Merge pull request #266 from radcortez/#198

#Fixed 198 - Add interceptor to expand expressions in Config Values.

implementation/pom.xml

@@ -49,6 +49,11 @@
  <groupId>io.smallrye.config</groupId>
  <artifactId>smallrye-config-common</artifactId>
  </dependency>
+ <dependency>
+ <groupId>io.smallrye.common</groupId>
+ <artifactId>smallrye-common-expression</artifactId>
+ </dependency>
+
  <dependency>
  <groupId>org.jboss.logging</groupId>
  <artifactId>jboss-logging</artifactId>

implementation/src/main/java/io/smallrye/config/ExpressionConfigSourceInterceptor.java

@@ -0,0 +1,59 @@
+package io.smallrye.config;
+
+import static io.smallrye.common.expression.Expression.Flag.LENIENT_SYNTAX;
+import static io.smallrye.common.expression.Expression.Flag.NO_TRIM;
+
+import java.util.NoSuchElementException;
+
+import javax.annotation.Priority;
+
+import io.smallrye.common.expression.Expression;
+
+@Priority(500)
+public class ExpressionConfigSourceInterceptor implements ConfigSourceInterceptor {
+ private static final ThreadLocal<Boolean> ENABLE = ThreadLocal.withInitial(() -> Boolean.TRUE);
+
+ @Override
+ public ConfigValue getValue(final ConfigSourceInterceptorContext context, final String name) {
+ final ConfigValue configValue = context.proceed(name);
+
+ if (!ENABLE.get()) {
+ return configValue;
+ }
+
+ if (configValue == null) {
+ return null;
+ }
+
+ final Expression expression = Expression.compile(configValue.getValue(), LENIENT_SYNTAX, NO_TRIM);
+ final String expanded = expression.evaluate((resolveContext, stringBuilder) -> {
+ final ConfigValue resolve = context.proceed(resolveContext.getKey());
+ if (resolve != null) {
+ stringBuilder.append(resolve.getValue());
+ } else if (resolveContext.hasDefault()) {
+ resolveContext.expandDefault();
+ } else {
+ throw new NoSuchElementException(
+ "Could not expand value " + resolveContext.getKey() + " in property " + configValue.getName());
+ }
+ });
+
+ return configValue.withValue(expanded);
+ }
+
+ static boolean enable() {
+ try {
+ return ENABLE.get() == Boolean.FALSE;
+ } finally {
+ ENABLE.set(Boolean.TRUE);
+ }
+ }
+
+ static boolean disable() {
+ try {
+ return ENABLE.get() == Boolean.TRUE;
+ } finally {
+ ENABLE.set(Boolean.FALSE);
+ }
+ }
+}

implementation/src/main/java/io/smallrye/config/Expressions.java

@@ -0,0 +1,18 @@
+package io.smallrye.config;
+
+import static io.smallrye.config.ExpressionConfigSourceInterceptor.disable;
+import static io.smallrye.config.ExpressionConfigSourceInterceptor.enable;
+
+public class Expressions {
+ public static void withoutExpansion(final Runnable action) {
+ if (disable()) {
+ try {
+ action.run();
+ } finally {
+ enable();
+ }
+ } else {
+ action.run();
+ }
+ }
+}

implementation/src/test/java/io/smallrye/config/ExpressionConfigSourceInterceptorTest.java

@@ -0,0 +1,100 @@
+package io.smallrye.config;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+
+import java.util.NoSuchElementException;
+
+import org.eclipse.microprofile.config.Config;
+import org.junit.Test;
+
+public class ExpressionConfigSourceInterceptorTest {
+ @Test
+ public void simpleExpression() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("my.prop", "1234", "expression", "${my.prop}");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void multipleExpressions() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("my.prop", "1234", "expression", "${my.prop}${my.prop}");
+
+ assertEquals("12341234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void composedExpressions() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("my.prop", "1234", "expression", "${${compose}}", "compose",
+ "my.prop");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void defaultExpression() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "${my.prop:1234}");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void defaultExpressionEmpty() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "12${my.prop:}34");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void defaultExpressionComposed() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "${my.prop:${compose}}", "compose", "1234");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void defaultExpressionComposedEmpty() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "${my.prop:${compose:}}", "my.prop", "1234");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ @Test
+ public void noExpression() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "${my.prop}");
+
+ final NoSuchElementException exception = assertThrows(NoSuchElementException.class,
+ () -> config.getValue("expression", String.class));
+ assertEquals("Could not expand value my.prop in property expression", exception.getMessage());
+ }
+
+ @Test
+ public void noExpressionComposed() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("expression", "${my.prop${compose}}");
+
+ final NoSuchElementException exception = assertThrows(NoSuchElementException.class,
+ () -> config.getValue("expression", String.class));
+ assertEquals("Could not expand value compose in property expression", exception.getMessage());
+ }
+
+ @Test
+ public void withoutExpansion() {
+ SmallRyeConfig config = (SmallRyeConfig) buildConfig("my.prop", "1234", "expression", "${my.prop}");
+
+ assertEquals("1234", config.getValue("expression", String.class));
+
+ Expressions.withoutExpansion(() -> assertEquals("${my.prop}", config.getValue("expression", String.class)));
+ Expressions.withoutExpansion(() -> assertEquals("${my.prop}", config.getValue("expression", String.class)));
+ Expressions.withoutExpansion(() -> assertEquals("${my.prop}", config.getValue("expression", String.class)));
+
+ assertEquals("1234", config.getValue("expression", String.class));
+ }
+
+ private static Config buildConfig(String... keyValues) {
+ return new SmallRyeConfigBuilder()
+ .addDefaultSources()
+ .withSources(KeyValuesConfigSource.config(keyValues))
+ .withInterceptors(new ExpressionConfigSourceInterceptor())
+ .build();
+ }
+}

pom.xml

@@ -35,6 +35,7 @@
 
  <properties>
  <version.eclipse.microprofile.config>1.4</version.eclipse.microprofile.config>
+ <version.smallrye.common>1.0.0</version.smallrye.common>
 
  <!-- Sonar settings -->
  <sonar.projectName>SmallRye Config</sonar.projectName>
@@ -106,6 +107,13 @@
  </exclusions>
  </dependency>
 
+ <!-- External SmallRye Dependencies -->
+ <dependency>
+ <groupId>io.smallrye.common</groupId>
+ <artifactId>smallrye-common-expression</artifactId>
+ <version>${version.smallrye.common}</version>
+ </dependency>
+
  <!-- Dependencies provided by the project -->
  <dependency>
  <groupId>io.smallrye.config</groupId>