?

?Rails下cloud datastore的使用

背景

部門有一個項目要用Ruby做 WebAPI，DB使用關系型數據庫Cloud Sql和非關系型數據庫Cloud Datastore 。

還不了解Ruby On Rails和CloudDatastore的請參考下面的鏈接。

http://guides.ruby-china.org/

https://thinkit.co.jp/story/2015/02/05/5594

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1、 Windows下開發環境構建

1.1、構建Ruby On Rails 開發環境

① Ruby安裝

http://www.runoob.com/ruby/ruby-installation-windows.html

② Rail安裝

從CMD提示窗口輸入指令：gem install rails 開始安裝rails。

注意：在中國直接安裝會提示錯誤，因為gem默認的安裝源https://rubygems.org在國內不能訪問，還好先輩們早已為我們新搭建了一個gem安裝源http://gems.ruby-china.org。下面是切換安裝源的具體步驟，gem安裝源切換之后，Rails安裝就可以順利進行了。

第一步：刪除默認安裝源

CMD提示窗中輸入”gem sources -remove https://rubygems.org/”，回車換行。

第二步：添加新的安裝源

CMD提示窗輸入“gem sources -add? http://gems.ruby-china.org/”，回車換行。

③ ruby的IDE Ruby Mine安裝

http://qiita.com/HALU5071/items/6d6a39e44865d8d04de8

1.2、搭建開發用Cloud Datastore 數據庫

① 安裝Google Cloud SDK

http://www.apps-gcp.com/google-cloud-sdk-install

② 安裝cloud-datastore-emulator

CMD提示窗中輸入“gcloud components install cloud-datastore-emulator”，回車換行。

③ 創建一個開發用的DB:dev_datastore

CMD提示窗中輸入“cloud_datastore_emulator create db/dev_datastore”,回車換行。

前提條件：CMD當前運行目錄下要先創建一個db的文件夾。

創建好的DB文件結構圖如下：

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2、 WEB API工程創建

在CMD提示窗中輸入“rails new my-first-api --api”，回車換行。

創建好的API工程結構見下圖，rails執行結果見附錄1。

フォルダ構造
		説明
Gemfile		gemの依存関係を指定できるファイル
README.rdoc		説明書
Rakefile	ターミナルから実行可能なタスク
config.ru		Rackの設定
app/		アプリケーションを格納するディレクトリ
		主要なプログラムはこの配下に格納
	controllers/	コントローラを格納するディレクトリ
	controllers/application_controller.rb	アプリケーションで共通のコントローラ
	models/	モデルを格納するディレクトリ
config/		プロジェクトの設定ファイルを格納するディレクトリ
config/environments/		環境単位の設定ファイルを格納するディレクトリ
config/initializers/		初期化ファイルを格納するディレクトリ
config/locales/		辭書ファイルを格納するディレクトリ
db/		データベースの設定ファイルを格納するディレクトリ
doc/		ドキュメントを格納するディレクトリ
lib/		複數のアプリケーション間で共有するライブラリを格納するディレクトリ
	tasks/	自分で生成したRakefileを格納するディレクトリ
log/		ログファイルが格納されるディレクトリ。ログファイルはアプリケーションと環境ごとに作成される
public/		Web上に公開するファイルを格納するディレクトリ
tmp/		キャッシュなど、一時的なファイルを格納されるディレクトリ
test/		アプリケーションのテストに使うファイルを格納するディレクトリ
vendor/		ライブラリや他のアプリケーションで共有するような外部ライブラリを格納するディレクトリ

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在附錄1的最后我們看到，bundle install 并沒有成功。原因是項目的gem安裝源出了問題。打開Gemfile把第一行的source 'https://rubygems.org'替換成source 'http://gems.ruby-china.org'。然后在CMD里重新執行bundle install命令，這樣項目需要的gem就能成功安裝。

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3、 新建cloud Datastore 的dataset對象

