Fix for #196. Support configurable Config Sources.

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

@@ -0,0 +1,8 @@
+package io.smallrye.config;
+
+import io.smallrye.common.annotation.Experimental;
+
+@Experimental("")
+public interface ConfigSourceContext {
+    ConfigValue getValue(String name);
+}

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

@@ -0,0 +1,16 @@
+package io.smallrye.config;
+
+import java.util.OptionalInt;
+
+import org.eclipse.microprofile.config.spi.ConfigSource;
+
+import io.smallrye.common.annotation.Experimental;
+
+@Experimental("")
+public interface ConfigSourceFactory {
+    ConfigSource getSource(ConfigSourceContext context);
+
+    default OptionalInt getPriority() {
+        return OptionalInt.empty();
+    }
+}

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

@@ -92,6 +92,11 @@ List<ConfigSource> discoverSources() {
                 classLoader);
         configSourceProviderLoader.forEach(configSourceProvider -> configSourceProvider.getConfigSources(classLoader)
                 .forEach(discoveredSources::add));
+
+        ServiceLoader<ConfigSourceFactory> configSourceFactoryLoader = ServiceLoader.load(ConfigSourceFactory.class,
+                classLoader);
+        configSourceFactoryLoader.forEach(this::withSources);
+
         return discoveredSources;
     }
 
@@ -186,6 +191,24 @@ public SmallRyeConfigBuilder withSources(Collection<ConfigSource> configSources)
         return this;
     }
 
+    public SmallRyeConfigBuilder withSources(ConfigSourceFactory... configSourceFactories) {
+        Stream.of(configSourceFactories).forEach(configSourceFactory -> {
+            interceptors.add(new InterceptorWithPriority(new ConfigSourceInterceptorFactory() {
+                @Override
+                public ConfigSourceInterceptor getInterceptor(final ConfigSourceInterceptorContext context) {
+                    return SmallRyeConfigSourceInterceptor.configSourceInterceptor(
+                            configSourceFactory.getSource(context::proceed));
+                }
+
+                @Override
+                public OptionalInt getPriority() {
+                    return configSourceFactory.getPriority();
+                }
+            }));
+        });
+        return this;
+    }
+
     public SmallRyeConfigBuilder withInterceptors(ConfigSourceInterceptor... interceptors) {
         this.interceptors.addAll(Stream.of(interceptors)
                 .map(InterceptorWithPriority::new)

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

@@ -0,0 +1,94 @@
+package io.smallrye.config;
+
+import static java.util.stream.Collectors.toList;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.List;
+import java.util.Map;
+import java.util.OptionalInt;
+import java.util.stream.StreamSupport;
+
+import org.eclipse.microprofile.config.spi.ConfigSource;
+import org.junit.jupiter.api.Test;
+
+import io.smallrye.config.common.AbstractConfigSource;
+
+public class ConfigConfigSourceTest {
+    @Test
+    public void configure() {
+        final SmallRyeConfig config = new SmallRyeConfigBuilder()
+                .addDefaultSources()
+                .addDefaultInterceptors()
+                .withSources(KeyValuesConfigSource.config("my.prop", "1234"))
+                .withSources(new ConfigSourceFactory() {
+                    @Override
+                    public ConfigSource getSource(final ConfigSourceContext context) {
+                        return new AbstractConfigSource("test", 1000) {
+                            final String value = context.getValue("my.prop").getValue();
+
+                            @Override
+                            public Map<String, String> getProperties() {
+                                return null;
+                            }
+
+                            @Override
+                            public String getValue(final String propertyName) {
+                                return value;
+                            }
+                        };
+                    }
+
+                    @Override
+                    public OptionalInt getPriority() {
+                        return OptionalInt.of(1000);
+                    }
+                })
+                .build();
+
+        final List<ConfigSource> configSources = StreamSupport.stream(config.getConfigSources().spliterator(), false)
+                .collect(toList());
+        assertEquals(1, configSources.stream().filter(source -> source.getName().equals("test")).count());
+
+        assertEquals("1234", config.getRawValue("my.prop"));
+        assertEquals("test", config.getConfigValue("my.prop").getConfigSourceName());
+        assertEquals("1234", config.getRawValue("any"));
+        assertEquals("test", config.getConfigValue("any").getConfigSourceName());
+    }
+
+    @Test
+    public void lowerPriority() {
+        final SmallRyeConfig config = new SmallRyeConfigBuilder()
+                .addDefaultSources()
+                .addDefaultInterceptors()
+                .withSources(KeyValuesConfigSource.config("my.prop", "1234"))
+                .withSources(new ConfigSourceFactory() {
+                    @Override
+                    public ConfigSource getSource(final ConfigSourceContext context) {
+                        return new AbstractConfigSource("test", 0) {
+                            final ConfigValue value = context.getValue("my.prop");
+
+                            @Override
+                            public Map<String, String> getProperties() {
+                                return null;
+                            }
+
+                            @Override
+                            public String getValue(final String propertyName) {
+                                return value != null ? value.getValue() : null;
+                            }
+                        };
+                    }
+
+                    @Override
+                    public OptionalInt getPriority() {
+                        return OptionalInt.of(0);
+                    }
+                })
+                .build();
+
+        assertEquals("1234", config.getRawValue("my.prop"));
+        assertEquals("KeyValuesConfigSource", config.getConfigValue("my.prop").getConfigSourceName());
+        assertNull(config.getRawValue("any"));
+    }
+}

