Source code for thoth.storages.ceph

#!/usr/bin/env python3
# thoth-storages
# Copyright(C) 2018, 2019, 2020 Fridolin Pokorny
#
# This program is free software: you can redistribute it and / or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

"""Adapter for Ceph distributed object storage."""

import json
import os
import typing

import boto3
import botocore

from .base import StorageBase
from .exceptions import NotFoundError


[docs]class CephStore(StorageBase): """Adapter for storing and retrieving data from Ceph - low level API.""" def __init__( self, prefix, *, host: str = None, key_id: str = None, secret_key: str = None, bucket: str = None, region: str = None, ): """Initialize adapter to Ceph. Parameters not explicitly provided will be picked from env variables. """ super().__init__() self.host = host or os.environ["THOTH_S3_ENDPOINT_URL"] self.key_id = key_id or os.environ["THOTH_CEPH_KEY_ID"] self.secret_key = secret_key or os.environ["THOTH_CEPH_SECRET_KEY"] self.bucket = bucket or os.environ["THOTH_CEPH_BUCKET"] self.region = region or os.getenv("THOTH_CEPH_REGION", None) self._s3 = None self.prefix = prefix if not self.prefix.endswith("/"): self.prefix += "/"
[docs] def get_document_listing(self, prefix_addition: typing.Optional[str] = None) -> typing.Generator[str, None, None]: """Get listing of documents stored on the Ceph.""" prefix = f"{self.prefix}{prefix_addition}" if prefix_addition else self.prefix for obj in self._s3.Bucket(self.bucket).objects.filter(Prefix=prefix).all(): yield obj.key[len(self.prefix) :] # Ignore PycodestyleBear (E203)
[docs] def store_file(self, document_path: str, document_id: str) -> dict: """Store a file on Ceph.""" response = self._s3.Object(self.bucket, f"{self.prefix}{document_id}").upload_file(Filename=document_path) return response
[docs] @staticmethod def dict2blob(dictionary: dict) -> bytes: """Encode a dictionary to a blob so it can be stored on Ceph.""" return json.dumps(dictionary, sort_keys=True, separators=(",", ": "), indent=2).encode()
[docs] def store_blob(self, blob: bytes, object_key: str) -> dict: """Store a blob on Ceph.""" put_kwargs = {"Body": blob} response = self._s3.Object(self.bucket, f"{self.prefix}{object_key}").put(**put_kwargs) return response
[docs] def delete(self, object_key: str) -> None: """Delete the given object from Ceph.""" self._s3.Object(self.bucket, f"{self.prefix}{object_key}").delete()
[docs] def store_document(self, document: dict, document_id: str) -> dict: """Store a document (dict) onto Ceph.""" blob = self.dict2blob(document) return self.store_blob(blob, document_id)
[docs] def retrieve_blob(self, object_key: str) -> bytes: """Retrieve remote object content.""" try: return self._s3.Object(self.bucket, f"{self.prefix}{object_key}").get()["Body"].read() except botocore.exceptions.ClientError as exc: if exc.response["Error"]["Code"] in ("404", "NoSuchKey"): raise NotFoundError("Failed to retrieve object, object {!r} does not exist".format(object_key)) from exc raise
[docs] def iterate_results(self, prefix_addition: typing.Optional[str] = None) -> typing.Generator[tuple, None, None]: """Iterate over results available in the Ceph.""" for document_id in self.get_document_listing(prefix_addition=prefix_addition): document = self.retrieve_document(document_id) yield document_id, document
[docs] def retrieve_document(self, document_id: str) -> dict: """Retrieve a dictionary stored as JSON from S3.""" return json.loads(self.retrieve_blob(document_id).decode())
[docs] def is_connected(self) -> bool: """Check whether adapter is connected to the remote Ceph storage.""" return self._s3 is not None
[docs] def document_exists(self, document_id: str) -> bool: """Check if the there is an object with the given key in bucket. This check does only HEAD request. """ try: self._s3.Object(self.bucket, f"{self.prefix}{document_id}").load() except botocore.exceptions.ClientError as exc: if exc.response["Error"]["Code"] == "404": exists = False else: raise else: exists = True return exists
[docs] def check_connection(self) -> None: """Ceph Connection Check. Check whether the given connection to the Ceph is alive and healthy, raise an exception if not. """ # The document exists method calls HEAD so we do not transfer actual # data. We do not care if the given document actually really exists, # but we raise an exception if there is an issue with the connection. self.document_exists("foo")
[docs] def connect(self) -> None: """Create a connection to the remote Ceph.""" session = boto3.session.Session( aws_access_key_id=self.key_id, aws_secret_access_key=self.secret_key, region_name=self.region ) # signature version is needed to connect to new regions which # support only v4 self._s3 = session.resource( "s3", config=botocore.client.Config(signature_version="s3v4"), endpoint_url=self.host )
# Ceph returns 403 on this call, let's assume the bucket exists. # self._create_bucket_if_needed() def _create_bucket_if_needed(self) -> None: """Create desired bucket based on configuration. If the given bucket does not already exist, it is created. """ # check that the bucket exists - see boto3 docs try: self._s3.meta.client.head_bucket(Bucket=self.bucket) except botocore.exceptions.ClientError as exc: # if a client error is thrown, then check that it was a 404 error. # if it was a 404 error, then the bucket does not exist. try: error_code = int(exc.response["Error"]["Code"]) except (TypeError, ValueError, KeyError): raise if error_code == 404: self._create_bucket() else: raise def _create_bucket(self) -> None: """Create a bucket.""" # Yes boto3, you are doing it right: # https://github.com/boto/boto3/issues/125 if self.region == "us-east-1": self._s3.create_bucket(Bucket=self.bucket) else: self._s3.create_bucket(Bucket=self.bucket, CreateBucketConfiguration={"LocationConstraint": self.region})