PGPRO-1184: Add --overwrite option for archive-push

src/archive.c

@@ -22,7 +22,7 @@
  * compute and validate checksums.
  */
 int
-do_archive_push(char *wal_file_path, char *wal_file_name)
+do_archive_push(char *wal_file_path, char *wal_file_name, bool overwrite)
 {
 	char		backup_wal_file_path[MAXPGPATH];
 	char		absolute_wal_file_path[MAXPGPATH];
@@ -62,8 +62,6 @@ do_archive_push(char *wal_file_path, char *wal_file_name)
 	join_path_components(backup_wal_file_path, arclog_path, wal_file_name);
 
 	elog(INFO, "pg_probackup archive-push from %s to %s", absolute_wal_file_path, backup_wal_file_path);
-	if (access(backup_wal_file_path, F_OK) != -1)
-		elog(ERROR, "file '%s', already exists.", backup_wal_file_path);
 
 #ifdef HAVE_LIBZ
 	if (compress_alg == PGLZ_COMPRESS)
@@ -72,7 +70,8 @@ do_archive_push(char *wal_file_path, char *wal_file_name)
 		is_compress = IsXLogFileName(wal_file_name);
 #endif
 
-	push_wal_file(absolute_wal_file_path, backup_wal_file_path, is_compress);
+	push_wal_file(absolute_wal_file_path, backup_wal_file_path, is_compress,
+				  overwrite);
 	elog(INFO, "pg_probackup archive-push completed successfully");
 
 	return 0;

src/backup.c

@@ -1867,22 +1867,6 @@ checkpoint_timeout(void)
 	return val_int;
 }
 
-/*
- * Return true if the path is a existing regular file.
- */
-bool
-fileExists(const char *path)
-{
-	struct stat buf;
-
-	if (stat(path, &buf) == -1 && errno == ENOENT)
-		return false;
-	else if (!S_ISREG(buf.st_mode))
-		return false;
-	else
-		return true;
-}
-
 /*
  * Notify end of backup to server when "backup_label" is in the root directory
  * of the DB cluster.

src/data.c

@@ -758,7 +758,8 @@ copy_meta(const char *from_path, const char *to_path, bool unlink_on_error)
  * Copy WAL segment from pgdata to archive catalog with possible compression.
  */
 void
-push_wal_file(const char *from_path, const char *to_path, bool is_compress)
+push_wal_file(const char *from_path, const char *to_path, bool is_compress,
+			  bool overwrite)
 {
 	FILE	   *in = NULL;
 	FILE	   *out;
@@ -781,6 +782,10 @@ push_wal_file(const char *from_path, const char *to_path, bool is_compress)
 	if (is_compress)
 	{
 		snprintf(gz_to_path, sizeof(gz_to_path), "%s.gz", to_path);
+
+		if (!overwrite && fileExists(gz_to_path))
+			elog(ERROR, "WAL segment \"%s\" already exists.", gz_to_path);
+
 		gz_out = gzopen(gz_to_path, "wb");
 		if (gzsetparams(gz_out, compress_level, Z_DEFAULT_STRATEGY) != Z_OK)
 			elog(ERROR, "Cannot set compression level %d to file \"%s\": %s",
@@ -791,6 +796,9 @@ push_wal_file(const char *from_path, const char *to_path, bool is_compress)
 	else
 #endif
 	{
+		if (!overwrite && fileExists(to_path))
+			elog(ERROR, "WAL segment \"%s\" already exists.", to_path);
+
 		out = fopen(to_path, "w");
 		if (out == NULL)
 			elog(ERROR, "Cannot open destination WAL file \"%s\": %s",

src/dir.c

@@ -80,7 +80,6 @@ static char *pgdata_exclude_files[] =
 	NULL
 };
 