sources/zookeeper/pom.xml

@@ -39,6 +39,11 @@
             <artifactId>smallrye-config-common</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>io.smallrye.config</groupId>
+            <artifactId>smallrye-config</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>org.apache.curator</groupId>
             <artifactId>curator-recipes</artifactId>
@@ -66,12 +71,6 @@
             <artifactId>weld-junit5</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>io.smallrye.config</groupId>
-            <artifactId>smallrye-config</artifactId>
-            <scope>test</scope>
-        </dependency>
-
         <dependency>
             <groupId>org.apache.curator</groupId>
             <artifactId>curator-test</artifactId>
@@ -84,7 +83,6 @@
                 </exclusion>
             </exclusions>
         </dependency>
-
     </dependencies>
 
     <profiles>

sources/zookeeper/src/main/java/io/smallrye/config/source/zookeeper/ZooKeeperConfigException.java

@@ -1,6 +1,6 @@
 package io.smallrye.config.source.zookeeper;
 
-public class ZooKeeperConfigException extends Exception {
+public class ZooKeeperConfigException extends RuntimeException {
 
     public ZooKeeperConfigException() {
         super();

sources/zookeeper/src/main/java/io/smallrye/config/source/zookeeper/ZooKeeperConfigSource.java

@@ -1,14 +1,11 @@
 package io.smallrye.config.source.zookeeper;
 
 import java.util.*;
-import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
 import org.apache.curator.retry.ExponentialBackoffRetry;
 import org.apache.zookeeper.data.Stat;
-import org.eclipse.microprofile.config.Config;
-import org.eclipse.microprofile.config.ConfigProvider;
 
 import io.smallrye.config.common.AbstractConfigSource;
 
@@ -23,26 +20,32 @@
 public class ZooKeeperConfigSource extends AbstractConfigSource {
     private static final long serialVersionUID = 3127679154588598693L;
 
-    //Apache Curator framework used to access Zookeeper
-    private AtomicReference<CuratorFramework> curatorReference = new AtomicReference<>();
-
-    //Root node of an application's configuration
-    private String applicationId;
-
-    //Prefix of ignored properties
-    private static final String IGNORED_PREFIX = "io.smallrye.configsource.zookeeper";
-
     //Property the URL of the Zookeeper instance will be read from
     static final String ZOOKEEPER_URL_KEY = "io.smallrye.configsource.zookeeper.url";
-
     //Property of the Application Id. This will be the root znode for an application's properties
     static final String APPLICATION_ID_KEY = "io.smallrye.configsource.zookeeper.applicationId";
 
     //Name of this ConfigSource
     private static final String ZOOKEEPER_CONFIG_SOURCE_NAME = "io.smallrye.configsource.zookeeper";
 
-    public ZooKeeperConfigSource() {
+    //Apache Curator framework used to access Zookeeper
+    private final CuratorFramework curator;
+    //Root node of an application's configuration
+    private final String applicationId;
+
+    public ZooKeeperConfigSource(final String zookeeperUrl, final String applicationId) {
         super(ZOOKEEPER_CONFIG_SOURCE_NAME, 150);
+
+        //Only create the ZK Client if the properties exist.
+        if (zookeeperUrl != null && applicationId != null) {
+            ZooKeepperLogging.log.configuringZookeeper(zookeeperUrl, applicationId);
+
+            this.applicationId = applicationId.startsWith("/") ? applicationId : "/" + applicationId;
+            this.curator = CuratorFrameworkFactory.newClient(zookeeperUrl, new ExponentialBackoffRetry(1000, 3));
+            this.curator.start();
+        } else {
+            throw ZooKeeperMessages.msg.propertiesNotSet();
+        }
     }
 
