django-celery-beat时区问题

根据下文源码 可得出在django的settings中配置 DJANGO_CELERY_BEAT_TZ_AWARE 参数可控制celery时间格式

查看celery文档

timezone = 'Asia/Shanghai' # 时间取值时区

enable_utc = False # 涉及时区的时候需要该参数

timezone_aware = False # 关闭aware感知

Django还有一些warning打印出来：/Users/jay/workspace/te/env/lib/python2.7/site-packages/django/db/models/fields/__init__.py:903: RuntimeWarning: DateTimeField TestSuite.update_time received a naive datetime (2014-06-15 14:38:37.873873) while time zone support is active. RuntimeWarning)

这个warning的原因是，Django配置为使用timezone的datetime格式，而datetime.now是不包含timezone信息的。

如果不需要在程序中特别处理时区（timezone-aware），在Django项目的settings.py文件中，可以直接设置为“USE_TZ = False”就省心了。然后，在models.py中简单的设置为“ create_time = models.DateTimeField(auto_now_add=True)”和“update_time = models.DateTimeField(auto_now=True)”。

如果还要保持USE_TZ=True，则可设置为“default=datetime.now().replace(tzinfo=utc)” 。

1. 创建项目

运行下面命令就可以创建一个 django 项目，项目名称叫 mysite ：

$ django-admin.py startproject mysite

创建后的项目目录如下：

mysite

├── manage.py

└── mysite

├── __init__.py

├── settings.py

├── urls.py

└── wsgi.py

1 directory, 5 files

说明：

__init__.py ：让 Python 把该目录当成一个开发包 (即一组模块)所需的文件。 这是一个空文件，一般你不需要修改它。

manage.py ：一种命令行工具，允许你以多种方式与该 Django 项目进行交互。 键入python manage.py help，看一下它能做什么。 你应当不需要编辑这个文件；在这个目录下生成它纯是为了方便。

settings.py ：该 Django 项目的设置或配置。

urls.py：Django项目的URL路由设置。目前，它是空的。

wsgi.py：WSGI web 应用服务器的配置文件。更多细节，查看 How to deploy with WSGI

接下来，你可以修改 settings.py 文件，例如：修改 LANGUAGE_CODE、设置时区 TIME_ZONE

SITE_ID = 1

LANGUAGE_CODE = 'zh_CN'

TIME_ZONE = 'Asia/Shanghai'

USE_TZ = True

上面开启了 [Time zone](https://docs.djangoproject.com/en/1.7/topics/i18n/timezones/) 特性，需要安装 pytz：

$ sudo pip install pytz

2. 运行项目

在运行项目之前，我们需要创建数据库和表结构，这里我使用的默认数据库：

$ python manage.py migrate

Operations to perform:

Apply all migrations: admin, contenttypes, auth, sessions

Running migrations:

Applying contenttypes.0001_initial... OK

Applying auth.0001_initial... OK

Applying admin.0001_initial... OK

Applying sessions.0001_initial... OK

然后启动服务：

$ python manage.py runserver

你会看到下面的输出：

Performing system checks...

System check identified no issues (0 silenced).

January 28, 2015 - 02:08:33

Django version 1.7.1, using settings 'mysite.settings'

Starting development server at http://127.0.0.1:8000/

Quit the server with CONTROL-C.

这将会在端口8000启动一个本地服务器, 并且只能从你的这台电脑连接和访问。 既然服务器已经运行起来了，现在用网页浏览器访问 http://127.0.0.1:8000/。你应该可以看到一个令人赏心悦目的淡蓝色 Django 欢迎页面它开始工作了。

你也可以指定启动端口:

$ python manage.py runserver 8080

以及指定 ip：

$ python manage.py runserver 0.0.0.0:8000

3. 创建 app

前面创建了一个项目并且成功运行，现在来创建一个 app，一个 app 相当于项目的一个子模块。

在项目目录下创建一个 app：

$ python manage.py startapp polls

如果 *** 作成功，你会在 mysite 文件夹下看到已经多了一个叫 polls 的文件夹，目录结构如下：

polls

├── __init__.py

├── admin.py

├── migrations

│ └── __init__.py

├── models.py

├── tests.py

└── views.py

1 directory, 6 files

4. 创建模型

每一个 Django Model 都继承自 django.db.models.Model

在 Model 当中每一个属性 attribute 都代表一个 database field

通过 Django Model API 可以执行数据库的增删改查, 而不需要写一些数据库的查询语句

打开 polls 文件夹下的 models.py 文件。创建两个模型：

import datetime

from django.db import models

from django.utils import timezone

class Question(models.Model):

question_text = models.CharField(max_length=200)

pub_date = models.DateTimeField('date published')

def was_published_recently(self):

return self.pub_date >= timezone.now() - datetime.timedelta(days=1)

class Choice(models.Model):

question = models.ForeignKey(Question)

choice_text = models.CharField(max_length=200)

votes = models.IntegerField(default=0)

