Add method for creating an SSLContext that merges both the trust store and custom certificates

keystores/src/main/java/com/palantir/conjure/java/config/ssl/KeyStores.java

@@ -122,6 +122,12 @@ static KeyStore createTrustStoreFromCertificates(Map<String, PemX509Certificate>
         KeyStore keyStore;
         keyStore = createKeyStore();
 
+        addCertificatesToKeystore(certificatesByAlias, keyStore);
+
+        return keyStore;
+    }
+
+    static void addCertificatesToKeystore(Map<String, PemX509Certificate> certificatesByAlias, KeyStore keyStore) {
         for (Map.Entry<String, PemX509Certificate> entry : certificatesByAlias.entrySet()) {
             try (InputStream certIn =
                     new ByteArrayInputStream(entry.getValue().pemCertificate().getBytes(StandardCharsets.UTF_8))) {
@@ -135,8 +141,6 @@ static KeyStore createTrustStoreFromCertificates(Map<String, PemX509Certificate>
                         e);
             }
         }
-
-        return keyStore;
     }
 
     private static void addCertificatesToKeystore(

keystores/src/main/java/com/palantir/conjure/java/config/ssl/SslSocketFactories.java

@@ -18,6 +18,7 @@
 
 import com.google.common.base.Throwables;
 import com.palantir.conjure.java.api.config.ssl.SslConfiguration;
+import com.palantir.conjure.java.api.config.ssl.SslConfiguration.StoreType;
 import com.palantir.logsafe.SafeArg;
 import com.palantir.logsafe.exceptions.SafeRuntimeException;
 import java.nio.file.Path;
@@ -91,6 +92,20 @@ public static SSLSocketFactory createSslSocketFactory(
         return sslContext.getSocketFactory();
     }
 
+    /**
+     * Create a {@link SSLSocketFactory} by merging the provided certificates and configuration.
+     *
+     * @param trustCertificatesByAlias a map of X.509 certificate in PEM or DER format by the alias to load the
+     *     certificate as.
+     * @param config an {@link SslConfiguration} describing the trust store configuration
+     * @param provider The preferred security {@link Provider}
+     */
+    public static SSLSocketFactory createSslSocketFactory(
+            Map<String, PemX509Certificate> trustCertificatesByAlias, SslConfiguration config, Provider provider) {
+        SSLContext sslContext = createSslContext(config, trustCertificatesByAlias, provider);
+        return sslContext.getSocketFactory();
+    }
+
     /**
      * Create an {@link SSLContext} initialized from the provided configuration.
      *
@@ -142,6 +157,20 @@ public static SSLContext createSslContext(
         return createSslContext(trustManagers, new KeyManager[] {}, provider);
     }
 
+    /**
+     * Create an {@link SSLContext} by merging the provided configuration and certificates.
+     *
+     * @param trustCertificatesByAlias a map of X.509 certificate in PEM or DER format by the alias to load the
+     *       certificate as.
+     * @param config an {@link SslConfiguration} describing the trust store configuration
+     * @param provider The preferred security {@link Provider}
+     */
+    public static SSLContext createSslContext(
+            SslConfiguration config, Map<String, PemX509Certificate> trustCertificatesByAlias, Provider provider) {
+        TrustManager[] trustManagers = createMergedTrustManagers(config, trustCertificatesByAlias);
+        return createSslContext(trustManagers, new KeyManager[] {}, provider);
+    }
+
     /**
      * Create an {@link SSLContext} initialized from the provided certificates.
      * @see SSLContext#init(KeyManager[], TrustManager[], SecureRandom)
@@ -200,6 +229,20 @@ public static TrustManager[] createTrustManagers(Map<String, PemX509Certificate>
         }
     }
 
+    /**
+     * Create SSL socket factory and trust manager by merging the given certificates and configuration,
+     * see {@link #createX509TrustManager} and {@link #createSslSocketFactory}.
+     */
+    public static TrustManager[] createMergedTrustManagers(
+            SslConfiguration config, Map<String, PemX509Certificate> trustCertificatesByAlias) {
+        KeyStore keystore = getCombinedTrustStoreAndDefaultCas(config.trustStorePath(), config.trustStoreType());
+
+        KeyStores.addCertificatesToKeystore(trustCertificatesByAlias, keystore);
+
+        return ConscryptCompatTrustManagers.wrap(
+                getTrustManagerFactory(keystore).getTrustManagers());
+    }
+
     /**
      * Create SSL socket factory and trust manager from the given configuration, see {@link #createX509TrustManager} and
      * {@link #createSslSocketFactory}.
@@ -269,6 +312,23 @@ public static KeyManager[] createKeyManagers(SslConfiguration config) {
 
     private static TrustManagerFactory createTrustManagerFactory(
             Path trustStorePath, SslConfiguration.StoreType trustStoreType) {
+        KeyStore keyStore = getCombinedTrustStoreAndDefaultCas(trustStorePath, trustStoreType);
+
+        return getTrustManagerFactory(keyStore);
+    }
+
+    private static TrustManagerFactory getTrustManagerFactory(KeyStore keyStore) {
+        try {
+            TrustManagerFactory trustManagerFactory =
+                    TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
+            trustManagerFactory.init(keyStore);
+            return trustManagerFactory;
+        } catch (GeneralSecurityException e) {
+            throw Throwables.propagate(e);
+        }
+    }
+
+    private static KeyStore getCombinedTrustStoreAndDefaultCas(Path trustStorePath, StoreType trustStoreType) {
         KeyStore keyStore;
         switch (trustStoreType) {
             case JKS:
@@ -299,15 +359,7 @@ private static TrustManagerFactory createTrustManagerFactory(
                         "Unable to add certificate to store", e, SafeArg.of("certificateAlias", certAlias));
             }
         });
-
-        try {
-            TrustManagerFactory trustManagerFactory =
-                    TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
-            trustManagerFactory.init(keyStore);
-            return trustManagerFactory;
-        } catch (GeneralSecurityException e) {
-            throw Throwables.propagate(e);
-        }
+        return keyStore;
     }
 
     private static KeyManagerFactory createKeyManagerFactory(