Add cli parsing logic and logging to rotom_discord_bot

.env.example

@@ -0,0 +1,20 @@
+# Logging (env_logger) -----------------------------------------------------------------------------------
+
+RUST_LOG="rotom_discord_bot=debug"
+
+# Discord ------------------------------------------------------------------------------------------------
+
+BOT_TOKEN="my_bot_token"
+
+# Database -----------------------------------------------------------------------------------------------
+
+# DATABASE_DIALECT="mysql"
+# DATABASE_URL="mysql://username:password@host/database"
+
+# DATABASE_DIALECT="postgres"
+# DATABASE_URL="postgres://username:password@host/database"
+
+DATABASE_DIALECT="sqlite"
+DATABASE_URL="/path/to/sqlite/database.db"
+
+# --------------------------------------------------------------------------------------------------------

Cargo.lock

@@ -32,6 +32,56 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
+[[package]]
+name = "anstream"
+version = "0.6.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8acc5369981196006228e28809f761875c0327210a891e941f4c683b3a99529b"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is_terminal_polyfill",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55cc3b69f167a1ef2e161439aa98aed94e6028e5f9a59be9a6ffb47aef1651f9"
+
+[[package]]
+name = "anstyle-parse"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b2d16507662817a6a20a9ea92df6652ee4f94f914589377d69f3b21bc5798a9"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79947af37f4177cfead1110013d678905c37501914fba0efea834c3fe9a8d60c"
+dependencies = [
+ "windows-sys 0.59.0",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3534e77181a9cc07539ad51f2141fe32f6c3ffd4df76db8ad92346b003ae4e"
+dependencies = [
+ "anstyle",
+ "once_cell",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "async-trait"
 version = "0.1.85"
@@ -43,6 +93,17 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -94,7 +155,7 @@ version = "0.71.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f58bf3d7db68cfbac37cfc485a8d711e87e064c3d0fe0435b92f7a407f9d6b3"
 dependencies = [
- "bitflags",
+ "bitflags 2.8.0",
  "cexpr",
  "clang-sys",
  "itertools",
@@ -106,6 +167,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.8.0"
@@ -185,6 +252,70 @@ dependencies = [
  "libloading",
 ]
 
+[[package]]
+name = "clap"
+version = "3.2.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ea181bf566f71cb9a5d17a59e1871af638180a18fb0035c92ae62b705207123"
+dependencies = [
+ "atty",
+ "bitflags 1.3.2",
+ "clap_lex 0.2.4",
+ "indexmap 1.9.3",
+ "strsim 0.10.0",
+ "termcolor",
+ "textwrap",
+]
+
+[[package]]
+name = "clap"
+version = "4.5.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "769b0145982b4b48713e01ec42d61614425f27b7058bda7180a3a41f30104796"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.5.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b26884eb4b57140e4d2d93652abfa49498b938b3c9179f9fc487b0acc3edad7"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "clap_lex 0.7.4",
+ "strsim 0.11.1",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.5.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54b755194d6389280185988721fffba69495eed5ee9feeee9a599b53db80318c"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2850f2f5a82cbf437dd5af4d49848fbdfc27c157c3d010345776f952765261c5"
+dependencies = [
+ "os_str_bytes",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f46ad14479a25103f283c0f10005961cf086d8dc42205bb44c46ac563475dca6"
+
 [[package]]
 name = "cmake"
 version = "0.1.52"
@@ -194,6 +325,12 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "colorchoice"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.16"
@@ -298,7 +435,7 @@ dependencies = [
  "ident_case",
  "proc-macro2",
  "quote",
- "strsim",
+ "strsim 0.11.1",
  "syn",
 ]
 
@@ -328,7 +465,7 @@ version = "2.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf1bedf64cdb9643204a36dd15b19a6ce8e7aa7f7b105868e9f1fad5ffa7d12"
 dependencies = [
- "bitflags",
+ "bitflags 2.8.0",
  "byteorder",
  "diesel_derives",
  "itoa",
@@ -413,6 +550,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "dotenvy"
+version = "0.15.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1aaf95b3e5c8f23aa320147307562d361db0ae0d51242340f558153b4eb2439b"
+dependencies = [
+ "clap 3.2.25",
+]
+
 [[package]]
 name = "dsl_auto_type"
 version = "0.1.2"
@@ -433,6 +579,29 @@ version = "1.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
 
