Additional "standby clone" code

We'll break up the unwieldy "do_standby_clone()" function into discrete
unit for easier maintenance.

repmgr-action-standby.c

@@ -7,10 +7,19 @@
  */
 
 #include "repmgr.h"
+#include "dirutil.h"
 
 #include "repmgr-client-global.h"
 #include "repmgr-action-standby.h"
 
+static char		local_data_directory[MAXPGPATH];
+
+/* used by barman mode */
+static char		local_repmgr_tmp_directory[MAXPGPATH];
+
+
+static void check_barman_config(void);
+static char *make_barman_ssh_command(char *buf);
 
 
 void
@@ -20,7 +29,7 @@ do_standby_clone(void)
 	PGconn	   *source_conn = NULL;
 	PGresult   *res;
 
-	int			server_version_num = -1;
+	int			server_version_num = UNKNOWN_SERVER_VERSION_NUM;
 	char		cluster_size[MAXLEN];
 
 	/*
@@ -32,6 +41,8 @@ do_standby_clone(void)
 	bool		upstream_record_found = false;
 	int		    upstream_node_id = UNKNOWN_NODE_ID;
 
+	char		upstream_data_directory[MAXPGPATH];
+	bool		local_data_directory_provided = false;
 
 	enum {
 		barman,
@@ -39,19 +50,13 @@ do_standby_clone(void)
 		pg_basebackup
 	}			mode;
 
-	/* used by barman mode */
-	char        datadir_list_filename[MAXLEN];
-	char		local_repmgr_tmp_directory[MAXPGPATH];
-
-	puts("standby clone");
-
 
 	/*
 	 * detecting the cloning mode
 	 */
 	if (runtime_options.rsync_only)
 		mode = rsync;
-	else if (strcmp(config_file_options.barman_server, "") != 0 && ! runtime_options.without_barman)
+	else if (strcmp(config_file_options.barman_host, "") != 0 && ! runtime_options.without_barman)
 		mode = barman;
 	else
 		mode = pg_basebackup;
@@ -72,4 +77,179 @@ do_standby_clone(void)
 		}
 	}
 
