[AD-1049] Refactor internal SSH tunnel to be single-instance per process. (#472)

* [AD-1049] Refactor internal SSH tunnel to be single-instance per process.

* [AD-1049] Fix portability of connection timeout test.

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* [AD-1049] Corrected tracing text to be more consistent.

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* [AD-1049] Improved readability of close code.

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* [AD-1049] Code review improvements.

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* [AD-1049] Code review improvements #2.

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* [AD-1049] Remove unused InterruptedException.

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Co-authored-by: birschick-bq <birschick-bq@users.noreply.github.com>

Author: Bruce Irschick

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@@ -57,7 +57,6 @@
 import software.amazon.documentdb.jdbc.metadata.DocumentDbSchemaColumn;
 import software.amazon.documentdb.jdbc.metadata.DocumentDbSchemaTable;
 import software.amazon.documentdb.jdbc.persist.DocumentDbSchemaSecurityException;
-import software.amazon.documentdb.jdbc.sshtunnel.DocumentDbSshTunnelService;
 
 import java.io.Console;
 import java.io.File;
@@ -118,7 +117,6 @@ public class DocumentDbMain {
     private static final Options HELP_VERSION_OPTIONS;
     private static final Option HELP_OPTION;
     private static final Option VERSION_OPTION;
-    private static final Options SSH_TUNNEL_SERVICE_OPTIONS;
     private static final OptionGroup COMMAND_OPTIONS;
     private static final List<Option> REQUIRED_OPTIONS;
     private static final List<Option> OPTIONAL_OPTIONS;
@@ -161,7 +159,6 @@ public class DocumentDbMain {
     private static final String USER_OPTION_FLAG = "u";
     private static final String USER_OPTION_NAME = "user";
     private static final String VERSION_OPTION_NAME = "version";
-    public static final String SSH_TUNNEL_SERVICE_OPTION_NAME = "ssh-tunnel-service";
     // Option argument string constants
     private static final String DATABASE_NAME_ARG_NAME = "database-name";
     private static final String FILE_NAME_ARG_NAME = "file-name";
@@ -170,7 +167,6 @@ public class DocumentDbMain {
     private static final String METHOD_ARG_NAME = "method";
     private static final String USER_NAME_ARG_NAME = "user-name";
     private static final String TABLE_NAMES_ARG_NAME = "[table-name[,...]]";
-    private static final String SSH_TUNNEL_SERVICE_ARG_NAME = "ssh-properties";
     // Option description string constants
     private static final String GENERATE_NEW_OPTION_DESCRIPTION =
             "Generates a new schema for the database. "
@@ -230,8 +226,6 @@ public class DocumentDbMain {
     private static final String OUTPUT_OPTION_DESCRIPTION =
             "Write the exported schema to <file-name> in your home directory (instead of stdout)."
                     + " This will overwrite any existing file with the same name";
-    private static final String SSH_TUNNEL_SERVICE_OPTION_DESCRIPTION =
-            "Starts an SSH Tunnel service.";
     // Messages string constants
     public static final String DUPLICATE_COLUMN_KEY_DETECTED_FOR_TABLE_SCHEMA =
             "Duplicate column key '%s' detected for table schema '%s'. Original column '%s'."
@@ -247,7 +241,6 @@ public class DocumentDbMain {
         LIBRARY_NAME = getLibraryName();
         HELP_OPTION = buildHelpOption();
         VERSION_OPTION = buildVersionOption();
-        SSH_TUNNEL_SERVICE_OPTIONS = buildSshTunnelServiceOption();
         COMMAND_OPTIONS = buildCommandOptions();
         REQUIRED_OPTIONS = buildRequiredOptions();
         OPTIONAL_OPTIONS = buildOptionalOptions();
@@ -348,13 +341,6 @@ static void handleCommandLine(final String[] args, final StringBuilder output)
         }
         try {
             final CommandLineParser parser = new DefaultParser();
-            // First check for the SSH tunnel service option separately from the other options.
-            final CommandLine commandLineSshTunnelService = parser.parse(SSH_TUNNEL_SERVICE_OPTIONS, args, true);
-            if (commandLineSshTunnelService.hasOption(SSH_TUNNEL_SERVICE_OPTION_NAME)) {
-                performSshTunnelService(commandLineSshTunnelService, output);
-                return;
-            }
-            // Otherwise, consider the "complete" options for metadata options.
             final CommandLine commandLine = parser.parse(COMPLETE_OPTIONS, args);
             final DocumentDbConnectionProperties properties = new DocumentDbConnectionProperties();
             if (!tryGetConnectionProperties(commandLine, properties, output)) {
@@ -420,30 +406,6 @@ private static void closeClient() {
         }
     }
 
-    private static void performSshTunnelService(
-            final CommandLine commandLine,
-            final StringBuilder output) throws DuplicateKeyException {
-        try (DocumentDbSshTunnelService service = new DocumentDbSshTunnelService(
-                    commandLine.getOptionValue(SSH_TUNNEL_SERVICE_OPTION_NAME))) {
-            final Thread serviceThread = new Thread(service);
-            serviceThread.setDaemon(true);
-            serviceThread.start();
-            do {
-                serviceThread.join(1000);
-            } while (serviceThread.isAlive());
-            service.getExceptions().forEach(
-                    e -> output
-                            .append(e.getMessage())
-                            .append(System.lineSeparator())
-                            .append(Arrays.stream(e.getStackTrace())
-                                    .map(StackTraceElement::toString)
-                                    .collect(Collectors.joining(System.lineSeparator())))
-                            .append(System.lineSeparator()));
-        } catch (Exception e) {
-            output.append(e.getMessage());
-        }
-    }
-
     private static void performImport(
             final CommandLine commandLine,
             final DocumentDbConnectionProperties properties,
@@ -1034,16 +996,6 @@ private static Option buildVersionOption() {
                 .build();
     }
 
-    private static Options buildSshTunnelServiceOption() {
-        return new Options().addOption(
-                Option.builder()
-                        .longOpt(SSH_TUNNEL_SERVICE_OPTION_NAME)
-                        .desc(SSH_TUNNEL_SERVICE_OPTION_DESCRIPTION)
-                        .numberOfArgs(1)
-                        .argName(SSH_TUNNEL_SERVICE_ARG_NAME)
-                        .build());
-    }
-
     private static Option buildHelpOption() {
         return Option.builder(HELP_OPTION_FLAG)
                 .longOpt(HELP_OPTION_NAME)