heroku搭建mysql

By: Edward Krueger Data Scientist and Instructor and Douglas Franklin Teaching Assistant and Technical Writer.

作者： 愛德華·克魯格(Edward Krueger)數據科學家和講師， 道格拉斯·富蘭克林 ( Douglas Franklin)教學助理和技術作家。

In this article, we’ll cover how to deploy an app with a Pipfile.lock to the cloud and connect the app to a cloud database. For more information on virtual environments or getting started with the environment and package manager Pipenv, check out this article!

在本文中，我們將介紹如何將具有Pipfile.lock的應用程序部署到云上以及如何將該應用程序連接到云數據庫。 有關虛擬環境或環境和程序包管理器Pipenv入門的更多信息，請查看 本文 ！

部署問題 (Deployment Issues)

Newer developers often install everything at the system level due to a lack of understanding of, or experience with, virtual environments. Python packages installed with pip are placed at the system level. Retrieving requirements this way for every project creates an unmanageable global Python environment on your machine. Virtual environments allow you to compartmentalize your software while keeping an inventory of dependencies.

由于缺乏對虛擬環境的了解或經驗，較新的開發人員通常在系統級別安裝所有內容。 與pip一起安裝的Python軟件包位于系統級別。 以這種方式為每個項目檢索需求會在您的計算機上創建一個難以管理的全局Python環境。 虛擬環境使您可以劃分軟件，同時保留依賴性清單。

Pipenv, a tool for virtual environment and Python package management, allows developers to create isolated software products that are easier to deploy, build upon, and modify.

Pipenv是用于虛擬環境和Python軟件包管理的工具，它使開發人員能夠創建隔離的軟件產品，這些產品更易于部署，構建和修改。

什么是Pipenv？ (What is Pipenv?)

Pipenv combines package management and virtual environment control into one tool for installing, removing, tracking, and documenting your dependencies; and for creating, using, and managing your virtual environments. Pipenv is essentially pip and virtualenv wrapped together into a single product.

Pipenv將軟件包管理和虛擬環境控制結合到一個工具中，用于安裝，刪除，跟蹤和記錄依賴項。 以及用于創建，使用和管理虛擬環境。 Pipenv本質上是將pip和virtualenv打包到一個產品中。

什么是Heroku？ (What is Heroku?)

Heroku offers many software products, and we’ll need the Heroku cloud platform service to host an app and JawsDB to use a MySQL database. Don’t worry, creating an account and using these features is free!

Heroku提供了許多軟件產品，我們將需要Heroku云平臺服務來托管應用程序，而JawsDB需要使用MySQL數據庫。 不用擔心，創建帳戶和使用這些功能是免費的！

We are going to use the Heroku GUI to deploy a database and a Python app.

我們將使用Heroku GUI部署數據庫和Python應用程序。

云數據庫的好處 (Benefits of cloud database)

In our previous deployment, we used an SQLite database. When using an SQLite database, every app redeployment will reset your database. Heroku’s JawsDB allows our data to persist through app updates. Additionally, hosting, configuring, patching, and managing the database is all done for you with JawsDB.

在之前的部署中，我們使用了SQLite數據庫。 使用SQLite數據庫時，每次重新部署應用程序都會重置您的數據庫。 Heroku的JawsDB允許我們的數據通過應用程序更新保持不變。 此外，使用JawsDB可以為您完成托管，配置，修補和管理數據庫。

準備部署 (Preparing for Deployment)

Heroku allows us to deploy an app from a GitHub branch. Once we have a working app with a Pipfile pushed to GitHub, we are ready to make some final changes to the repository to prepare for deployment. Be sure to have your Pipfile at the project’s root directory so Heroku can find it!

Heroku允許我們從GitHub分支部署應用程序。 將Pipfile推送到GitHub后，我們就可以正常工作了，我們準備對存儲庫進行一些最終更改，以準備進行部署。 確保將Pipfile放在項目的根目錄下，以便Heroku可以找到它！

Note: These next changes allow our app to run on Unix systems. Gunicorn is not compatible with PCs, so you will not be able to test these changes locally if you are not using a Linux or Unix machine.

