Load environment variables optionally from .env

This is most helpful for local testing 😸

.gitignore

@@ -1,2 +1,3 @@
 /target
 *.swp
+.env

Cargo.lock

@@ -390,6 +390,7 @@ dependencies = [
  "aws_lambda_events",
  "clap 2.33.3",
  "deltalake",
+ "dotenv",
  "lambda_runtime",
  "log",
  "parquet",
@@ -475,6 +476,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "212d0f5754cb6769937f4501cc0e67f4f4483c8d2c3e1e922ee9edbe4ab4c7c0"
 
+[[package]]
+name = "dotenv"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77c90badedccf4105eca100756a0b1289e191f6fcbdadd3cee1d2f614f97da8f"
+
 [[package]]
 name = "dtoa"
 version = "0.4.8"

Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 arrow  = "4"
 clap = "2"
 deltalake = { git = "https://github.com/rtyler/delta-rs", branch = "mixing-in-deltalake_ext", features = ["s3"] }
+dotenv = "0.15"
 log = "0.4"
 parquet = "4"
 pretty_env_logger = "0.4"

src/main.rs

@@ -12,6 +12,8 @@ fn preboot() {
     #[cfg(debug_assertions)]
     pretty_env_logger::init();
 
+    dotenv::dotenv().ok();
+
     info!(
         "Initializing delta-s3-loader v{}",
         env!["CARGO_PKG_VERSION"]