① Gem安裝

在Gemfile 中追加

gem 'google-cloud-datastore'

cmd里重新執行bundle install命令。

② 配置文件

在config/initializers/目錄下新建cloud_datastore.rb文件，文件內容如下圖所示。

從圖中我們可以看到cloud datastore 配置了三種環境下創建daset的參數，這些參數我們都放在了config/database.yml里。下面是database.yml里開發環境的配置信息，datastore 安裝的主機和datastore的數據庫名，這樣我們就可以使用datastore了。

development:
????????host: 'localhost:8180'
????????project: ' dev_datastore '

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cloud_datastore.rb

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4、 非關系型數據庫 中ActiveModel 的使用

如果我們想要cloud datastore和關系型數據庫一樣，可以方便快捷使用model（ActiveModel），怎么辦？下面就是你想要的答案。

① 追加文件

在config/initializers/目錄下新建active_model_cloud_datastore.rb文件。

文件內容參照附錄2。

② model Class寫法

require_relative "../../config/initializers/active_model_cloud_datastore" class Customer
include ActiveModelCloudDatastore
attr_accessor :customer_code, :customer_name

def attributes
%w(code customer_name)# 注意多個字段之間是半角空格來區分的
end end

這樣我們就可以使用activeModel很多功能，

#檢索所有數據

@customers = Customer.all

#保存一條新的數據

@customer = Customer.new

@customer.save

這里就不做詳細說明，具體參照附錄2里的各種方法。

5、 spec測試

1.? ?

2.? ?

3.? ?

4.? ?

5.? ?

① 測試環境安裝

在Gemfile中追加下面的gem。

group :development, :test do
# Test
gem 'rspec-rails', '~> 3.0'
gem 'rails-controller-testing'
end

然后在cmd工程目錄my-first-api下執行bundle install，安裝追加的gem。

② 測試環境初期化

在cmd工程目錄my-first-api下執行

bundle exec rails generate rspec:install

會生成下面的文件

create? .rspec create? spec create? spec/spec_helper.rb create? spec/rails_helper.rb

③ controller測試

參考下面鏈接

http://qiita.com/shizuma/items/84e07e558abd6593df15

http://blog.naichilab.com/entry/2016/01/19/011514

④ model測試

參考下面的測試思路。

http://qiita.com/shizuma/items/c7b8d7b91e8f325f8ad9

⑤ Mock使用

參考下面鏈接

http://qiita.com/jnchito/items/640f17e124ab263a54dd

6、 測試覆蓋率報告

① ?環境搭建

在Gemfile中追加下面的gem。

group :development, :test do
gem 'simplecov'
end

然后在cmd工程目錄my-first-api下執行bundle install，安裝追加的gem。

② spec_helper.rb修改

在spec_helper.rb頭部插入下面的語句，覆蓋率測試中要過濾掉spec下的測試代碼。

require 'simplecov'
SimpleCov.start do
add_filter "/spec/ "
end

③ 查看報告

在cmd工程目錄my-first-api下，再次執行rspec spec命令，覆蓋率報告就會自動生成再demo/coverage下，用google chrome瀏覽器打開index.html，就可以看到詳細的信息。下面是一個覆蓋率報告的截圖。

7、 結束語

上面我們講述的是Ruby下怎么使用cloud datastore的開發和測試，在Google Cloud Platform上怎么部署產品還有待下一步探索。期間遇到的各種技術問題難題，為了解決這些問題，調查的網站以日語和英語為主，總結的時候也使用了很多日語網站，由于時間有限，沒能一一翻譯過來，給不懂日語的朋友帶來不少困難表示歉意。