然后在 mysite/settings.py 中修改 INSTALLED_APPS 添加 polls：

INSTALLED_APPS = (

'django.contrib.admin',

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.messages',

'django.contrib.staticfiles',

'polls',

)

在添加了新的 app 之后，我们需要运行下面命令告诉 Django 你的模型做了改变，需要迁移数据库：

$ python manage.py makemigrations polls

你会看到下面的输出日志：

Migrations for 'polls':

0001_initial.py:

- Create model Choice

- Create model Question

- Add field question to choice

你可以从 polls/migrations/0001_initial.py 查看迁移语句。

运行下面语句，你可以查看迁移的 sql 语句：

$ python manage.py sqlmigrate polls 0001

输出结果：

BEGIN

CREATE TABLE "polls_choice" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "choice_text" varchar(200) NOT NULL, "votes" integer NOT NULL)

CREATE TABLE "polls_question" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "question_text" varchar(200) NOT NULL, "pub_date" datetime NOT NULL)

CREATE TABLE "polls_choice__new" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "choice_text" varchar(200) NOT NULL, "votes" integer NOT NULL, "question_id" integer NOT NULL REFERENCES "polls_question" ("id"))

INSERT INTO "polls_choice__new" ("choice_text", "votes", "id") SELECT "choice_text", "votes", "id" FROM "polls_choice"

DROP TABLE "polls_choice"

ALTER TABLE "polls_choice__new" RENAME TO "polls_choice"

CREATE INDEX polls_choice_7aa0f6ee ON "polls_choice" ("question_id")

COMMIT

你可以运行下面命令，来检查数据库是否有问题：

$ python manage.py check

再次运行下面的命令，来创建新添加的模型：

$ python manage.py migrate

Operations to perform:

Apply all migrations: admin, contenttypes, polls, auth, sessions

Running migrations:

Applying polls.0001_initial... OK

总结一下，当修改一个模型时，需要做以下几个步骤：

修改 models.py 文件

运行 python manage.py makemigrations 创建迁移语句

运行 python manage.py migrate，将模型的改变迁移到数据库中

你可以阅读 django-admin.py documentation，查看更多 manage.py 的用法。

创建了模型之后，我们可以通过 Django 提供的 API 来做测试。运行下面命令可以进入到 python shell 的交互模式：

$ python manage.py shell

下面是一些测试：

>>>from polls.models import Question, Choice # Import the model classes we just wrote.

# No questions are in the system yet.

>>>Question.objects.all()

[]

# Create a new Question.

# Support for time zones is enabled in the default settings file, so

# Django expects a datetime with tzinfo for pub_date. Use timezone.now()

# instead of datetime.datetime.now() and it will do the right thing.

>>>from django.utils import timezone

>>>q = Question(question_text="What's new?", pub_date=timezone.now())

# Save the object into the database. You have to call save() explicitly.

>>>q.save()

# Now it has an ID. Note that this might say "1L" instead of "1", depending

# on which database you're using. That's no biggieit just means your

# database backend prefers to return integers as Python long integer

# objects.

>>>q.id

1

# Access model field values via Python attributes.

>>>q.question_text

"What's new?"

>>>q.pub_date

datetime.datetime(2012, 2, 26, 13, 0, 0, 775217, tzinfo=<UTC>)

# Change values by changing the attributes, then calling save().

>>>q.question_text = "What's up?"