+	/*
+	 * If dest_dir (-D/--pgdata) was provided, this will become the new data
+	 * directory (otherwise repmgr will default to using the same directory
+	 * path as on the source host).
+	 *
+	 * Note that barman mode requires -D/--pgdata.
+	 *
+	 * If -D/--pgdata is not supplied, and we're not cloning from barman,
+	 * the source host's data directory will be fetched later, after
+	 * we've connected to it.
+	 */
+	if (runtime_options.data_dir[0])
+	{
+		local_data_directory_provided = true;
+		log_notice(_("destination directory '%s' provided"),
+				   runtime_options.data_dir);
+	}
+	else if (mode == barman)
+	{
+		log_error(_("Barman mode requires a data directory"));
+		log_hint(_("use -D/--pgdata to explicitly specify a data directory"));
+		exit(ERR_BAD_CONFIG);
+	}
+
+	/* Sanity-check barman connection and installation */
+	if (mode == barman)
+	{
+		/* this will exit with ERR_BARMAN if problems found */
+		check_barman_config();
+	}
+
+
+	/*
+	 * target directory (-D/--pgdata) provided - use that as new data directory
+	 * (useful when executing backup on local machine only or creating the backup
+	 * in a different local directory when backup source is a remote host)
+	 */
+	if (local_data_directory_provided == true)
+	{
+		strncpy(local_data_directory, runtime_options.data_dir, MAXPGPATH);
+	}
+
+	/*
+	 * Initialise list of conninfo parameters which will later be used
+	 * to create the `primary_conninfo` string in recovery.conf .
+	 *
+	 * We'll initialise it with the default values as seen by libpq,
+	 * and overwrite them with the host settings specified on the command
+	 * line. As it's possible the standby will be cloned from a node different
+	 * to its intended upstream, we'll later attempt to fetch the
+	 * upstream node record and overwrite the values set here with
+	 * those from the upstream node record (excluding that record's
+	 * application_name)
+	 */
+	initialize_conninfo_params(&recovery_conninfo, true);
+
+	copy_conninfo_params(&recovery_conninfo, &source_conninfo);
+
+	/*
+	 * If application_name is set in repmgr.conf's conninfo parameter, use
+	 * this value (if the source host was provided as a conninfo string, any
+	 * application_name values set there will be overridden; we assume the only
+	 * reason to pass an application_name via the command line is in the
+	 * rare corner case where a user wishes to clone a server without
+	 * providing repmgr.conf)
+	 */
+	if (strlen(config_file_options.conninfo))
+	{
+		char application_name[MAXLEN] = "";
+
+		get_conninfo_value(config_file_options.conninfo, "application_name", application_name);
+		if (strlen(application_name))
+		{
+			param_set(&recovery_conninfo, "application_name", application_name);
+		}
+	}
+
+}
+
+
+
+void
+check_barman_config(void)
+{
+	char		datadir_list_filename[MAXLEN];
+	char		barman_command_buf[MAXLEN] = "";
+
+	char		command[MAXLEN];
+	bool		command_ok;
+
+	/*
+	 * Check that there is at least one valid backup
+	 */
+
+	log_info(_("connecting to Barman server to verify backup for %s"), config_file_options.barman_server);
+
+	maxlen_snprintf(command, "%s show-backup %s latest > /dev/null",
+					make_barman_ssh_command(barman_command_buf),
+				 	config_file_options.barman_server);
+
+	command_ok = local_command(command, NULL);
+
+	if (command_ok == false)
+	{
+		log_error(_("no valid backup for server %s was found in the Barman catalogue"),
+				  config_file_options.barman_server);
+		log_hint(_("refer to the Barman documentation for more information\n"));
+
+		exit(ERR_BARMAN);
+	}
+
+	/*
+	 * Create the local repmgr subdirectory
+	 */
+
+	maxlen_snprintf(local_repmgr_tmp_directory,
+					"%s/repmgr",  local_data_directory);
+
+	maxlen_snprintf(datadir_list_filename,
+					"%s/data.txt", local_repmgr_tmp_directory);
+
+	if (!create_pg_dir(local_data_directory, runtime_options.force))
+	{
+		log_error(_("unable to use directory %s"),
+				local_data_directory);
+		log_hint(_("use -F/--force option to force this directory to be overwritten\n"));
+			exit(ERR_BAD_CONFIG);
+	}
+
+	if (!create_pg_dir(local_repmgr_tmp_directory, runtime_options.force))
+	{
+		log_error(_("unable to create directory \"%s\""),
+				  local_repmgr_tmp_directory);
+
+		exit(ERR_BAD_CONFIG);
+	}
+
+	/*
+	 * Fetch server parameters from Barman
+	 */
+	log_info(_("connecting to Barman server to fetch server parameters"));
+
+	maxlen_snprintf(command, "%s show-server %s > %s/show-server.txt",
+					make_barman_ssh_command(barman_command_buf),
+					config_file_options.barman_server,
+					local_repmgr_tmp_directory);
+
+	command_ok = local_command(command, NULL);
+
+	if (command_ok == false)
+	{
+		log_error(_("unable to fetch server parameters from Barman server"));
+
+		exit(ERR_BARMAN);
+	}
+
+}
+
+
+static char *
+make_barman_ssh_command(char *buf)
+{
+	static char config_opt[MAXLEN] = "";
+
+	if (strlen(config_file_options.barman_config))
+		maxlen_snprintf(config_opt,
+						" --config=%s",
+						config_file_options.barman_config);
+
+	maxlen_snprintf(buf,
+					"ssh %s barman%s",
+					config_file_options.barman_server,
+					config_opt);
+
+	return buf;
 }