将django迁移到腾讯云函数计算

前提：已经在电脑上安装了serverless框架

1. 修改项目的入口函数

由于采用了serverless，我们不再需要关心底层的服务器软件，因此我们需要改写腾讯云serverless的入口函数，使之传入的参数形式与django所需的参数相匹配。

在项目根目录下新建index.py：

只需要把倒数两行对应的适配你的项目名字就好了。

# -*- coding: utf-8 -*-

import os
import sys
import base64
from werkzeug.datastructures import Headers, MultiDict
from werkzeug.wrappers import Response
from werkzeug.urls import url_encode, url_unquote
from werkzeug.http import HTTP_STATUS_CODES
from werkzeug._compat import BytesIO, string_types, to_bytes, wsgi_encoding_dance
import RepairReportBackend.wsgi

TEXT_MIME_TYPES = [
    "application/json",
    "application/javascript",
    "application/xml",
    "application/vnd.api+json",
    "image/svg+xml",
]


def all_casings(input_string):
    if not input_string:
        yield ""
    else:
        first = input_string[:1]
        if first.lower() == first.upper():
            for sub_casing in all_casings(input_string[1:]):
                yield first + sub_casing
        else:
            for sub_casing in all_casings(input_string[1:]):
                yield first.lower() + sub_casing
                yield first.upper() + sub_casing


def split_headers(headers):
    """
    If there are multiple occurrences of headers, create case-mutated variations
    in order to pass them through APIGW. This is a hack that's currently
    needed. See: https://github.com/logandk/serverless-wsgi/issues/11
    Source: https://github.com/Miserlou/Zappa/blob/master/zappa/middleware.py
    """
    new_headers = {}

    for key in headers.keys():
        values = headers.get_all(key)
        if len(values) > 1:
            for value, casing in zip(values, all_casings(key)):
                new_headers[casing] = value
        elif len(values) == 1:
            new_headers[key] = values[0]

    return new_headers


def group_headers(headers):
    new_headers = {}

    for key in headers.keys():
        new_headers[key] = headers.get_all(key)

    return new_headers


def encode_query_string(event):
    multi = event.get(u"multiValueQueryStringParameters")
    if multi:
        return url_encode(MultiDict((i, j) for i in multi for j in multi[i]))
    else:
        return url_encode(event.get(u"queryString") or {})


def handle_request(application, event, context):

    if u"multiValueHeaders" in event:
        headers = Headers(event["multiValueHeaders"])
    else:
        headers = Headers(event["headers"])

    strip_stage_path = os.environ.get("STRIP_STAGE_PATH", "").lower().strip() in [
        "yes",
        "y",
        "true",
        "t",
        "1",
    ]
    if u"apigw.tencentcs.com" in headers.get(u"Host", u"") and not strip_stage_path:
        script_name = "/{}".format(event["requestContext"].get(u"stage", ""))
    else:
        script_name = ""

    path_info = event["path"]
    base_path = os.environ.get("API_GATEWAY_BASE_PATH")
    if base_path:
        script_name = "/" + base_path

        if path_info.startswith(script_name):
            path_info = path_info[len(script_name) :] or "/"

    if u"body" in event:
        body = event[u"body"] or ""
    else:
        body = ""

    if event.get("isBase64Encoded", False):
        body = base64.b64decode(body)
    if isinstance(body, string_types):
        body = to_bytes(body, charset="utf-8")

