[WFLY-14984] Add support for encrypted expressions in the wildfly-config.xml

src/main/java/org/wildfly/client/config/ConfigurationXMLStreamReader.java

@@ -26,6 +26,8 @@
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
+import java.util.ServiceConfigurationError;
+import java.util.ServiceLoader;
 
 import javax.xml.stream.XMLInputFactory;
 import javax.xml.stream.XMLStreamReader;
@@ -725,13 +727,61 @@ default Expression getExpressionAttributeValue(int index, Expression.Flag... fla
         final String attributeValue = getAttributeValue(index);
         if (attributeValue == null) {
             return null;
+        } else if (attributeValue.startsWith("env.")) {
+            String envVar = System.getenv().get(attributeValue.substring(4));
+
+            if (envVar.contains("ENC:")) {
+                return resolveEncryptedExpression(envVar, flags);
+            } else {
+                return Expression.compile(envVar, flags);
+            }
+        } else if (attributeValue.contains("env") || attributeValue.contains("ENV")) {
+            String envVar = replaceNonAlphanumericByUnderscoresAndMakeUpperCase(attributeValue);
+
+            if (envVar.contains("ENC:")) {
+                return resolveEncryptedExpression(envVar, flags);
+            } else {
+                return Expression.compile(envVar, flags);
+            }
+        } else if (attributeValue.startsWith("prop.")) {
+            String propertyValue = System.getProperty(attributeValue.substring(5));
+
+            if (propertyValue.contains("ENC:")) {
+                return resolveEncryptedExpression(propertyValue, flags);
+            } else {
+                return Expression.compile(propertyValue, flags);
+            }
+        } else if (attributeValue.contains("prop") || attributeValue.contains("PROP")) {
+            String propertyValue = System.getProperty(replaceNonAlphanumericByUnderscoresAndMakeUpperCase(attributeValue));
+
+            if (propertyValue.contains("ENC:")) {
+                return resolveEncryptedExpression(propertyValue, flags);
+            } else {
+                return Expression.compile(propertyValue, flags);
+            }
+        } else if (attributeValue.contains("ENC:")) {
+            return resolveEncryptedExpression(attributeValue, flags);
         } else try {
             return Expression.compile(attributeValue, flags);
         } catch (IllegalArgumentException ex) {
             throw msg.expressionParseException(ex, getAttributeName(index), getLocation());
         }
     }
 
+    default Expression resolveEncryptedExpression(String attributeValue,  Expression.Flag... flags) throws ConfigXMLParseException {
+        try {
+            Iterator<ResolverProvider> resolverProviderIterator = ServiceLoader.load(ResolverProvider.class, ConfigurationXMLStreamReader.class.getClassLoader()).iterator();
+            if (resolverProviderIterator.hasNext()) {
+                final ResolverProvider resolverProvider = resolverProviderIterator.next();
+                return Expression.compile(resolverProvider.resolveExpression(attributeValue), flags);
+            } else {
+                throw msg.failedToLoadResolver();
+            }
+        } catch (ServiceConfigurationError e) {
+            throw msg.failedToLoadUsingServiceLoader(ResolverProvider.class.getName());
+        }
+    }
+
     /**
      * Get an attribute value as a {@link InetAddress}.
      *
@@ -811,4 +861,20 @@ default CidrAddress getCidrAddressAttributeValueResolved(int index) throws Confi
             return cidrAddress;
         }
     }
+
+    default String replaceNonAlphanumericByUnderscoresAndMakeUpperCase(final String name) {
+        StringBuilder sb = new StringBuilder();
+        int c;
+        for (int i = 0; i < name.length(); i += Character.charCount(c)) {
+            c = Character.toUpperCase(name.codePointAt(i));
+            if ('A' <= c && c <= 'Z' || '0' <= c && c <= '9') {
+                sb.appendCodePoint(c);
+            } else if (c == '{' || c == '}' || c == '$') {
+                //ignore these characters
+            }else {
+                sb.append('_');
+            }
+        }
+        return sb.toString();
+    }
 }

src/main/java/org/wildfly/client/config/ResolverProvider.java

@@ -0,0 +1,28 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ * Copyright 2024 Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.wildfly.client.config;
+
+/**
+ * An interface that allows WildFly-Client-Config to use Functions from
+ * Encrypted Expression Resolver without adding an Elytron dependency.
+ * @author <a href="mailto:[email protected]">Prarthona Paul</a>
+ */
+public interface ResolverProvider {
+    String resolveExpression(String expression);
+}

src/main/java/org/wildfly/client/config/_private/ConfigMessages.java

@@ -21,6 +21,7 @@
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URISyntaxException;
+import java.util.ServiceConfigurationError;
 
 import javax.xml.namespace.QName;
 import javax.xml.stream.Location;
@@ -115,4 +116,10 @@ public interface ConfigMessages {
 
     @Message(id = 24, value = "Failed to parse CIDR address value of attribute \"%s\": \"%s\" is not a valid CIDR address")
     ConfigXMLParseException cidrAddressParseException(QName attributeName, String address, @Param(Location.class) XMLLocation location);
+
+    @Message(id = 25, value = "Failed to load a resolver for the encrypted expression.")
+    ConfigXMLParseException failedToLoadResolver();
+
+    @Message(id = 26, value = "Failed to load the \"%s\" class using a service loader.")
+    ServiceConfigurationError failedToLoadUsingServiceLoader(String className);
 }