Add support for Vault

for issue #2

config-vault/pom.xml

@@ -0,0 +1,24 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>io.scalecube</groupId>
+		<artifactId>config-parent</artifactId>
+		<version>0.3.2-SNAPSHOT</version>
+		<relativePath>../pom.xml</relativePath>
+	</parent>
+	<artifactId>config-vault</artifactId>
+
+	<dependencies>
+		<dependency>
+			<groupId>io.scalecube</groupId>
+			<artifactId>config</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.bettercloud</groupId>
+			<artifactId>vault-java-driver</artifactId>
+			<version>3.1.0</version>
+		</dependency>
+	</dependencies>
+</project>

config-vault/src/main/java/io/scalecube/config/vault/VaultConfigSource.java

@@ -0,0 +1,66 @@
+package io.scalecube.config.vault;
+
+import io.scalecube.config.ConfigProperty;
+import io.scalecube.config.source.ConfigSource;
+import io.scalecube.config.source.LoadedConfigProperty;
+import io.scalecube.config.source.LoadedConfigProperty.Builder;
+
+import com.bettercloud.vault.SslConfig;
+import com.bettercloud.vault.Vault;
+import com.bettercloud.vault.VaultConfig;
+import com.bettercloud.vault.VaultException;
+import com.bettercloud.vault.response.LogicalResponse;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class VaultConfigSource implements ConfigSource {
+
+  private Vault vault;
+  final String SECRET_DEFAULT_PATH;
+
+  public VaultConfigSource() {
+    SECRET_DEFAULT_PATH = System.getenv("VAULT_SECRETS_PATH");
+    VaultConfig config;
+    try {
+      config =
+          new VaultConfig()
+              // Defaults to "VAULT_ADDR" environment variable
+              // .address("http://localhost:8200")
+              // Defaults to "VAULT_TOKEN" environment variable
+              // .token("00000000-0000-0000-0000-000000000000")
+              // Defaults to "VAULT_OPEN_TIMEOUT" environment variable
+              // .openTimeout(5)
+              // Defaults to "VAULT_READ_TIMEOUT" environment variable
+              // .readTimeout(30)
+              // See "SSL Config" section below
+              .sslConfig(new SslConfig().build())
+              .build();
+      vault = new Vault(config);
+      Boolean initialized = vault.debug().health().getInitialized();
+      if (!initialized) {
+        throw new VaultException("Vault yet initialized");
+      }
+      if (vault.seal().sealStatus().getSealed()) {
+        throw new VaultException("Vault is sealed");
+      }
+    } catch (VaultException ignoredException) {
+      ignoredException.printStackTrace();
+    }
+  }
+
+  @Override
+  public Map<String, ConfigProperty> loadConfig() {
+    try {
+      LogicalResponse response = vault.logical().read(SECRET_DEFAULT_PATH);
+
+      return response.getData().entrySet().stream().map(LoadedConfigProperty::withNameAndValue).map(Builder::build)
+          .collect(Collectors.toMap(LoadedConfigProperty::name, Function.identity()));
+    } catch (VaultException ignoredException) {
+      return new HashMap<>();
+    }
+  }
+
+}

pom.xml

@@ -80,6 +80,7 @@
         <module>config-mongo</module>
         <module>config-http-server</module>
         <module>config-examples</module>
+        <module>config-vault</module>
     </modules>
 
     <dependencyManagement>