>>>q.save()

# objects.all() displays all the questions in the database.

>>>Question.objects.all()

[<Question: Question object>]

打印所有的 Question 时，输出的结果是 [<Question: Question object>]，我们可以修改模型类，使其输出更为易懂的描述。修改模型类：

from django.db import models

class Question(models.Model):

# ...

def __str__(self): # __unicode__ on Python 2

return self.question_text

class Choice(models.Model):

# ...

def __str__(self): # __unicode__ on Python 2

return self.choice_text

接下来继续测试：

>>>from polls.models import Question, Choice

# Make sure our __str__() addition worked.

>>>Question.objects.all()

[<Question: What's up?>]

# Django provides a rich database lookup API that's entirely driven by

# keyword arguments.

>>>Question.objects.filter(id=1)

[<Question: What's up?>]

>>>Question.objects.filter(question_text__startswith='What')

[<Question: What's up?>]

# Get the question that was published this year.

>>>from django.utils import timezone

>>>current_year = timezone.now().year

>>>Question.objects.get(pub_date__year=current_year)

<Question: What's up?>

# Request an ID that doesn't exist, this will raise an exception.

>>>Question.objects.get(id=2)

Traceback (most recent call last):

...

DoesNotExist: Question matching query does not exist.

# Lookup by a primary key is the most common case, so Django provides a

# shortcut for primary-key exact lookups.

# The following is identical to Question.objects.get(id=1).

>>>Question.objects.get(pk=1)

<Question: What's up?>

# Make sure our custom method worked.

>>>q = Question.objects.get(pk=1)

# Give the Question a couple of Choices. The create call constructs a new

# Choice object, does the INSERT statement, adds the choice to the set

# of available choices and returns the new Choice object. Django creates

# a set to hold the "other side" of a ForeignKey relation

# (e.g. a question's choice) which can be accessed via the API.

>>>q = Question.objects.get(pk=1)

# Display any choices from the related object set -- none so far.

>>>q.choice_set.all()

[]

# Create three choices.

>>>q.choice_set.create(choice_text='Not much', votes=0)

<Choice: Not much>

>>>q.choice_set.create(choice_text='The sky', votes=0)

<Choice: The sky>

>>>c = q.choice_set.create(choice_text='Just hacking again', votes=0)

# Choice objects have API access to their related Question objects.

>>>c.question

<Question: What's up?>

# And vice versa: Question objects get access to Choice objects.

>>>q.choice_set.all()

[<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]

>>>q.choice_set.count()

3

# The API automatically follows relationships as far as you need.

# Use double underscores to separate relationships.

# This works as many levels deep as you wantthere's no limit.

# Find all Choices for any question whose pub_date is in this year

# (reusing the 'current_year' variable we created above).

>>>Choice.objects.filter(question__pub_date__year=current_year)

[<Choice: Not much>, <Choice: The sky>, <Choice: Just hacking again>]

# Let's delete one of the choices. Use delete() for that.

>>>c = q.choice_set.filter(choice_text__startswith='Just hacking')

>>>c.delete()

>>>

上面这部分测试，涉及到 django orm 相关的知识，详细说明可以参考 Django中的ORM。

5. 管理 admin

Django有一个优秀的特性, 内置了Django admin后台管理界面, 方便管理者进行添加和删除网站的内容.

新建的项目系统已经为我们设置好了后台管理功能，见 mysite/settings.py：

INSTALLED_APPS = (

'django.contrib.admin', #默认添加后台管理功能

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.messages',

'django.contrib.staticfiles',

'mysite',

)

同时也已经添加了进入后台管理的 url, 可以在 mysite/urls.py 中查看：

url(r'^admin/', include(admin.site.urls)), #可以使用设置好的url进入网站后台

接下来我们需要创建一个管理用户来登录 admin 后台管理界面：

$ python manage.py createsuperuser

Username (leave blank to use 'june'): admin

Email address:

Password:

Password (again):

Superuser created successfully.

总结

最后，来看项目目录结构：

mysite

├── db.sqlite3

├── manage.py

├── mysite

│ ├── __init__.py

│ ├── settings.py

│ ├── urls.py

│ ├── wsgi.py

├── polls

│ ├── __init__.py

│ ├── admin.py

│ ├── migrations

│ │ ├── 0001_initial.py

│ │ ├── __init__.py

│ ├── models.py

│ ├── templates

│ │ └── polls

│ │ ├── detail.html

│ │ ├── index.html

│ │ └── results.html

│ ├── tests.py

│ ├── urls.py

│ ├── views.py

└── templates

└── admin

└── base_site.htm

通过上面的介绍，对 django 的安装、运行以及如何创建视 图和模型有了一个清晰的认识，接下来就可以深入的学习 django 的自动化测试、持久化、中间件、国 际 化等知识。

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