     @Override
@@ -51,7 +54,7 @@ public Set<String> getPropertyNames() {
         final Set<String> propertyNames = new HashSet<>();
 
         try {
-            final List<String> children = getCuratorClient().getChildren().forPath(applicationId);
+            final List<String> children = curator.getChildren().forPath(applicationId);
             propertyNames.addAll(children);
         } catch (Exception e) {
             ZooKeepperLogging.log.failedToRetrievePropertyNames(e);
@@ -66,9 +69,9 @@ public Map<String, String> getProperties() {
         final Map<String, String> props = new HashMap<>();
 
         try {
-            final List<String> children = getCuratorClient().getChildren().forPath(applicationId);
+            final List<String> children = curator.getChildren().forPath(applicationId);
             for (final String key : children) {
-                final String value = new String(getCuratorClient().getData().forPath(applicationId + "/" + key));
+                final String value = new String(curator.getData().forPath(applicationId + "/" + key));
                 props.put(key, value);
             }
         } catch (Exception e) {
@@ -80,20 +83,11 @@ public Map<String, String> getProperties() {
 
     @Override
     public String getValue(final String key) {
-
-        /*
-         * Explicitly ignore all keys that are prefixed with the prefix used to configure the Zookeeper connection.
-         * Other wise a stack overflow obviously happens.
-         */
-        // TODO - radcortez - We need to add a feature that allows ConfigSource to config itself with other ConfigSource
-        if (key.startsWith(IGNORED_PREFIX) || key.startsWith("smallrye.config")) {
-            return null;
-        }
         try {
-            final Stat stat = getCuratorClient().checkExists().forPath(applicationId + "/" + key);
+            final Stat stat = curator.checkExists().forPath(applicationId + "/" + key);
 
             if (stat != null) {
-                return new String(getCuratorClient().getData().forPath(applicationId + "/" + key));
+                return new String(curator.getData().forPath(applicationId + "/" + key));
             } else {
                 return null;
             }
@@ -102,35 +96,4 @@ public String getValue(final String key) {
         }
         return null;
     }
-
-    private CuratorFramework getCuratorClient() throws ZooKeeperConfigException {
-
-        CuratorFramework cachedClient = curatorReference.get();
-        if (cachedClient == null) {
-
-            final Config cfg = ConfigProvider.getConfig();
-
-            final Optional<String> zookeeperUrl = cfg.getOptionalValue(ZOOKEEPER_URL_KEY, String.class);
-            final Optional<String> optApplicationId = cfg.getOptionalValue(APPLICATION_ID_KEY, String.class);
-
-            //Only create the ZK Client if the properties exist.
-            if (zookeeperUrl.isPresent() && optApplicationId.isPresent()) {
-
-                ZooKeepperLogging.log.configuringZookeeper(zookeeperUrl.get(), optApplicationId.get());
-
-                applicationId = optApplicationId.get();
-
-                if (!applicationId.startsWith("/")) {
-                    applicationId = "/" + applicationId;
-                }
-                cachedClient = CuratorFrameworkFactory.newClient(zookeeperUrl.get(), new ExponentialBackoffRetry(1000, 3));
-                curatorReference.compareAndSet(null, cachedClient);
-                cachedClient.start();
-
-            } else {
-                throw ZooKeeperMessages.msg.propertiesNotSet();
-            }
-        }
-        return cachedClient;
-    }
 }

sources/zookeeper/src/main/java/io/smallrye/config/source/zookeeper/ZooKeeperConfigSourceFactory.java

@@ -0,0 +1,21 @@
+package io.smallrye.config.source.zookeeper;
+
+import java.util.OptionalInt;
+
+import org.eclipse.microprofile.config.spi.ConfigSource;
+
+import io.smallrye.config.ConfigSourceContext;
+import io.smallrye.config.ConfigSourceFactory;
+
+public class ZooKeeperConfigSourceFactory implements ConfigSourceFactory {
+    @Override
+    public ConfigSource getSource(final ConfigSourceContext context) {
+        return new ZooKeeperConfigSource(context.getValue(ZooKeeperConfigSource.ZOOKEEPER_URL_KEY).getValue(),
+                context.getValue(ZooKeeperConfigSource.APPLICATION_ID_KEY).getValue());
+    }
+
+    @Override
+    public OptionalInt getPriority() {
+        return OptionalInt.of(150);
+    }
+}

sources/zookeeper/src/main/resources/META-INF/services/io.smallrye.config.ConfigSourceFactory

@@ -0,0 +1 @@
+io.smallrye.config.source.zookeeper.ZooKeeperConfigSourceFactory