use schema name as db username

service/src/main/kotlin/vdi/conf/DatabaseConfigurationMap.kt

@@ -9,7 +9,6 @@ import org.veupathdb.vdi.lib.common.field.SecretString
 private const val DB_ENABLED_PREFIX = EnvKey.AppDB.DBEnabledPrefix
 private const val DB_NAME_PREFIX    = EnvKey.AppDB.DBNamePrefix
 private const val DB_LDAP_PREFIX    = EnvKey.AppDB.DBLDAPPrefix
-private const val DB_USER_PREFIX    = EnvKey.AppDB.DBUserPrefix
 private const val DB_PASS_PREFIX    = EnvKey.AppDB.DBPassPrefix
 private const val DB_SCHEMA_PREFIX  = EnvKey.AppDB.DBDataSchemaPrefix
 
@@ -27,11 +26,7 @@ private const val DB_ENV_VAR_INIT_CAPACITY = 12
 class DatabaseConfigurationMap(environment: Environment)
 : Map<String, DatabaseConfiguration>
 {
-  private val raw: Map<String, DatabaseConfiguration>
-
-  init {
-    raw = parseDatabaseConfigs(environment)
-  }
+  private val raw: Map<String, DatabaseConfiguration> = parseDatabaseConfigs(environment)
 
   override val entries: Set<Map.Entry<String, DatabaseConfiguration>>
     get() = raw.entries
@@ -54,21 +49,29 @@ class DatabaseConfigurationMap(environment: Environment)
   override fun containsKey(key: String) = raw.containsKey(key)
 }
 
-
 private fun parseDatabaseConfigs(environment: Environment) =
   environment.parse()
 
 private fun Environment.parse(): Map<String, DatabaseConfiguration> {
   val out  = HashMap<String, DatabaseConfiguration>(DB_ENV_VAR_INIT_CAPACITY)
   val seen = HashSet<String>(12)
 
+  // Iterate through all the environment variables available to the server
+  // process looking for variables that start with one of the known prefixes.
+  //
+  // When a matching variable is found it will be passed to the `parse` method
+  // which will attempt to build a full `DatabaseConfiguration` instance by
+  // requiring the remaining variables for that config set exist in the
+  // environment.
+  //
+  // `parse` will also update the `seen` set with the config set key to avoid
+  // processing the same config set multiple times.
   forEach { (key, _) ->
     when {
       key.startsWith(DB_ENABLED_PREFIX) -> parse(key.substring(DB_ENABLED_PREFIX.length), seen, out)
       key.startsWith(DB_SCHEMA_PREFIX)  -> parse(key.substring(DB_SCHEMA_PREFIX.length), seen, out)
       key.startsWith(DB_NAME_PREFIX)    -> parse(key.substring(DB_NAME_PREFIX.length), seen, out)
       key.startsWith(DB_LDAP_PREFIX)    -> parse(key.substring(DB_LDAP_PREFIX.length), seen, out)
-      key.startsWith(DB_USER_PREFIX)    -> parse(key.substring(DB_USER_PREFIX.length), seen, out)
       key.startsWith(DB_PASS_PREFIX)    -> parse(key.substring(DB_PASS_PREFIX.length), seen, out)
     }
   }
@@ -77,16 +80,27 @@ private fun Environment.parse(): Map<String, DatabaseConfiguration> {
 }
 
 private fun Environment.parse(key: String, names: MutableSet<String>, out: MutableMap<String, DatabaseConfiguration>) {
+  // If a database config set with the given key has already been seen (present
+  // in the names set) then skip it because we've already processed this config
+  // set.
   if (key in names)
     return
 
+  // Add the key to the seen config set names set.
+  names.add(key)
+
+  // Build the DatabaseConfiguration instance from the environment.
+  //
+  // If the enabled flag for the database config set is `false`, then skip the
+  // config set.
   if (reqBool(DB_ENABLED_PREFIX + key)) {
     val name = require(DB_NAME_PREFIX + key)
 
     out[name] = DatabaseConfiguration(
       name       = name,
       ldap       = require(DB_LDAP_PREFIX + key),
-      user       = require(DB_USER_PREFIX + key),
+      // We now use the DB schema as the username.
+      user       = require(DB_SCHEMA_PREFIX + key),
       pass       = SecretString(require(DB_PASS_PREFIX + key)),
       dataSchema = require(DB_SCHEMA_PREFIX + key),
     )