Merge pull request #13 from DarkKirb/env-config

Add support for reading database url from environment variable

nixos/atticd.nix

@@ -17,6 +17,7 @@ let
     cat $configFile
 
     export ATTIC_SERVER_TOKEN_HS256_SECRET_BASE64="dGVzdCBzZWNyZXQ="
+    export ATTIC_SERVER_DATABASE_URL="sqlite://:memory:"
     ${cfg.package}/bin/atticd --mode check-config -f $configFile
     cat <$configFile >$out
   '';
@@ -36,7 +37,7 @@ let
   '';
 
   hasLocalPostgresDB = let
-    url = cfg.settings.database.url;
+    url = cfg.settings.database.url or "";
     localStrings = [ "localhost" "127.0.0.1" "/run/postgresql" ];
     hasLocalStrings = lib.any (lib.flip lib.hasInfix url) localStrings;
   in config.services.postgresql.enable && lib.hasPrefix "postgresql://" url && hasLocalStrings;

server/src/config.rs

@@ -28,6 +28,9 @@ const ENV_CONFIG_BASE64: &str = "ATTIC_SERVER_CONFIG_BASE64";
 /// Environment variable storing the Base64-encoded HS256 JWT secret.
 const ENV_TOKEN_HS256_SECRET_BASE64: &str = "ATTIC_SERVER_TOKEN_HS256_SECRET_BASE64";
 
+/// Environment variable storing the database connection string.
+const ENV_DATABASE_URL: &str = "ATTIC_SERVER_DATABASE_URL";
+
 /// Configuration for the Attic Server.
 #[derive(Clone, Derivative, Deserialize)]
 #[derivative(Debug)]
@@ -118,6 +121,7 @@ pub struct Config {
 #[derive(Debug, Clone, Deserialize)]
 pub struct DatabaseConfig {
     /// Connection URL.
+    #[serde(default = "load_database_url_from_env")]
     pub url: String,
 
     /// Whether to enable sending of periodic heartbeat queries.
@@ -242,6 +246,11 @@ fn load_token_hs256_secret_from_env() -> HS256Key {
     decode_token_hs256_secret_base64(&s).expect("Failed to load as decoding key")
 }
 
+fn load_database_url_from_env() -> String {
+    env::var(ENV_DATABASE_URL)
+        .expect("Database URL must be specified in either database.url or the ATTIC_SERVER_DATABASE_URL environment.")
+}
+
 impl CompressionConfig {
     pub fn level(&self) -> CompressionLevel {
         if let Some(level) = self.level {