附錄1

API工程創建文件list

create

create? README.md

create? Rakefile

create? config.ru

create? .gitignore

create? Gemfile

create? app

create? app/assets/config/manifest.js

create? app/assets/javascripts/application.js

create? app/assets/javascripts/cable.js

create? app/assets/stylesheets/application.css

create? app/channels/application_cable/channel.rb

create? app/channels/application_cable/connection.rb

create? app/controllers/application_controller.rb

create? app/helpers/application_helper.rb

create? app/jobs/application_job.rb

create? app/mailers/application_mailer.rb

create? app/models/application_record.rb

create? app/views/layouts/application.html.erb

create? app/views/layouts/mailer.html.erb

create? app/views/layouts/mailer.text.erb

create? app/assets/images/.keep

create? app/assets/javascripts/channels

create? app/assets/javascripts/channels/.keep

create? app/controllers/concerns/.keep

create? app/models/concerns/.keep

create? bin

create? bin/bundle

create? bin/rails

create? bin/rake

create? bin/setup

create? bin/update

create? config

create? config/routes.rb

create? config/application.rb

create? config/environment.rb

create? config/secrets.yml

create? config/cable.yml

create? config/puma.rb

create? config/environments

create? config/environments/development.rb

create? config/environments/production.rb

create? config/environments/test.rb

create? config/initializers

create? config/initializers/application_controller_renderer.rb

create? config/initializers/assets.rb

create? config/initializers/backtrace_silencers.rb

create? config/initializers/cookies_serializer.rb

create? config/initializers/cors.rb

create? config/initializers/filter_parameter_logging.rb

create? config/initializers/inflections.rb

create? config/initializers/mime_types.rb

create? config/initializers/new_framework_defaults.rb

create? config/initializers/session_store.rb

create? config/initializers/wrap_parameters.rb

create? config/locales

create? config/locales/en.yml

create? config/boot.rb

create? config/database.yml

create? db

create? db/seeds.rb

create? lib

create? lib/tasks

create? lib/tasks/.keep

create? lib/assets

create? lib/assets/.keep

create? log

create? log/.keep

create? public

create? public/404.html

create? public/422.html

create? public/500.html

create? public/apple-touch-icon-precomposed.png

create? public/apple-touch-icon.png

create? public/favicon.ico

create? public/robots.txt

create? test/fixtures

create? test/fixtures/.keep

create? test/fixtures/files

create? test/fixtures/files/.keep

create? test/controllers

create? test/controllers/.keep

create? test/mailers

create? test/mailers/.keep

create? test/models

create? test/models/.keep

create? test/helpers

create? test/helpers/.keep

create? test/integration

create? test/integration/.keep

create? test/test_helper.rb

create? tmp

create? tmp/.keep

create? tmp/cache

create? tmp/cache/assets

create? vendor/assets/stylesheets

create? vendor/assets/stylesheets/.keep

remove? app/assets

remove? lib/assets

remove? tmp/cache/assets

remove? vendor/assets

remove? app/helpers

remove? test/helpers

remove? app/views/layouts/application.html.erb

remove? public/404.html

remove? public/422.html

remove? public/500.html

remove? public/apple-touch-icon-precomposed.png

remove? public/apple-touch-icon.png

remove? public/favicon.ico

remove? app/assets/javascripts

remove? config/initializers/assets.rb

remove? config/initializers/session_store.rb

remove? config/initializers/cookies_serializer.rb

Fetching gem metadata from https://rubygems.org/..........

Fetching version metadata from https://rubygems.org/..

Fetching dependency metadata from https://rubygems.org/.

Resolving dependencies...

Using rake 12.0.0

Using i18n 0.7.0

Using minitest 5.10.1

Using thread_safe 0.3.5

Using builder 3.2.2

Using erubis 2.7.0

Using mini_portile2 2.1.0

Using rack 2.0.1

Using nio4r 1.2.1

Using websocket-extensions 0.1.2

Using mime-types-data 3.2016.0521

Using arel 7.1.4

Using bundler 1.13.6

Using method_source 0.8.2

Using puma 3.6.2

Using thor 0.19.4

Using sqlite3 1.3.12

Gem::RemoteFetcher::FetchError: SSL_connect returned=1 errno=0 state=SSLv3 read

server certificate B: certificate verify failed

(https://rubygems.org/gems/concurrent-ruby-1.0.4.gem)

An error occurred while installing concurrent-ruby (1.0.4), and Bundler cannot

continue.

