Replace variable expression ${} in environment properties file

Author: harawata

src/main/java/org/apache/ibatis/migration/Environment.java

@@ -27,6 +27,8 @@
 import java.util.Map;
 import java.util.Properties;
 
+import org.apache.ibatis.parsing.GenericTokenParser;
+
 public class Environment {
 
   public static final String CHANGELOG = "changelog";
@@ -102,6 +104,17 @@ private enum SETTING_KEY {
   private final Properties sysProps = System.getProperties();
   private final Properties variables = new Properties();
 
+  private final GenericTokenParser parser = new GenericTokenParser("${", "}", key -> {
+    String value = sysProps.getProperty(key);
+    if (value == null) {
+      value = envVars.get(key);
+    }
+    if (value == null) {
+      value = "${" + key + "}";
+    }
+    return value;
+  });
+
   public Environment(File file) {
     try (FileInputStream inputStream = new FileInputStream(file)) {
       Properties prop = new Properties();
@@ -136,7 +149,7 @@ public Environment(File file) {
 
       // User defined variables.
       prop.entrySet().stream().filter(e -> !SETTING_KEYS.contains(e.getKey())).forEach(e -> {
-        variables.put(e.getKey(), e.getValue());
+        variables.put(e.getKey(), parser.parse((String) e.getValue()));
       });
     } catch (FileNotFoundException e) {
       throw new MigrationException("Environment file missing: " + file.getAbsolutePath());
@@ -162,7 +175,7 @@ protected String readProperty(Properties properties, String propertyKey, String
     }
     // 3. Read .properties file with variable replacement.
     property = properties.getProperty(propertyKey, defaultValue);
-    return property == null ? null : property;
+    return property == null ? null : parser.parse(property);
   }
 
   public String getTimeZone() {

src/test/java/org/apache/ibatis/migration/system_property/SystemPropertyTest.java

@@ -56,11 +56,16 @@ public void checkAssertion() {
 
     // Set system properties
     System.setProperty("MIGRATIONS_DRIVER", "org.hsqldb.jdbcDriver");
+    System.setProperty("username", "Pocahontas");
+    System.setProperty("var1", "Variable 1");
 
     Migrator.main(TestUtil.args("--path=" + dir.getAbsolutePath(), "up", "1", "--trace"));
 
     String output = out.getLog();
     assertTrue(output.contains("SUCCESS"));
+    assertTrue(output.contains("username: Pocahontas"));
+    assertTrue(output.contains("var1: Variable 1"));
+    assertTrue(output.contains("var2: ${var2}"));
 
     out.clearLog();
     System.exit(0);

src/test/java/org/apache/ibatis/migration/system_property/testdir/environments/development.properties

@@ -16,7 +16,10 @@
 
 driver=should_be_overwritten_by_system_property
 url=jdbc:hsqldb:mem:sysprop
-username=Pocahontas
+username=${username}
 password=
 
 changelog=CHANGELOG
+
+var1=${var1}
+var2=${var2}

src/test/java/org/apache/ibatis/migration/system_property/testdir/scripts/001_create_changelog.sql

@@ -35,6 +35,10 @@ ALTER TABLE ${changelog}
 ADD CONSTRAINT PK_${changelog}
 PRIMARY KEY (id);
 
+SELECT 'username: ' || USER_NAME FROM INFORMATION_SCHEMA.SYSTEM_USERS;
+SELECT 'var1: ' || '${var1}' FROM (VALUES(0));
+SELECT 'var2: ' || '${var2}' FROM (VALUES(0));
+
 
 -- //@UNDO