1 files changed, 144 insertions, 0 deletions
diff --git a/src/pybind/mgr/volumes/fs/operations/versions/metadata_manager.py b/src/pybind/mgr/volumes/fs/operations/versions/metadata_manager.py
new file mode 100644
index 00000000..1b6c4327
--- /dev/null
+++ b/src/pybind/mgr/volumes/fs/operations/versions/metadata_manager.py
@@ -0,0 +1,144 @@
+import os
+import errno
+import logging
+import sys
+
+if sys.version_info >= (3, 2):
+    import configparser
+else:
+    import ConfigParser as configparser
+
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
+
+import cephfs
+
+from ...exception import MetadataMgrException
+
+log = logging.getLogger(__name__)
+
+class MetadataManager(object):
+    GLOBAL_SECTION = "GLOBAL"
+    GLOBAL_META_KEY_VERSION = "version"
+    GLOBAL_META_KEY_TYPE    = "type"
+    GLOBAL_META_KEY_PATH    = "path"
+    GLOBAL_META_KEY_STATE   = "state"
+
+    MAX_IO_BYTES = 8 * 1024
+
+    def __init__(self, fs, config_path, mode):
+        self.fs = fs
+        self.mode = mode
+        self.config_path = config_path
+        if sys.version_info >= (3, 2):
+            self.config = configparser.ConfigParser()
+        else:
+            self.config = configparser.SafeConfigParser()
+
+    def refresh(self):
+        fd = None
+        conf_data = StringIO()
+        try:
+            log.debug("opening config {0}".format(self.config_path))
+            fd = self.fs.open(self.config_path, os.O_RDONLY)
+            while True:
+                data = self.fs.read(fd, -1, MetadataManager.MAX_IO_BYTES)
+                if not len(data):
+                    break
+                conf_data.write(data.decode('utf-8'))
+            conf_data.seek(0)
+            self.config.readfp(conf_data)
+        except cephfs.ObjectNotFound:
+            raise MetadataMgrException(-errno.ENOENT, "metadata config '{0}' not found".format(self.config_path))
+        except cephfs.Error as e:
+            raise MetadataMgrException(-e.args[0], e.args[1])
+        finally:
+            if fd is not None:
+                self.fs.close(fd)
+
+    def flush(self):
+        # cull empty sections
+        for section in list(self.config.sections()):
+            if len(self.config.items(section)) == 0:
+                self.config.remove_section(section)
+
+        conf_data = StringIO()
+        self.config.write(conf_data)
+        conf_data.seek(0)
+
+        fd = None
+        try:
+            fd = self.fs.open(self.config_path, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, self.mode)
+            wrote = 0
+            while True:
+                data = conf_data.read()
+                if not len(data):
+                    break
+                wrote += self.fs.write(fd, data.encode('utf-8'), -1)
+            self.fs.fsync(fd, 0)
+            log.info("wrote {0} bytes to config {1}".format(wrote, self.config_path))
+        except cephfs.Error as e:
+            raise MetadataMgrException(-e.args[0], e.args[1])
+        finally:
+            if fd is not None:
+                self.fs.close(fd)
+
+    def init(self, version, typ, path, state):
+        # you may init just once before refresh (helps to overwrite conf)
+        if self.config.has_section(MetadataManager.GLOBAL_SECTION):
+            raise MetadataMgrException(-errno.EINVAL, "init called on an existing config")
+
+        self.add_section(MetadataManager.GLOBAL_SECTION)
+        self.update_section_multi(
+            MetadataManager.GLOBAL_SECTION, {MetadataManager.GLOBAL_META_KEY_VERSION : str(version),
+                                             MetadataManager.GLOBAL_META_KEY_TYPE    : str(typ),
+                                             MetadataManager.GLOBAL_META_KEY_PATH    : str(path),
+                                             MetadataManager.GLOBAL_META_KEY_STATE   : str(state)
+            })
+
+    def add_section(self, section):
+        try:
+            self.config.add_section(section)
+        except configparser.DuplicateSectionError:
+            return
+        except:
+            raise MetadataMgrException(-errno.EINVAL, "error adding section to config")
+
+    def remove_option(self, section, key):
+        if not self.config.has_section(section):
+            raise MetadataMgrException(-errno.ENOENT, "section '{0}' does not exist".format(section))
+        self.config.remove_option(section, key)
+
+    def remove_section(self, section):
+        self.config.remove_section(section)
+
+    def update_section(self, section, key, value):
+        if not self.config.has_section(section):
+            raise MetadataMgrException(-errno.ENOENT, "section '{0}' does not exist".format(section))
+        self.config.set(section, key, str(value))
+
+    def update_section_multi(self, section, dct):
+        if not self.config.has_section(section):
+            raise MetadataMgrException(-errno.ENOENT, "section '{0}' does not exist".format(section))
+        for key,value in dct.items():
+            self.config.set(section, key, str(value))
+
+    def update_global_section(self, key, value):
+        self.update_section(MetadataManager.GLOBAL_SECTION, key, str(value))
+
+    def get_option(self, section, key):
+        if not self.config.has_section(section):
+            raise MetadataMgrException(-errno.ENOENT, "section '{0}' does not exist".format(section))
+        if not self.config.has_option(section, key):
+            raise MetadataMgrException(-errno.ENOENT, "no config '{0}' in section '{1}'".format(key, section))
+        return self.config.get(section, key)
+
+    def get_global_option(self, key):
+        return self.get_option(MetadataManager.GLOBAL_SECTION, key)
+
+    def section_has_item(self, section, item):
+        if not self.config.has_section(section):
+            raise MetadataMgrException(-errno.ENOENT, "section '{0}' does not exist".format(section))
+        return item in [v[1] for v in self.config.items(section)]