Make sure that `gem install concurrent-ruby -v '1.0.4'` succeeds before

bundling.

附錄2

active_model_cloud_datastore.rb文件內容：

# frozen_string_literal: true

require_relative 'cloud_datastore'
require 'active_model'
require 'active_support'


# Integrates ActiveModel with the Google::Cloud::Datastore
module ActiveModelCloudDatastore
extend ActiveSupport::Concern
include ActiveModel::Model
include ActiveModel::Dirty
include ActiveModel::Validations
include ActiveModel::Validations::Callbacks

included do
private_class_method :query_options, :query_sort, :query_property_filter
define_model_callbacks :save, :update, :destroy
attr_accessor :id
end

def attributes
[]
end

# Used by ActiveModel for determining polymorphic routing.
def persisted?
id.present?
end

# Resets the ActiveModel::Dirty tracked changes
def reload!
clear_changes_information
end

# Updates attribute values on the ActiveModel::Model object with the provided params.
# Example, such as submitted form params.
#
# @param [Hash] params
def update_model_attributes(params)
params.each do |name, value|
send "#{name}=", value if respond_to? "#{name}="
end
end

# Builds the Cloud Datastore entity with attributes from the Model object.
#
# @return [Entity] the updated Google::Cloud::Datastore::Entity
def build_entity(parent = nil)
entity = CloudDatastore.dataset.entity(self.class.name, id)
entity.key.parent = parent if parent
attributes.each do |attr|
entity[attr] = instance_variable_get("@#{attr}")
end
entity
end

def save(parent = nil)
run_callbacks :save do
if valid?
entity = build_entity(parent)
success = self.class.retry_on_exception? { CloudDatastore.dataset.save(entity) }
if success
self.id = entity.key.id
return true
end
end
false
end
end

def update(params)
run_callbacks :update do
update_model_attributes(params)
if valid?
entity = build_entity
self.class.retry_on_exception? { CloudDatastore.dataset.save(entity) }
else
false
end
end
end

def destroy
run_callbacks :destroy do
key = CloudDatastore.dataset.key(self.class.name, id)
self.class.retry_on_exception? { CloudDatastore.dataset.delete(key) }
end
end

# Methods defined here will be class methods whenever we 'include DatastoreUtils'.
module ClassMethods
# Queries all objects from Cloud Datastore by named kind and using the provided options.
#
# @param [Hash] options the options to construct the query with.
#
# @option options [Google::Cloud::Datastore::Key] :ancestor filter for inherited results
# @option options [Hash] :where filter, Array in the format [name, operator, value]
#
# @return [Array<Model>] an array of ActiveModel results.
def all(options = {})
query = CloudDatastore.dataset.query(name)
query.ancestor(options[:ancestor]) if options[:ancestor]
query_property_filter(query, options)
entities = retry_on_exception { CloudDatastore.dataset.run(query) }
from_entities(entities.flatten)
end

# Queries objects from Cloud Datastore in batches by named kind and using the provided options.
# When a limit option is provided queries up to the limit and returns results with a cursor.
#
# @param [Hash] options the options to construct the query with. See build_query for options.
#
# @return [Array<Model>, String] an array of ActiveModel results and a cursor that can be used
# to query for additional results.
def find_in_batches(options = {})
next_cursor = nil
query = build_query(options)
if options[:limit]
entities = retry_on_exception { CloudDatastore.dataset.run(query) }
next_cursor = entities.cursor if entities.size == options[:limit]
else
entities = retry_on_exception { CloudDatastore.dataset.run(query) }
end
model_entities = from_entities(entities.flatten)
return model_entities, next_cursor
end

# Retrieves an entity by key and by an optional parent.
#
# @param [Integer or String] id_or_name id or name value of the entity Key.
# @param [Google::Cloud::Datastore::Key] parent the parent Key of the entity.
#
# @return [Entity, nil] a Google::Cloud::Datastore::Entity object or nil.
def find_entity(id_or_name, parent = nil)
key = CloudDatastore.dataset.key(name, id_or_name)
key.parent = parent if parent
retry_on_exception { CloudDatastore.dataset.find(key) }
end

