make .env a mandatory arg

Cargo.lock

@@ -36,6 +36,12 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0942ffc6dcaadf03badf6e6a2d0228460359d5e34b57ccdc720b7382dfbd5ec5"
 
+[[package]]
+name = "anstyle"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8901269c6307e8d93993578286ac0edf7f195079ffff5ebdeea6a59ffb7e36bc"
+
 [[package]]
 name = "askama"
 version = "0.12.1"
@@ -264,6 +270,46 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "clap"
+version = "4.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b230ab84b0ffdf890d5a10abdbc8b83ae1c4918275daea1ab8801f71536b2651"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae129e2e766ae0ec03484e609954119f123cc1fe650337e155d03b022f24f7b4"
+dependencies = [
+ "anstyle",
+ "clap_lex",
+ "unicase",
+ "unicode-width",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "307bc0538d5f0f83b8248db3087aa92fe504e4691294d0c96c0eabc33f47ba47"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.52",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
+
 [[package]]
 name = "const-oid"
 version = "0.9.6"
@@ -1126,6 +1172,7 @@ dependencies = [
  "askama_axum",
  "axum",
  "chrono",
+ "clap",
  "dotenvy",
  "env_logger",
  "justerror",
@@ -1936,6 +1983,12 @@ version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4c87d22b6e3f4a18d4d40ef354e97c90fcb14dd91d7dc0aa9d8a1172ebf7202"
 
+[[package]]
+name = "unicode-width"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e51733f11c9c4f72aa0c160008246859e340b00807569a0da0e7a1079b27ba85"
+
 [[package]]
 name = "unicode_categories"
 version = "0.1.1"

Cargo.toml

@@ -8,6 +8,7 @@ askama = { version = "0.12", default-features = false, features = ["with-axum",
 askama_axum = { version = "0.4", default-features = false }
 axum = { version = "0.7", default-features = false, features = ["tokio", "http1", "form"] }
 chrono = { version = "0.4", default-features = false, features = ["now"] }
+clap = { version = "4", default-features = false, features = ["derive", "unicode", "help", "usage", "std"] }
 dotenvy = { version = "0.15", default-features = false }
 env_logger = { version = "0.11", default-features = false, features = ["humantime"] }
 justerror = { version = "1" }

src/main.rs

@@ -1,5 +1,6 @@
 use std::{
     env::VarError,
+    ffi::OsString,
     io::Write,
     net::{Ipv4Addr, SocketAddr},
 };
@@ -8,6 +9,7 @@ use axum::{
     routing::{get, MethodRouter},
     Router,
 };
+use clap::Parser;
 use sqlx::sqlite::{SqliteConnectOptions, SqlitePool, SqlitePoolOptions};
 use tokio::net::TcpListener;
 use tower_http::services::ServeDir;
@@ -56,8 +58,15 @@ async fn main() {
 //-************************************************************************
 // li'l helpers
 //-************************************************************************
+#[derive(Debug, Parser)]
+struct Cli {
+    #[clap(long, short)]
+    pub env: OsString,
+}
+
 fn init() {
-    dotenvy::dotenv().expect("Could not read .env file.");
+    let cli = Cli::parse();
+    dotenvy::from_path_override(cli.env).expect("Could not read .env file.");
     env_logger::builder()
         .format(|buf, record| {
             let ts = buf.timestamp();