+[[package]]
+name = "env_filter"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "186e05a59d4c50738528153b83b0b0194d3a29507dfec16eccd4b342903397d0"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.11.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcaee3d8e3cfc3fd92428d477bc97fc29ec8716d180c0d74c643bb26166660e0"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "env_filter",
+ "humantime",
+ "log",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -563,6 +732,12 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8d1add55171497b4705a648c6b583acafb01d58050a51727785f0b2c8e0a2b2"
 
+[[package]]
+name = "hashbrown"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
+
 [[package]]
 name = "hashbrown"
 version = "0.15.2"
@@ -580,6 +755,15 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hmac"
 version = "0.12.1"
@@ -589,6 +773,12 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "humantime"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
+
 [[package]]
 name = "icu_collections"
 version = "1.5.0"
@@ -734,6 +924,16 @@ dependencies = [
  "icu_properties",
 ]
 
+[[package]]
+name = "indexmap"
+version = "1.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd070e393353796e801d209ad339e89596eb4c8d430d18ede6a1cced8fafbd99"
+dependencies = [
+ "autocfg",
+ "hashbrown 0.12.3",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.7.1"
@@ -741,9 +941,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8c9c992b02b5b4c94ea26e32fe5bccb7aa7d9f390ab5c1221ff895bc7ea8b652"
 dependencies = [
  "equivalent",
- "hashbrown",
+ "hashbrown 0.15.2",
 ]
 
+[[package]]
+name = "is_terminal_polyfill"
+version = "1.70.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
+
 [[package]]
 name = "itertools"
 version = "0.13.0"
@@ -784,7 +990,7 @@ version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ee7893dab2e44ae5f9d0173f26ff4aa327c10b01b06a72b52dd9405b628640d"
 dependencies = [
- "indexmap",
+ "indexmap 2.7.1",
 ]
 
 [[package]]
@@ -847,7 +1053,7 @@ version = "0.12.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "234cf4f4a04dc1f57e24b96cc0cd600cf2af460d4161ac5ecdd0af8e1f3b2a38"
 dependencies = [
- "hashbrown",
+ "hashbrown 0.15.2",
 ]
 
 [[package]]
@@ -910,7 +1116,7 @@ checksum = "2886843bf800fba2e3377cff24abf6379b4c4d5c6681eaf9ea5b0d15090450bd"
 dependencies = [
  "libc",
  "wasi",
- "windows-sys",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -950,7 +1156,7 @@ checksum = "478b0ff3f7d67b79da2b96f56f334431aef65e15ba4b29dd74a4236e29582bdc"
 dependencies = [
  "base64 0.21.7",
  "bindgen",
- "bitflags",
+ "bitflags 2.8.0",
  "btoi",
  "byteorder",
  "bytes",
@@ -1044,6 +1250,12 @@ version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
+[[package]]
+name = "os_str_bytes"
+version = "6.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2355d85b9a3786f481747ced0e0ff2ba35213a1f9bd406ed906554d7af805a1"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.3"
@@ -1246,7 +1458,7 @@ version = "0.5.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "03a862b389f93e68874fbf580b9de08dd02facb9a788ebadaf4a3fd33cf58834"
 dependencies = [
- "bitflags",
+ "bitflags 2.8.0",
 ]
 
 [[package]]
@@ -1301,8 +1513,15 @@ dependencies = [
 name = "rotom_discord_bot"
 version = "0.1.0"
 dependencies = [
+ "clap 4.5.27",
+ "dotenvy",
+ "env_logger",
+ "log",
  "rotom_core",
  "rotom_database",
+ "secrecy",
+ "thiserror 2.0.11",
+ "tokio",
 ]
 
