mirror of
https://github.com/octoleo/restic.git
synced 2024-12-11 13:52:31 +00:00
149 lines
4.3 KiB
Plaintext
149 lines
4.3 KiB
Plaintext
|
// Copyright 2017 Google Inc. All Rights Reserved.
|
||
|
//
|
||
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
// you may not use this file except in compliance with the License.
|
||
|
// You may obtain a copy of the License at
|
||
|
//
|
||
|
// http://www.apache.org/licenses/LICENSE-2.0
|
||
|
//
|
||
|
// Unless required by applicable law or agreed to in writing, software
|
||
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
// See the License for the specific language governing permissions and
|
||
|
// limitations under the License.
|
||
|
|
||
|
// DO NOT EDIT doc.go. Modify internal/doc.template, then run make -C internal.
|
||
|
|
||
|
/*
|
||
|
Package firestore provides a client for reading and writing to a Cloud Firestore
|
||
|
database.
|
||
|
|
||
|
See https://cloud.google.com/firestore/docs for an introduction
|
||
|
to Cloud Firestore and additional help on using the Firestore API.
|
||
|
|
||
|
Creating a Client
|
||
|
|
||
|
To start working with this package, create a client with a project ID:
|
||
|
|
||
|
[NewClient]
|
||
|
|
||
|
CollectionRefs and DocumentRefs
|
||
|
|
||
|
In Firestore, documents are sets of key-value pairs, and collections are groups of
|
||
|
documents. A Firestore database consists of a hierarchy of alternating collections
|
||
|
and documents, referred to by slash-separated paths like
|
||
|
"States/California/Cities/SanFrancisco".
|
||
|
|
||
|
This client is built around references to collections and documents. CollectionRefs
|
||
|
and DocumentRefs are lightweight values that refer to the corresponding database
|
||
|
entities. Creating a ref does not involve any network traffic.
|
||
|
|
||
|
[refs]
|
||
|
|
||
|
Reading
|
||
|
|
||
|
Use DocumentRef.Get to read a document. The result is a DocumentSnapshot.
|
||
|
Call its Data method to obtain the entire document contents as a map.
|
||
|
|
||
|
[docref.Get]
|
||
|
|
||
|
You can also obtain a single field with DataAt, or extract the data into a struct
|
||
|
with DataTo. With the type definition
|
||
|
|
||
|
[structDef]
|
||
|
|
||
|
we can extract the document's data into a value of type State:
|
||
|
|
||
|
[DataTo]
|
||
|
|
||
|
Note that this client supports struct tags beginning with "firestore:" that work like
|
||
|
the tags of the encoding/json package, letting you rename fields, ignore them, or
|
||
|
omit their values when empty.
|
||
|
|
||
|
To retrieve multiple documents from their references in a single call, use
|
||
|
Client.GetAll.
|
||
|
|
||
|
[GetAll]
|
||
|
|
||
|
Writing
|
||
|
|
||
|
For writing individual documents, use the methods on DocumentReference.
|
||
|
Create creates a new document.
|
||
|
|
||
|
[docref.Create]
|
||
|
|
||
|
The first return value is a WriteResult, which contains the time
|
||
|
at which the document was updated.
|
||
|
|
||
|
Create fails if the document exists. Another method, Set, either replaces an existing
|
||
|
document or creates a new one.
|
||
|
|
||
|
[docref.Set]
|
||
|
|
||
|
To update some fields of an existing document, use UpdateMap, UpdateStruct or
|
||
|
UpdatePaths. For UpdateMap, the keys of the map specify which fields to change. The
|
||
|
others are untouched.
|
||
|
|
||
|
[docref.UpdateMap]
|
||
|
|
||
|
For UpdateStruct, you must explicitly provide the fields to update. The field names
|
||
|
must match exactly.
|
||
|
|
||
|
[docref.UpdateStruct]
|
||
|
|
||
|
Use DocumentRef.Delete to delete a document.
|
||
|
|
||
|
[docref.Delete]
|
||
|
|
||
|
Preconditions
|
||
|
|
||
|
You can condition Deletes or Updates on when a document was last changed. Specify
|
||
|
these preconditions as an option to a Delete or Update method. The check and the
|
||
|
write happen atomically with a single RPC.
|
||
|
|
||
|
[LUT-precond]
|
||
|
|
||
|
Here we update a doc only if it hasn't changed since we read it.
|
||
|
You could also do this with a transaction.
|
||
|
|
||
|
To perform multiple writes at once, use a WriteBatch. Its methods chain
|
||
|
for convenience.
|
||
|
|
||
|
WriteBatch.Commit sends the collected writes to the server, where they happen
|
||
|
atomically.
|
||
|
|
||
|
[WriteBatch]
|
||
|
|
||
|
Queries
|
||
|
|
||
|
You can use SQL to select documents from a collection. Begin with the collection, and
|
||
|
build up a query using Select, Where and other methods of Query.
|
||
|
|
||
|
[Query]
|
||
|
|
||
|
Call the Query's Documents method to get an iterator, and use it like
|
||
|
the other Google Cloud Client iterators.
|
||
|
|
||
|
[Documents]
|
||
|
|
||
|
To get all the documents in a collection, you can use the collection itself
|
||
|
as a query.
|
||
|
|
||
|
[CollQuery]
|
||
|
|
||
|
Transactions
|
||
|
|
||
|
Use a transaction to execute reads and writes atomically. All reads must happen
|
||
|
before any writes. Transaction creation, commit, rollback and retry are handled for
|
||
|
you by the Client.RunTransaction method; just provide a function and use the
|
||
|
read and write methods of the Transaction passed to it.
|
||
|
|
||
|
[Transaction]
|
||
|
|
||
|
Authentication
|
||
|
|
||
|
See examples of authorization and authentication at
|
||
|
https://godoc.org/cloud.google.com/go#pkg-examples.
|
||
|
*/
|
||
|
package firestore
|