 log = "0.4.28"

src/cli/main.rs

@@ -4,8 +4,9 @@ mod labels_cli;
 mod messages_cli;
 mod rules_cli;
 
-use cull_gmail::{GmailClient, Result, Rules};
+use config::Config;
-use std::error::Error as stdError;
+use cull_gmail::{GmailClient, Result};
+use std::{env, error::Error as stdError};
 
 use labels_cli::LabelsCli;
 use messages_cli::MessagesCli;
@@ -57,7 +58,10 @@ async fn main() {
 }
 
 async fn run(args: Cli) -> Result<()> {
-    let mut client = GmailClient::new("credential.json").await?;
+    let config = get_config()?;
+
+    let credential = config.get_string("credentials")?;
+    let mut client = GmailClient::new(&credential).await?;
 
     match args.sub_command {
         SubCmds::Message(messages_cli) => messages_cli.run(&mut client).await,
@@ -83,23 +87,19 @@ fn get_logging(level: log::LevelFilter) -> env_logger::Builder {
     builder
 }
 
-fn get_config() -> Result<Rules> {
+fn get_config() -> Result<Config> {
-    // let settings = Config::builder()
+    let home_dir = env::home_dir().unwrap();
-    //     // Add in `./Settings.toml`
+    let path = home_dir.join(".cull-gmail/rules.toml");
-    //     .add_source(config::File::with_name("examples/simple/Settings"))
+    log::trace!("Loading config from {}", path.display());
-    //     // Add in settings from the environment (with a prefix of APP)
-    //     // Eg.. `APP_DEBUG=1 ./target/app` would set the `debug` key
-    //     .add_source(config::Environment::with_prefix("APP"))
-    //     .build()
-    //     .unwrap();
 
-    match Rules::load() {
+    Ok(Config::builder()
-        Ok(c) => Ok(c),
+        .set_default("credentials", "credential.json")?
-        Err(_) => {
+        // Add in `./Settings.toml`
-            log::warn!("Configuration not found, creating default config.");
+        .add_source(config::File::with_name(
-            let rules = Rules::new();
+            path.to_path_buf().to_str().unwrap(),
-            rules.save()?;
+        ))
-            Ok(rules)
+        // Add in settings from the environment (with a prefix of APP)
-        }
+        // Eg.. `APP_DEBUG=1 ./target/app` would set the `debug` key
-    }
+        .add_source(config::Environment::with_prefix("APP"))
+        .build()?)
 }

src/error.rs

@@ -45,4 +45,7 @@ pub enum Error {
     /// Error from toml_de
     #[error(transparent)]
     TomlDe(#[from] toml::de::Error),
+    /// Error from config
+    #[error(transparent)]
+    Config(#[from] config::ConfigError),
 }