add ability to create keystores

Author: SylvainJuge

jmx-scraper/build.gradle.kts

@@ -37,6 +37,8 @@ testing {
         implementation("com.linecorp.armeria:armeria-junit5")
         implementation("com.linecorp.armeria:armeria-grpc")
         implementation("io.opentelemetry.proto:opentelemetry-proto:1.5.0-alpha")
+        implementation("org.bouncycastle:bcprov-jdk18on:1.80")
+        implementation("org.bouncycastle:bcpkix-jdk18on:1.80")
       }
     }
   }

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/TestKeyStoreUtil.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.jmxscraper;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.math.BigInteger;
+import java.nio.file.Path;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.KeyStore;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.cert.X509Certificate;
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.Date;
+import org.bouncycastle.asn1.x500.X500Name;
+import org.bouncycastle.cert.X509v3CertificateBuilder;
+import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
+import org.bouncycastle.cert.jcajce.JcaX509v3CertificateBuilder;
+import org.bouncycastle.operator.ContentSigner;
+import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
+
+/** Utility that allows to manage keystores programmatically without using 'keytool' CLI program */
+class TestKeyStoreUtil {
+
+  private TestKeyStoreUtil() {}
+
+  /**
+   * Creates a keystore with a public/private key pair
+   *
+   * @param path path to key store
+   * @param password key store password
+   * @return self-signed certificate of the public/private key pair
+   */
+  @CanIgnoreReturnValue
+  static X509Certificate createKeyStore(Path path, String password) {
+
+    try {
+      KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
+      keyPairGenerator.initialize(2048);
+      KeyPair keyPair = keyPairGenerator.generateKeyPair();
+      PrivateKey privateKey = keyPair.getPrivate();
+
+      X509Certificate certificate = createSelfSignedCertificate(keyPair);
+
+      KeyStore keyStore = KeyStore.getInstance("JKS");
+      keyStore.load(null, null);
+
+      // for convenience reuse keystore password for key password
+      keyStore.setKeyEntry(
+          "key", privateKey, password.toCharArray(), new X509Certificate[] {certificate});
+
+      try (FileOutputStream fos = new FileOutputStream(path.toFile())) {
+        keyStore.store(fos, password.toCharArray());
+      }
+
+      return certificate;
+    } catch (Exception e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  private static X509Certificate createSelfSignedCertificate(KeyPair keyPair) {
+    try {
+      PublicKey publicKey = keyPair.getPublic();
+      PrivateKey privateKey = keyPair.getPrivate();
+
+      Instant now = Instant.now();
+
+      X500Name issuer = new X500Name("CN=Self-Signed Certificate");
+      X500Name subject = new X500Name("CN=Self-Signed Certificate");
+      BigInteger serial = BigInteger.valueOf(now.toEpochMilli());
+
+      X509v3CertificateBuilder certBuilder =
+          new JcaX509v3CertificateBuilder(
+              issuer,
+              serial,
+              Date.from(now.minus(1, ChronoUnit.DAYS)), // 1 day ago
+              Date.from(now.plus(1, ChronoUnit.DAYS)), // 1 day from now
+              subject,
+              publicKey);
+
+      ContentSigner signer = new JcaContentSignerBuilder("SHA256withRSA").build(privateKey);
+      return new JcaX509CertificateConverter().getCertificate(certBuilder.build(signer));
+    } catch (Exception e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  /**
+   * Adds trusted certificate
+   *
+   * @param path path to key store
+   * @param password key store password
+   * @param certificate certificate to trust
+   */
+  public static void addTrustedCertificate(
+      Path path, String password, X509Certificate certificate) {
+
+    try {
+      KeyStore keyStore = KeyStore.getInstance("JKS");
+
+      try (FileInputStream fis = new FileInputStream(path.toFile())) {
+        keyStore.load(fis, password.toCharArray());
+      }
+
+      keyStore.setCertificateEntry("trustedCertificate", certificate);
+
+      try (FileOutputStream fos = new FileOutputStream(path.toFile())) {
+        keyStore.store(fos, password.toCharArray());
+      }
+    } catch (Exception e) {
+      throw new IllegalStateException(e);
+    }
+  }
+}