-pgFile *pgFileNew(const char *path, bool omit_symlink);
 static int BlackListCompare(const void *str1, const void *str2);
 
 static void dir_list_file_internal(parray *files, const char *root,
@@ -947,3 +946,19 @@ dir_is_empty(const char *path)
 
 	return true;
 }
+
+/*
+ * Return true if the path is a existing regular file.
+ */
+bool
+fileExists(const char *path)
+{
+	struct stat buf;
+
+	if (stat(path, &buf) == -1 && errno == ENOENT)
+		return false;
+	else if (!S_ISREG(buf.st_mode))
+		return false;
+	else
+		return true;
+}

src/help.c

@@ -127,6 +127,7 @@ help_pg_probackup(void)
 	printf(_("                 --wal-file-path=wal-file-path\n"));
 	printf(_("                 --wal-file-name=wal-file-name\n"));
 	printf(_("                 [--compress [--compress-level=compress-level]]\n"));
+	printf(_("                 [--overwrite]\n"));
 
 	printf(_("\n  %s archive-get -B backup-dir --instance=instance_name\n"), PROGRAM_NAME);
 	printf(_("                 --wal-file-path=wal-file-path\n"));
@@ -365,6 +366,7 @@ help_archive_push(void)
 	printf(_("                 --wal-file-path=wal-file-path\n"));
 	printf(_("                 --wal-file-name=wal-file-name\n"));
 	printf(_("                 [--compress [--compress-level=compress-level]]\n\n"));
+	printf(_("                 [--overwrite]\n"));
 
 	printf(_("  -B, --backup-path=backup-path    location of the backup storage area\n"));
 	printf(_("      --instance=instance_name     name of the instance to delete\n"));
@@ -375,6 +377,7 @@ help_archive_push(void)
 	printf(_("      --compress                   compress WAL file during archiving\n"));
 	printf(_("      --compress-level=compress-level\n"));
 	printf(_("                                   level of compression [0-9]\n"));
+	printf(_("      --overwrite                  overwrite archived WAL file\n"));
 }
 
 static void

src/pg_probackup.c

@@ -85,6 +85,7 @@ uint64		system_identifier = 0;
 /* archive push options */
 static char *wal_file_path;
 static char *wal_file_name;
+static bool	file_overwrite = false;
 
 /* current settings */
 pgBackup	current;
@@ -161,6 +162,7 @@ static pgut_option options[] =
 	/* archive-push options */
 	{ 's', 160, "wal-file-path",		&wal_file_path,		SOURCE_CMDLINE },
 	{ 's', 161, "wal-file-name",		&wal_file_name,		SOURCE_CMDLINE },
+	{ 'b', 162, "overwrite",			&file_overwrite,	SOURCE_CMDLINE },
 	{ 0 }
 };
 
@@ -410,7 +412,7 @@ main(int argc, char *argv[])
 	switch (backup_subcmd)
 	{
 		case ARCHIVE_PUSH:
-			return do_archive_push(wal_file_path, wal_file_name);
+			return do_archive_push(wal_file_path, wal_file_name, file_overwrite);
 		case ARCHIVE_GET:
 			return do_archive_get(wal_file_path, wal_file_name);
 		case ADD_INSTANCE:

src/pg_probackup.h

@@ -316,7 +316,6 @@ extern const char *pgdata_exclude_dir[];
 extern int do_backup(time_t start_time);
 extern BackupMode parse_backup_mode(const char *value);
 extern const char *deparse_backup_mode(BackupMode mode);
-extern bool fileExists(const char *path);
 extern void process_block_change(ForkNumber forknum, RelFileNode rnode,
 								 BlockNumber blkno);
 
@@ -343,7 +342,8 @@ extern int do_init(void);
 extern int do_add_instance(void);
 
 /* in archive.c */
-extern int do_archive_push(char *wal_file_path, char *wal_file_name);
+extern int do_archive_push(char *wal_file_path, char *wal_file_name,
+						   bool overwrite);
 extern int do_archive_get(char *wal_file_path, char *wal_file_name);
 
 
@@ -409,6 +409,8 @@ extern parray *dir_read_file_list(const char *root, const char *file_txt);
 extern int dir_create_dir(const char *path, mode_t mode);
 extern bool dir_is_empty(const char *path);
 
+extern bool fileExists(const char *path);
+
 extern pgFile *pgFileNew(const char *path, bool omit_symlink);
 extern pgFile *pgFileInit(const char *path);
 extern void pgFileDelete(pgFile *file);
@@ -428,7 +430,7 @@ extern void restore_data_file(const char *from_root, const char *to_root,
 extern bool copy_file(const char *from_root, const char *to_root,
 					  pgFile *file);
 extern void push_wal_file(const char *from_path, const char *to_path,
-						  bool is_compress);
+						  bool is_compress, bool overwrite);
 extern void get_wal_file(const char *from_path, const char *to_path);
 
 extern bool calc_file_checksum(pgFile *file);