    environ = {
        "CONTENT_LENGTH": str(len(body)),
        "CONTENT_TYPE": headers.get(u"Content-Type", ""),
        "PATH_INFO": url_unquote(path_info),
        "QUERY_STRING": encode_query_string(event),
        "REMOTE_ADDR": event["requestContext"]
        .get(u"identity", {})
        .get(u"sourceIp", ""),
        "REMOTE_USER": event["requestContext"]
        .get(u"authorizer", {})
        .get(u"principalId", ""),
        "REQUEST_METHOD": event["httpMethod"],
        "SCRIPT_NAME": script_name,
        "SERVER_NAME": headers.get(u"Host", "lambda"),
        "SERVER_PORT": headers.get(u"X-Forwarded-Port", "80"),
        "SERVER_PROTOCOL": "HTTP/1.1",
        "wsgi.errors": sys.stderr,
        "wsgi.input": BytesIO(body),
        "wsgi.multiprocess": False,
        "wsgi.multithread": False,
        "wsgi.run_once": False,
        "wsgi.url_scheme": headers.get(u"X-Forwarded-Proto", "http"),
        "wsgi.version": (1, 0),
        "serverless.authorizer": event["requestContext"].get(u"authorizer"),
        "serverless.event": event,
        "serverless.context": context,
        # TODO: Deprecate the following entries, as they do not comply with the WSGI
        # spec. For custom variables, the spec says:
        #
        #   Finally, the environ dictionary may also contain server-defined variables.
        #   These variables should be named using only lower-case letters, numbers, dots,
        #   and underscores, and should be prefixed with a name that is unique to the
        #   defining server or gateway.
        "API_GATEWAY_AUTHORIZER": event["requestContext"].get(u"authorizer"),
        "event": event,
        "context": context,
    }

    for key, value in environ.items():
        if isinstance(value, string_types):
            environ[key] = wsgi_encoding_dance(value)

    for key, value in headers.items():
        key = "HTTP_" + key.upper().replace("-", "_")
        if key not in ("HTTP_CONTENT_TYPE", "HTTP_CONTENT_LENGTH"):
            environ[key] = value

    response = Response.from_app(application, environ)

    returndict = {u"statusCode": response.status_code}

    if u"multiValueHeaders" in event:
        returndict["multiValueHeaders"] = group_headers(response.headers)
    else:
        returndict["headers"] = split_headers(response.headers)

    if event.get("requestContext").get("elb"):
        # If the request comes from ALB we need to add a status description
        returndict["statusDescription"] = u"%d %s" % (
            response.status_code,
            HTTP_STATUS_CODES[response.status_code],
        )

    if response.data:
        mimetype = response.mimetype or "text/plain"
        if (
            mimetype.startswith("text/") or mimetype in TEXT_MIME_TYPES
        ) and not response.headers.get("Content-Encoding", ""):
            returndict["body"] = response.get_data(as_text=True)
            returndict["isBase64Encoded"] = False
        else:
            returndict["body"] = base64.b64encode(response.data).decode("utf-8")
            returndict["isBase64Encoded"] = True

    return returndict


from django.conf import settings

def main_handler(event, context):
# 因为我把所有的静态文件都存在了腾讯云cos，因此，在settings.py中，先把下面的STATIC_FC_URL设置为和static_url相同即可。
    settings.STATIC_URL = event['host'] + '/' + settings.STATIC_FC_URL
    return handle_request(myDjangoProject.wsgi.application, event, context)

2. 配置腾讯云COS

由于我把所有的静态文件都存在了腾讯云cos，因此需要先使用

python manage.py collectstatic

将所有的静态文件都收集了，然后把整个static文件夹传到腾讯云cos上面。

但是这个时候，有些js和css是无法正常调用的，那是因为腾讯云cos的安全策略的问题。需要在跨域访问CORS设置中，把你的来路域名添加进去，这样网页就能正常显示了。

3. 安装项目依赖

在项目根目录下创建requirements.txt，将 Python 所需要的依赖安装到项目目录

pip install -r requirements.txt -t ./

4. 配置 yml 文件

在项目根目录下，新建 serverless.yml 文件，并将下列配置模版粘贴到文件中，实现基本的项目配置。

#serverless.yml
component: django
name: djangoDemo

app: appDemo
stage: dev

inputs:
  region: ap-guangzhou
  djangoProjectName: mydjangocomponent
  src: ./src
  functionConf:
    timeout: 10
    memorySize: 256
    environment:
      variables:
        TEST: vale
  apigatewayConf:
    protocols:
      - https
    environment: release