注意：接下來的這些更改使我們的應用程序可以在Unix系統上運行。 Gunicorn與PC不兼容，因此，如果您未使用Linux或Unix計算機，則將無法在本地測試這些更改。

安裝gunicorn (Install gunicorn)

Gunicorn is a Python WSGI HTTP server that will serve your Flask application on Heroku. By running the line below, you add gunicorn to your Pipfile.

Gunicorn是Python WSGI HTTP服務器，將在Heroku上為Flask應用程序提供服務。 通過運行以下行，您可以將gunicorn添加到Pipfile中。

pipenv install gunicorn

添加一個Procfile (Add a Procfile)

Create a Procfile in the project root folder and add the following line:

在項目根文件夾中創建一個Procfile并添加以下行：

web: gunicorn app:app

The first app represents the name of the python file that runs your application or the name of the module where the app is located. The second represents your app name, i.e., app.py. This Procfile works with gunicorn and Heroku's Dynos to serve your app remotely.

第一個app代表運行您的應用程序的python文件的名稱或該應用程序所在的模塊的名稱。 第二個代表您的應用名稱，即app.py。 該Procfile可與gunicorn和Heroku的Dynos一起使用，以遠程服務您的應用程序。

Heroku云數據庫的設置和部署 (Heroku Cloud Database Set up and Deployment)

Set up an account with Heroku if you haven’t already, don’t worry all the features we show here are free!

如果您尚未注冊Heroku，請不要擔心，我們在此顯示的所有功能都是免費的！

Go to your app on Heroku.com and click resources. Then type “JawsDB MySQL” into the addons box, as seen below.

轉到Heroku.com上的應用程序，然后單擊資源。 然后在插件框中鍵入“ JawsDB MySQL”，如下所示。

Select the free version and click provision. Great, we now have a MySQL database deployed for our app. Next, we need to integrate this new database into our app logic.

選擇免費版本，然后單擊設置。 太好了，我們現在為我們的應用程序部署了一個MySQL數據庫。 接下來，我們需要將此新數據庫集成到我們的應用程序邏輯中。

First, let’s add Pymysql, a Python SQL library, to our Pipfile with the following.

首先，使用以下代碼將Pymysql(Python SQL庫)添加到我們的Pipfile中。

pipenv install pymysql

Now let’s get our connection string and modify it for pymysql. Go to settings and look at the configuration variables. You’ll find a connection string that resembles the one below.

現在，讓我們獲取連接字符串并為pymysql對其進行修改。 轉到設置，然后查看配置變量。 您會發現類似于以下內容的連接字符串。

mysql://ael7qci22z1qwer:nn9keetiyertrwdf@c584asdfgjnm02sk.cbetxkdfhwsb.us-east-1.rds.amazonaws.com:3306/fq14casdf1rb3y3n

We need to make a change to the DB connection string so that it uses the Pymysql driver.

我們需要更改數據庫連接字符串，以便它使用Pymysql驅動程序。

In a text editor, remove the mysql and add in its place mysql+pymysql and then save the updated string.

在文本編輯器中，刪除mysql并在其位置添加mysql+pymysql ，然后保存更新的字符串。

mysql+pymysql

You’ll need to add this to your configuration variables on Heroku. To do this, go to settings, then config vars and update the connection string.

您需要將此添加到Heroku上的配置變量中。 為此，請轉到設置，然后配置vars并更新連接字符串。

用.env隱藏連接字符串 (Hiding connection strings with .env)

Create a new file called .env and add the connection string for your cloud database as DB_CONN,shown below.

創建一個名為.env的新文件，并將云數據庫的連接字符串添加為DB_CONN,如下所示。

DB_CONN=”mysql+pymysql://root:PASSWORD@HOSTNAME:3306/records_db”

Note: Running pipenv shell gives us access to these hidden environmental variables. Similarly, we can access the hidden variables in Python with os.

注意：運行pipenv shell使我們可以訪問這些隱藏的環境變量。 同樣，我們可以使用os訪問Python中的隱藏變量。

SQLALCHEMY_DB_URL = os.getenv(“DB_CONN”)

Be sure to add the above line to your database.py file so that it ready to connect to the cloud!

確保將以上行添加到您的database.py文件中，以便它可以連接到云！

應用部署 (App Deployment)

Once we have our app tested and working locally, we push all code to the master branch. Then on Heroku, go to deploy a new app to see the page below.

