Improve DSN env vairable expansion (#92)

* Improve DSN env vairable expansion

* Add failing test case.

* improve query param handling

* add new config syntax

---------

Co-authored-by: Geoff Greer <geoff@greer.fm>

Author: pquerna

examples/example.yml

@@ -10,17 +10,27 @@ app_name: Example Application
 # Connection Configuration
 # ----------------------
 # Specifies how to connect to the data source. Supports various connection methods.
+# 
+# RECOMMENDED: Use structured fields!
 connect:
-  # Database connection string (DSN) with environment variable interpolation
-  dsn: "mysql://${DB_USER}:${DB_PASS}@${DB_HOST}:3306/${DB_NAME}?parseTime=true"
-# If your database username or password includes characters that require URL encoding,
-# you can specify them as separate options instead of embedding them directly in the DSN.
-# Environment variables are expanded.
-# For example, you might include:
-#   username: my_username
-#   password: my_secure_password
+  scheme: "mysql"
+  host: "${DB_HOST}"
+  port: "3306"
+  database: "${DB_NAME}"
+  user: "${DB_USER}"
+  password: "${DB_PASS}"
+  params:
+    parseTime: "true"
 #
-# This allows the connector to handle proper URL encoding during DSN construction.
+# ALTERNATIVE: Use DSN with separate user/password fields
+# connect:
+#   dsn: "mysql://${DB_HOST}:3306/${DB_NAME}?parseTime=true"
+#   user: "${DB_USER}"
+#   password: "${DB_PASS}"
+#
+# LEGACY: Complete DSN (not recommended if credentials contain special characters)
+# connect:
+#   dsn: "mysql://${DB_USER}:${DB_PASS}@${DB_HOST}:3306/${DB_NAME}?parseTime=true"
 
 # Resource Types
 # -------------

pkg/bsql/config.go

@@ -36,18 +36,36 @@ func (c Config) HasActions() bool {
 }
 
 // DatabaseConfig contains settings required to connect to the database.
+// You can specify either a complete DSN, or use structured fields, or a combination.
+// Structured fields override corresponding parts of the DSN when both are provided.
 type DatabaseConfig struct {
-	// DSN is the Database Source Name connection string used to establish the database connection.
+	// DSN is the Database Source Name connection string (optional if using structured fields).
+	// Supports environment variable expansion via ${VAR_NAME} syntax.
+	// Example: "postgres://${DB_HOST}:${DB_PORT}/${DB_DATABASE}?sslmode=disable"
 	DSN string `yaml:"dsn" json:"dsn"`
 
-	// These fields are not required if the DSN already includes the credentials.
-	// They should only be provided if the username or password contain characters that need URL encoding.
+	// Structured connection fields (optional, override DSN components when set)
 
-	// User is the database username used for authentication.
+	// Scheme is the database type (e.g., "postgres", "mysql", "sqlserver", "oracle", "hdb")
+	Scheme string `yaml:"scheme" json:"scheme"`
+
+	// Host is the database server hostname or IP address (may include port for some databases)
+	Host string `yaml:"host" json:"host"`
+
+	// Port is the database server port number
+	Port string `yaml:"port" json:"port"`
+
+	// Database is the name of the database to connect to
+	Database string `yaml:"database" json:"database"`
+
+	// User is the database username used for authentication
 	User string `yaml:"user" json:"user"`
 
-	// Password is the database password used for authentication.
+	// Password is the database password used for authentication
 	Password string `yaml:"password" json:"password"`
+
+	// Params contains additional connection parameters (e.g., {"sslmode": "disable", "timeout": "30s"})
+	Params map[string]string `yaml:"params" json:"params"`
 }
 
 // ResourceType defines configuration for a specific type of resource.

pkg/connector/connector.go

@@ -94,7 +94,18 @@ func New(ctx context.Context, configFilePath string) (*Connector, error) {
 }
 
 func newConnector(ctx context.Context, c *bsql.Config) (*Connector, error) {
-	db, dbEngine, err := database.Connect(ctx, c.Connect.DSN, c.Connect.User, c.Connect.Password)
+	opts := database.ConnectOptions{
+		DSN:      c.Connect.DSN,
+		Scheme:   c.Connect.Scheme,
+		Host:     c.Connect.Host,
+		Port:     c.Connect.Port,
+		Database: c.Connect.Database,
+		User:     c.Connect.User,
+		Password: c.Connect.Password,
+		Params:   c.Connect.Params,
+	}
+
+	db, dbEngine, err := database.Connect(ctx, opts)
 	if err != nil {
 		return nil, err
 	}