 [[package]]
@@ -1344,6 +1563,15 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "secrecy"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e891af845473308773346dc847b2c23ee78fe442e0472ac50e22a18a93d3ae5a"
+dependencies = [
+ "zeroize",
+]
+
 [[package]]
 name = "serde"
 version = "1.0.217"
@@ -1413,6 +1641,15 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9e9e0b4211b72e7b8b6e85c807d36c212bdb33ea8587f7569562a84df5465b1"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "siphasher"
 version = "1.0.1"
@@ -1441,7 +1678,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c970269d99b64e60ec3bd6ad27270092a5394c4e309314b18ae3fe575695fbe8"
 dependencies = [
  "libc",
- "windows-sys",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -1467,6 +1704,12 @@ dependencies = [
  "unicode-properties",
 ]
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "strsim"
 version = "0.11.1"
@@ -1511,6 +1754,21 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06794f8f6c5c898b3275aebefa6b8a1cb24cd2c6c79397ab15774837a0bc5755"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "textwrap"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23d434d3f8967a09480fb04132ebe0a3e088c173e6d0ee7897abbdf4eab0f8b9"
+
 [[package]]
 name = "thiserror"
 version = "1.0.69"
@@ -1619,8 +1877,21 @@ dependencies = [
  "mio",
  "parking_lot",
  "pin-project-lite",
+ "signal-hook-registry",
  "socket2",
- "windows-sys",
+ "tokio-macros",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e06d43f1345a3bcd39f6a56dbb7dcab2ba47e68e8ac134855e7e2bdbaf8cab8"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -1689,7 +1960,7 @@ version = "0.22.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ae48d6208a266e853d946088ed816055e556cc6028c5e8e2b84d9fa5dd7c7f5"
 dependencies = [
- "indexmap",
+ "indexmap 2.7.1",
  "serde",
  "serde_spanned",
  "toml_datetime",
@@ -1763,6 +2034,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
 [[package]]
 name = "uuid"
 version = "1.12.0"
@@ -1887,6 +2164,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
+dependencies = [
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
@@ -1902,6 +2188,15 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.59.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+dependencies = [
+ "windows-targets",
+]
+
 [[package]]
 name = "windows-targets"
 version = "0.52.6"
@@ -2053,6 +2348,12 @@ dependencies = [
  "synstructure",
 ]
 
+[[package]]
+name = "zeroize"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ced3678a2879b30306d323f4542626697a464a97c0a07c9aebf7ebca65cd4dde"
+
 [[package]]
 name = "zerovec"
 version = "0.10.4"

rotom_discord_bot/Cargo.toml

@@ -4,8 +4,15 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+clap = { version = "4.5.27", features = ["derive", "env"] }
+dotenvy = { version = "0.15.7", features = ["clap"] }
+env_logger = "0.11.6"
+log = "0.4.25"
 rotom_core = { path = "../rotom_core" }
 rotom_database = { path = "../rotom_database", default-features = false }
+secrecy = "0.10.3"
+thiserror = "2.0.11"
+tokio = { version = "1.43.0", features = ["full"] }
 
 [features]
 default = ["mysql", "postgres", "sqlite"]

rotom_discord_bot/src/app/mod.rs

@@ -0,0 +1,17 @@
+use rotom_core::repository::RepositoryProvider;
+
+use crate::cli::DiscordCredentials;
+
+#[derive(Debug, thiserror::Error)]
+pub enum AppError {
+
+}
+
+pub async fn start<R>(_credentials: DiscordCredentials, _repository_provider: R) -> Result<(), AppError>
+where
+    R: RepositoryProvider + Send + Sync + 'static,
+    R::BackendError: Send + Sync,
+    for<'a> R::Repository<'a>: Send + Sync,
+{
+    todo!()
+}

rotom_discord_bot/src/cli/command.rs

@@ -0,0 +1,29 @@
+use clap::Parser;
+
+/// Subcommand of the CLI application.
+#[derive(Debug, Clone, Parser)]
+pub enum Command {
+    /// Start the main discord bot application.
+    #[command(
+        name = "start",
+        about,
+        long_about = None,
+    )]
+    Start(super::start::Start),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum CommandError {
+    #[error(transparent)]
+    StartError(#[from] super::start::StartError),
+}
+
+impl Command {
+    pub async fn execute(self) -> Result<(), CommandError> {
+        match self {
+            Command::Start(start) => start.execute().await?,
+        }
+
+        Ok(())
+    }
+}

