Add support for Vault (#42)

* Add support for Vault

config-vault/pom.xml

@@ -0,0 +1,39 @@
+<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>
+    <properties>
+        <enforcer.skip>true</enforcer.skip>
+    </properties>
+
+	<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>
+		<dependency>
+			<groupId>org.testcontainers</groupId>
+			<artifactId>vault</artifactId>
+			<version>1.6.0</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>co.unruly</groupId>
+			<artifactId>java-8-matchers</artifactId>
+			<version>1.5</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+</project>

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

@@ -0,0 +1,136 @@
+package io.scalecube.config.vault;
+
+import static java.util.Objects.requireNonNull;
+
+import io.scalecube.config.ConfigProperty;
+import io.scalecube.config.ConfigSourceNotAvailableException;
+import io.scalecube.config.source.ConfigSource;
+import io.scalecube.config.source.LoadedConfigProperty;
+import io.scalecube.config.utils.ThrowableUtil;
+
+import com.bettercloud.vault.EnvironmentLoader;
+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 org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+/**
+ * This class is a {@link ConfigSource} implemented for Vault
+ * 
+ * @see <a href="https://www.vaultproject.io/">Vault Project</a>
+ */
+public class VaultConfigSource implements ConfigSource {
+
+  static final Logger LOGGER = LoggerFactory.getLogger(VaultConfigSource.class);
+
+  private final Vault vault;
+  private final String secretsPath;
+
+  /**
+   * Create a new {@link VaultConfigSource} with the given {@link Builder}. <br>
+   * 
+   * @param builder configuration to create vault access with.
+   * 
+   */
+  VaultConfigSource(Builder builder) {
+    this.secretsPath = builder.secretsPath();
+    vault = new Vault(builder.config);
+  }
+
+  private void checkVaultStatus() throws VaultException {
+    if (vault.seal().sealStatus().getSealed()) {
+      throw new VaultException("Vault is sealed");
+    }
+    Boolean initialized = vault.debug().health().getInitialized();
+    if (!initialized) {
+      throw new VaultException("Vault not yet initialized");
+    }
+  }
+
+  @Override
+  public Map<String, ConfigProperty> loadConfig() {
+    try {
+      checkVaultStatus();
+      LogicalResponse response = vault.logical().read(this.secretsPath);
+      return response.getData().entrySet().stream().map(LoadedConfigProperty::withNameAndValue)
+          .map(LoadedConfigProperty.Builder::build)
+          .collect(Collectors.toMap(LoadedConfigProperty::name, Function.identity()));
+    } catch (VaultException vaultException) {
+      LOGGER.warn("unable to load config properties", vaultException);
+      throw new ConfigSourceNotAvailableException(vaultException);
+    }
+  }
+
+  /**
+   * This builder method is used internally for test purposes. please use it only for tests. Please note the following
+   * required environment variables are required.
+   * <ul>
+   * <li><code>VAULT_SECRETS_PATH</pre> is the path to use (defaults to <code>secret</code>)</li>
+   * <li><code>VAULT_TOKEN</code> is the {@link VaultConfig#token(String) token} to use</li>
+   * <li><code>VAULT_ADDR</code> is the {@link VaultConfig#address(String) address} of the vault (API)</li>
+   * </ul>
+   */
+  public static Builder builder() {
+    return builder(new EnvironmentLoader());
+  }
+
+  /**
+   * This builder method is used internally for test purposes. please use it only for tests
+   *
+   * @param environmentLoader an {@link EnvironmentLoader}
+   */
+  static Builder builder(EnvironmentLoader environmentLoader) {
+    return builder(environmentLoader.loadVariable("VAULT_ADDR"),
+        environmentLoader.loadVariable("VAULT_TOKEN"),
+        environmentLoader.loadVariable("VAULT_SECRETS_PATH"));
+  }
+
+  public static Builder builder(String address, String token, String secretsPath) {
+    return new Builder(address, token, secretsPath);
+  }
+
+  public static final class Builder {
+
+    final VaultConfig config = new VaultConfig();
+    private final String secretsPath;
+
+    Builder(String address, String token, String secretsPath) {
+      config.address(requireNonNull(address, "Missing address"))
+          .token(requireNonNull(token, "Missing token"))
+          .sslConfig(new SslConfig());
+      this.secretsPath = requireNonNull(secretsPath, "Missing secretsPath");
+    }
+
+    public Builder connectTimeout(int connectTimeout) {
+      config.openTimeout(connectTimeout);
+      return this;
+    }
+
+    public Builder readTimeout(int readTimeout) {
+      config.readTimeout(readTimeout);
+      return this;
+    }
+
+    public VaultConfigSource build() {
+      try {
+        this.config.build();
+        return new VaultConfigSource(this);
+      } catch (VaultException propogateException) {
+        LOGGER.error("Unable to build " + VaultConfigSource.class.getSimpleName(), propogateException);
+        throw ThrowableUtil.propagate(propogateException);
+      }
+    }
+
+    public String secretsPath() {
+      return secretsPath;
+    }
+  }
+}