Read application properties from env first.

Prioritize environment variables over configuration file properties.
This allows the service to adapt dynamically to different deployment
environments by overriding config file settings with environment-specific
values when available.

Author: G8XSU

app/src/main/java/org/vss/guice/BaseModule.java

@@ -52,38 +52,48 @@ class HikariCPDataSource {
 
   static {
     try (InputStream input = HikariCPDataSource.class.getClassLoader()
-        .getResourceAsStream("hikariJdbc.properties")) {
-      Properties hikariJdbcProperties = new Properties();
-      hikariJdbcProperties.load(input);
+        .getResourceAsStream("application.properties")) {
+      Properties applicationProperties = new Properties();
+      applicationProperties.load(input);
 
-      config.setJdbcUrl(hikariJdbcProperties.getProperty("jdbc.url"));
-      config.setUsername(hikariJdbcProperties.getProperty("jdbc.username"));
-      config.setPassword(hikariJdbcProperties.getProperty("jdbc.password"));
+      config.setJdbcUrl(getEnvOrConfigProperty("vss.jdbc.url", applicationProperties));
+      config.setUsername(getEnvOrConfigProperty("vss.jdbc.username", applicationProperties));
+      config.setPassword(getEnvOrConfigProperty("vss.jdbc.password", applicationProperties));
 
       config.setMaximumPoolSize(
-          Integer.parseInt(hikariJdbcProperties.getProperty("hikaricp.maxPoolSize")));
+          Integer.parseInt(getEnvOrConfigProperty("vss.hikaricp.maxPoolSize", applicationProperties)));
       config.setMinimumIdle(
-          Integer.parseInt(hikariJdbcProperties.getProperty("hikaricp.minimumIdle")));
+          Integer.parseInt(getEnvOrConfigProperty("vss.hikaricp.minimumIdle", applicationProperties)));
       config.setConnectionTimeout(
-          Long.parseLong(hikariJdbcProperties.getProperty("hikaricp.connectionTimeout")));
+          Long.parseLong(getEnvOrConfigProperty("vss.hikaricp.connectionTimeout", applicationProperties)));
       config.setIdleTimeout(
-          Long.parseLong(hikariJdbcProperties.getProperty("hikaricp.idleTimeout")));
+          Long.parseLong(getEnvOrConfigProperty("vss.hikaricp.idleTimeout", applicationProperties)));
       config.setMaxLifetime(
-          Long.parseLong(hikariJdbcProperties.getProperty("hikaricp.maxLifetime")));
+          Long.parseLong(getEnvOrConfigProperty("vss.hikaricp.maxLifetime", applicationProperties)));
 
       config.addDataSourceProperty("cachePrepStmts",
-          hikariJdbcProperties.getProperty("hikaricp.cachePrepStmts"));
+          getEnvOrConfigProperty("vss.hikaricp.cachePrepStmts", applicationProperties));
       config.addDataSourceProperty("prepStmtCacheSize",
-          hikariJdbcProperties.getProperty("hikaricp.prepStmtCacheSize"));
+          getEnvOrConfigProperty("vss.hikaricp.prepStmtCacheSize", applicationProperties));
       config.addDataSourceProperty("prepStmtCacheSqlLimit",
-          hikariJdbcProperties.getProperty("hikaricp.prepStmtCacheSqlLimit"));
+          getEnvOrConfigProperty("vss.hikaricp.prepStmtCacheSqlLimit", applicationProperties));
 
       dataSource = new HikariDataSource(config);
     } catch (IOException e) {
-      throw new RuntimeException("Unable to read hikariJdbcProperties from resources");
+      throw new RuntimeException("Unable to read application.properties from resources");
     }
   }
 
+  // Retrieves the value of a specified property, first checking environment variables,
+  // then falling back to provided configuration properties if the environment variable is not set.
+  private static String getEnvOrConfigProperty(String key, Properties hikariJdbcProperties) {
+    String propertyValue = System.getenv(key);
+    if (StringUtils.isBlank(propertyValue)) {
+      propertyValue = hikariJdbcProperties.getProperty(key);
+    }
+    return propertyValue;
+  }
+
   private HikariCPDataSource() {
   }
 }

app/src/main/resources/application.properties

@@ -0,0 +1,26 @@
+# Application Properties File
+# Contains default application properties, these are meant to be changed according to application needs.
+# Each property can be overridden by setting an environment variable with the same name.
+# For example, to override 'vss.jdbc.url', set an environment variable 'vss.jdbc.url' with the new value.
+
+vss.jdbc.url=jdbc:postgresql://localhost:5432/postgres
+vss.jdbc.username=postgres
+vss.jdbc.password=YOU_MUST_CHANGE_THIS_PASSWORD
+
+# Idle Timeout
+vss.hikaricp.minimumIdle=10
+
+# Set connectionTimeout to 30 secs
+vss.hikaricp.connectionTimeout=30000
+
+# Set idle timeout to 10 minutes
+vss.hikaricp.idleTimeout=600000
+
+# Set Maximum lifetime of a connection to 30minutes
+vss.hikaricp.maxLifetime=1800000
+
+# Performance Optimizations
+vss.hikaricp.maxPoolSize=50
+vss.hikaricp.cachePrepStmts=true
+vss.hikaricp.prepStmtCacheSize=250
+vss.hikaricp.prepStmtCacheSqlLimit=2048