rotom_discord_bot/src/cli/mod.rs

@@ -0,0 +1,148 @@
+use std::fmt::Debug;
+use std::path::PathBuf;
+
+use clap::Parser;
+use clap::ValueEnum;
+use command::Command;
+use secrecy::SecretString;
+
+pub mod command;
+pub mod start;
+
+#[derive(Debug, thiserror::Error)]
+pub enum CliError {
+    #[error(transparent)]
+    Dotenvy(#[from] dotenvy::Error),
+}
+
+/// Parses command line arguments.
+pub fn parse() -> Result<Cli, CliError> {
+    // First phase: If a dotenv file is specified, load values from it.
+    // This allows values in the dotenv file to be used when parsing other arguments.
+    let dotenv = Dotenv::parse();
+    if let Some(dotenv_path) = &dotenv.path {
+        dotenvy::from_path_override(dotenv_path)?;
+    }
+
+    // Second phase: Parse CLI options using the `Cli` parser.
+    let mut cli = Cli::parse();
+
+    // The `Cli` parser contains the `Dotenv` parser and it may parse different results in different phases.
+    // It is replaced here to ensure the `Cli` instance reflects the original dotenv configuration.
+    cli.dotenv = dotenv;
+
+    return Ok(cli);
+}
+
+/// Main command line interface for the librarian application.
+///
+/// This struct combines the dotenv configuration with the subcommands
+/// that the CLI application supports.
+///
+/// The help and version flags and subcommands are explicitly enabled
+/// because `Dotenv` disables them and `Cli` requires them to be enabled.
+#[derive(Debug, Parser)]
+#[command(
+    name = "rotom",
+    about,
+    version,
+    long_about = None,
+    ignore_errors = false,
+    disable_help_flag = false,
+    disable_help_subcommand = false,
+    disable_version_flag = false,
+)]
+pub struct Cli {
+    /// Configuration for loading environment variables from a dotenv file.
+    #[command(flatten)]
+    pub dotenv: Dotenv,
+
+    /// The command to be executed as part of the CLI application.
+    #[command(subcommand)]
+    pub command: Command,
+}
+
+/// Configuration for loading environment variables from a dotenv file.
+///
+/// This struct is used to specify the path to a dotenv file from which
+/// environment variables can be loaded. The default value is `.env`.
+///
+/// The help and version flags and subcommands are disabled because
+/// they are handled by `Cli` which is parsed after `Dotenv`.
+#[derive(Debug, Clone, Parser)]
+#[command(
+    ignore_errors = true,
+    disable_help_flag = true,
+    disable_help_subcommand = true,
+    disable_version_flag = true
+)]
+pub struct Dotenv {
+    /// The path to the dotenv file.
+    #[arg(
+        name = "path",
+        short = None,
+        long = "dotenv",
+        env = "DOTENV",
+    )]
+    pub path: Option<PathBuf>,
+}
+
+#[derive(Clone, Copy, Debug, ValueEnum)]
+pub enum DatabaseDialect {
+    #[cfg(feature = "mysql")]
+    Mysql,
+    #[cfg(feature = "postgres")]
+    Postgres,
+    #[cfg(feature = "sqlite")]
+    Sqlite,
+}
+
+impl From<DatabaseDialect> for rotom_database::DatabaseDialect {
+    fn from(value: DatabaseDialect) -> Self {
+        use rotom_database::DatabaseDialect as Dialect;
+        match value {
+            #[cfg(feature = "mysql")]
+            DatabaseDialect::Mysql => Dialect::Mysql,
+            #[cfg(feature = "postgres")]
+            DatabaseDialect::Postgres => Dialect::Postgres,
+            #[cfg(feature = "sqlite")]
+            DatabaseDialect::Sqlite => Dialect::Sqlite,
+        }
+    }
+}
+
+/// Credentials required to establish a database connection.
+#[derive(Clone, Debug, Parser)]
+pub struct DatabaseCredentials {
+    /// The dialect of the database to connect to.
+    #[arg(
+        short = None,
+        long = "database-dialect",
+        env = "DATABASE_DIALECT",
+    )]
+    pub dialect: DatabaseDialect,
+
+    /// The URL of the database to connect to. This should include the
+    /// necessary credentials (username and password) and the database
+    /// name, following the format: `dialect://username:password@host:port/database`.
+    #[arg(
+        short = None,
+        long = "database-url",
+        env = "DATABASE_URL",
+        hide_env_values(true),
+    )]
+    pub url: SecretString,
+}
+
+/// Credentials required to authenticate a bot with Discord.
+#[derive(Clone, Debug, Parser)]
+pub struct DiscordCredentials {
+    /// The token used to authenticate the bot with Discord.
+    #[arg(
+        short = None,
+        long = "bot-token",
+        env = "BOT_TOKEN",
+        hide_env_values(true),
+    )]
+    pub bot_token: SecretString,
+}