# Find object by ID.
#
# @return [Model, nil] an ActiveModel object or nil.
def find(id)
entity = find_entity(id.to_i)
from_entity(entity)
end

# Find object by parent and ID.
#
# @return [Model, nil] an ActiveModel object or nil.
def find_by_parent(id, parent)
entity = find_entity(id.to_i, parent)
from_entity(entity)
end

def from_entities(entities)
entities.map { |entity| from_entity(entity) }
end

# Translates between Google::Cloud::Datastore::Entity objects and ActiveModel::Model objects.
#
# @param [Entity] entity from Cloud Datastore
# @return [Model] the translated ActiveModel object.
def from_entity(entity)
return if entity.nil?
model_entity = new
model_entity.id = entity.key.id unless entity.key.id.nil?
model_entity.id = entity.key.name unless entity.key.name.nil?
entity.properties.to_hash.each do |name, value|
model_entity.send "#{name}=", value
end
model_entity.reload!
model_entity
end

def exclude_from_index(entity, boolean)
entity.properties.to_h.keys.each do |value|
entity.exclude_from_indexes! value, boolean
end
end

# Constructs a Google::Cloud::Datastore::Query.
#
# @param [Hash] options the options to construct the query with.
#
# @option options [Google::Cloud::Datastore::Key] :ancestor filter for inherited results
# @option options [String] :cursor sets the cursor to start the results at
# @option options [Integer] :limit sets a limit to the number of results to be returned
# @option options [String] :order sort the results by property name
# @option options [String] :desc_order sort the results by descending property name
# @option options [Array] :select retrieve only select properties from the matched entities
# @option options [Hash] :where filter, Array in the format [name, operator, value]
#
# @return [Query] a datastore query.
def build_query(options = {})
query = CloudDatastore.dataset.query(name)
query_options(query, options)
end

def retry_on_exception?
retry_count = 0
sleep_time = 0.5 # 0.5, 1, 2, 4 second between retries
begin
yield
rescue => e
puts "\e[33m[#{e.message.inspect}]\e[0m"
puts 'Rescued exception, retrying...'
sleep sleep_time
sleep_time *= 2
retry_count += 1
return false if retry_count > 3
retry
end
true
end

def retry_on_exception
retry_count = 0
sleep_time = 0.5 # 0.5, 1, 2, 4 second between retries
begin
yield
rescue => e
puts "\e[33m[#{e.message.inspect}]\e[0m"
puts 'Rescued exception, retrying...'
sleep sleep_time
sleep_time *= 2
retry_count += 1
raise e if retry_count > 3
retry
end
end

def log_google_cloud_error
yield
rescue Google::Cloud::Error => e
puts "\e[33m[#{e.message.inspect}]\e[0m"
raise e
end

# private

def query_options(query, options)
query.ancestor(options[:ancestor]) if options[:ancestor]
query.cursor(options[:cursor]) if options[:cursor]
query.limit(options[:limit]) if options[:limit]
query_sort(query, options)
query.select(options[:select]) if options[:select]
query_property_filter(query, options)
end

# Adds sorting to the results by a property name if included in the options.
def query_sort(query, options)
query.order(options[:order]) if options[:order]
query.order(options[:desc_order], :desc) if options[:desc_order]
query
end

# Adds property filters to the query if included in the options.
# Accepts individual or nested Arrays:
# [['superseded', '=', false], ['email', '=', 'something']]
def query_property_filter(query, options)
if options[:where]
opts = options[:where]
if opts[0].is_a?(Array)
opts.each do |opt|
query.where(opt[0], opt[1], opt[2]) unless opt.nil?
end
else
query.where(opts[0], opts[1], opts[2])
end
end
query
end
end
end

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轉載于:https://www.cnblogs.com/sundongxiang/p/6237805.html

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