一旦我們的應用程序經過測試并在本地工作，我們便將所有代碼推送到master分支。 然后在Heroku上，部署一個新的應用程序以查看下面的頁面。

Select Github and search for your repository 選擇Github并搜索您的存儲庫

Next on Heroku, select GitHub, enter the name of the repository and hit search. Once your username and repository appear, click connect. Then select the desired branch and click deploy.

接下來在Heroku上，選擇GitHub，輸入存儲庫的名稱，然后點擊搜索。 用戶名和存儲庫出現后，單擊“連接”。 然后選擇所需的分支，然后單擊部署。

Select master and deploy the branch 選擇主節點并部署分支

Build logs will begin to populate a console on the page. Notice that Heroku looks for a requirements.txt file first then installs dependencies from Pipenv’s Pipfile.lock. If you don’t use Pipenv, you will need to have a requiremnts.txt for this build to occur. Once again, place these files at your project’s root.

構建日志將開始在頁面上填充控制臺。 請注意，Heroku首先會查找require.txt文件，然后從Pipenv的Pipfile.lock安裝依賴項。 如果您不使用Pipenv，則需要具有requiremnts.txt才能進行此構建。 再一次將這些文件放在項目的根目錄。

Once your environment has been built from the Pipfile.lock and the build is successful, you will see the below message.

從Pipfile.lock構建環境并且構建成功后，您將看到以下消息。

Successful app deployment 成功部署應用

The app is successfully deployed! Click to view button to see the deployed app on Heroku.

該應用已成功部署！ 單擊查看按鈕以查看Heroku上已部署的應用程序。

最初建立表格 (Building tables initially)

You might run into an error where your tables have not been created before you attempt to get or post data. To solve this, we use the following line in our app.py.

在嘗試獲取或發布數據之前，可能尚未創建表的地方可能會遇到錯誤。 為了解決這個問題，我們在app.py中使用以下行。

@app.before_first_request
def setup():
db.create_all()

自動部署 (Automatic deploy)

We can enable automatic deployment to have changes to the Github master be displayed on Heroku as they are pushed. If you use this method, you’ll want to be sure that you always have a working master branch.

我們可以啟用自動部署，以使對Github主服務器的更改在推送時顯示在Heroku上。 如果使用此方法，則需要確保始終有一個正常的master分支。

Enable automatic deploys 啟用自動部署

結論 (Conclusion)

Coding and building useful software requires the management of complexity. We discussed Github as a version control tool, Pipenv as an environment and package manager and some benefits of having cloud companies manage your databases. These tools help reduce the complexity of building software so developers can focus on building rather than managing.

編碼和構建有用的軟件需要管理復雜性。 我們討論了Github作為版本控制工具，Pipenv作為環境和程序包管理器，以及讓云公司管理您的數據庫的一些好處。 這些工具有助于降低構建軟件的復雜性，因此開發人員可以專注于構建而不是管理。

Practicing proper environment and package management is crucial for data scientists and developers who want their code deployed, built upon, or used in production. Using an environment and package manager such as Pipenv makes many processes, including deployment, more comfortable and more efficient!

對于希望在自己的產品中部署，構建或使用其代碼的數據科學家和開發人員而言，正確的環境和程序包管理至關重要。 使用諸如Pipenv之類的環境和程序包管理器，可以使許多過程(包括部署)更加舒適和高效！

Additionally, having a well managed GitHub master branch with a Pipfile allowed Heroku’s severs to rebuild our app with minimal troubleshooting. This lets us deploy an app from a project directory on GitHub to Heroku in minutes.

此外，擁有一個管理良好的GitHub master分支和一個Pipfile，使Heroku的服務器在很少的故障排除的情況下即可重建我們的應用程序。 這使我們可以在幾分鐘內將應用程序從GitHub上的項目目錄部署到Heroku。

We hope this guide has been helpful and welcome comments and questions, thank you!

希望本指南對您有所幫助，并歡迎提出意見和問題，謝謝！

翻譯自: https://towardsdatascience.com/deploy-a-flask-app-on-heroku-and-connect-it-to-a-jawsdb-mysql-database-10e762bc9160

heroku搭建mysql

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