rotom_discord_bot/src/cli/start.rs

@@ -0,0 +1,62 @@
+use clap::Parser;
+use secrecy::ExposeSecret;
+
+use super::DatabaseCredentials;
+use super::DiscordCredentials;
+
+/// Start the main discord bot application.
+#[derive(Debug, Clone, Parser)]
+pub struct Start {
+    /// Credentials required to establish a database connection.
+    #[command(flatten)]
+    pub database: DatabaseCredentials,
+
+    /// Credentials required to authenticate a bot with Discord.
+    #[command(flatten)]
+    pub discord: DiscordCredentials,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum StartError {
+    #[error(transparent)]
+    RepositoryBackendError(#[from] rotom_database::BackendError),
+    #[error(transparent)]
+    AppError(#[from] crate::app::AppError),
+}
+
+impl Start {
+    pub async fn execute(self) -> Result<(), StartError> {
+        log::debug!("{:#?}", self);
+
+        let database_url = self.database.url.expose_secret();
+
+        match self.database.dialect {
+            #[cfg(feature = "mysql")]
+            crate::cli::DatabaseDialect::Mysql => {
+                log::info!("Running any pending database migrations.");
+                rotom_database::mysql::run_pending_migrations(database_url)?;
+                let repository_provider = rotom_database::mysql::repository_provider(database_url).await?;
+                log::info!("Starting discord application.");
+                crate::app::start(self.discord, repository_provider).await?;
+            },
+            #[cfg(feature = "postgres")]
+            crate::cli::DatabaseDialect::Postgres => {
+                log::info!("Running any pending database migrations.");
+                rotom_database::postgres::run_pending_migrations(database_url)?;
+                let repository_provider = rotom_database::postgres::repository_provider(database_url).await?;
+                log::info!("Starting discord application.");
+                crate::app::start(self.discord, repository_provider).await?;
+            },
+            #[cfg(feature = "sqlite")]
+            crate::cli::DatabaseDialect::Sqlite => {
+                log::info!("Running any pending database migrations.");
+                rotom_database::sqlite::run_pending_migrations(database_url)?;
+                let repository_provider = rotom_database::sqlite::repository_provider(database_url).await?;
+                log::info!("Starting discord application.");
+                crate::app::start(self.discord, repository_provider).await?;
+            },
+        }
+
+        Ok(())
+    }
+}

rotom_discord_bot/src/main.rs

@@ -1 +1,20 @@
-fn main() {}
+mod app;
+mod cli;
+
+#[derive(Debug, thiserror::Error)]
+enum MainError {
+    #[error(transparent)]
+    CliError(#[from] cli::CliError),
+    #[error(transparent)]
+    CommandError(#[from] cli::command::CommandError)
+}
+
+#[tokio::main]
+async fn main() -> Result<(), MainError> {
+    let c = cli::parse()?;
+    env_logger::init();
+
+    c.command.execute().await?;
+
+    Ok(())
+}