摘要：本文以使用阿里云函數(shù)計(jì)算為例，構(gòu)建一個(gè)簡單具體的為例，看看這種架構(gòu)是如何達(dá)到快速開發(fā)和節(jié)約運(yùn)維成本的。方案在本文中，我們運(yùn)用阿里云函數(shù)計(jì)算表格存儲(chǔ)，就能快速搭建這個(gè)服務(wù)，會(huì)自動(dòng)去應(yīng)對(duì)請(qǐng)求流量，同樣函數(shù)計(jì)算也會(huì)根據(jù)流量自動(dòng)。

摘要： Serverless 是一種架構(gòu)理念，具有自己的獨(dú)特的優(yōu)勢和適用場景。本文以使用阿里云函數(shù)計(jì)算為例，構(gòu)建一個(gè)簡單具體的microservice為例，看看這種架構(gòu)是如何達(dá)到快速開發(fā)和節(jié)約運(yùn)維成本的。

點(diǎn)此查看原文：http://click.aliyun.com/m/41322/

Serverless 是一種架構(gòu)理念，具有自己的獨(dú)特的優(yōu)勢和適用場景。本文以使用阿里云函數(shù)計(jì)算為例，構(gòu)建一個(gè)簡單具體的microservice為例，看看這種架構(gòu)是如何達(dá)到快速開發(fā)和節(jié)約運(yùn)維成本的。

應(yīng)用場景1

某游戲公司剛開發(fā)完一個(gè)新的游戲，想要進(jìn)行一些封閉測試，他們需要一個(gè)管理激活碼的service來邀請(qǐng)有激活碼的玩家來參與封閉測試，同時(shí)可能對(duì)積極參與封閉測試的玩家，等正式開服后，給予一定的禮包券碼

應(yīng)用場景2

某垂直領(lǐng)域的電商，剛剛起步，流量不是特別大，但發(fā)展勢頭不錯(cuò)。他們需要一個(gè)管理優(yōu)惠碼的service

針對(duì)上面所說的兩個(gè)場景，無論是優(yōu)惠碼，激活碼等相關(guān)碼的管理，一般有如下四個(gè)：

生成碼
使用碼
驗(yàn)證碼
刪除碼

傳統(tǒng)方案

用戶自己去架設(shè)服務(wù)器，配置數(shù)據(jù)庫，再編寫對(duì)應(yīng)的服務(wù)，再配備相應(yīng)的運(yùn)維人員，總之，不管是硬件成本還是人力成本都不少。

serverless 方案
在本文中，我們運(yùn)用阿里云API Gateway + 函數(shù)計(jì)算 + 表格存儲(chǔ)(OTS)，就能快速搭建這個(gè)服務(wù)，API Gateway 會(huì)自動(dòng) scale 去應(yīng)對(duì)請(qǐng)求流量，同樣函數(shù)計(jì)算也會(huì)根據(jù)流量自動(dòng) scale。開發(fā)方面，只需要實(shí)現(xiàn)好對(duì)應(yīng)的邏輯函數(shù)即可。運(yùn)維方面，省去了管理密匙、打安全補(bǔ)丁等工作，因?yàn)橛脩舾緵]有需要維護(hù)的機(jī)器。整個(gè)解決方案如下圖：

從上圖我們可以看出，主要有兩個(gè)步驟：

函數(shù)計(jì)算作為 API 網(wǎng)關(guān)后端服務(wù), 具體的教程可以參考官方教程和函數(shù)計(jì)算獲取臨時(shí)token
函數(shù)計(jì)算結(jié)合ots實(shí)現(xiàn)具體的邏輯，本文主要講解這個(gè)過程, 并給出具體的代碼。

具體步驟

1, 創(chuàng)建一個(gè)ots實(shí)例，并在實(shí)例中創(chuàng)建一張表；在本例中，是在華東2 region創(chuàng)建了code-ots實(shí)例，并在該實(shí)例中創(chuàng)建了一張表code, 主鍵是STRING類型

2, 創(chuàng)建對(duì)應(yīng)的service，service下面創(chuàng)建4個(gè)函數(shù)，分別為gen_code, del_code, query_code, use_code, 具體的代碼可以在本文最后附件下載，由于函數(shù)要訪問ots，這邊需要配置service可以讀寫ots的權(quán)限，相關(guān)授權(quán)教程可以參考函數(shù)計(jì)算實(shí)現(xiàn)流式處理大文件中的具體步驟第2步, 本文最后配置如下圖，從下圖可知，我們創(chuàng)建的service的服務(wù)角色是fc-ots-rw,該角色擁有對(duì)ots讀寫的權(quán)限。

具體function

1 生成碼
配置event

{
    "num":1000,
    "start period":"2017-12-22 00:00:00",
    "end period":"2017-12-28 00:00:00",
}

通過這個(gè)配置的event，設(shè)置的目標(biāo)是產(chǎn)生1000個(gè)碼， 碼的有效期在2017-12-22 00:00:00 至 2017-12-28 00:00:00，默認(rèn)產(chǎn)生的狀態(tài)都是UNACTIVED，未激活的

code

# -*- coding: utf-8 -*-
import uuid
import json
import time
from tablestore import *
from tablestore.retry import WriteRetryPolicy
  
table_name = "code"  # 具體的table
ots_name = "code-ots"  # ots 實(shí)例
BATCH_NUM =  200

def batch_write_row(client, start, end, num):
    put_row_items = []
    for i in range(0, num):
        uid_str = str(uuid.uuid1())
        primary_key = [("uuid", uid_str)]
        attribute_columns = [("start", start), ("end", end), ("status", "UNACTIVED")]
        row = Row(primary_key, attribute_columns)
        condition = Condition(RowExistenceExpectation.EXPECT_NOT_EXIST)
        item = PutRowItem(row, condition)
        put_row_items.append(item)

    request = BatchWriteRowRequest()
    request.add(TableInBatchWriteRowItem(table_name, put_row_items))
    result = client.batch_write_row(request)

    succ, fail = result.get_put()
    print ("check input table"s put results: is_all_succeed={0}; succ_num={1}; 
            fail_um={2}".format(result.is_all_succeed(), len(succ), len(fail)))
    
    for item in fail:
        print ("Put failed, error code: %s, error message: %s" % (item.error_code, item.error_message))
             
def upload_ots(context, num, start, end):
    endpoint = "https://{}.cn-shanghai.ots-internal.aliyuncs.com".format(ots_name)
    creds = context.credentials
    client = OTSClient(endpoint, creds.accessKeyId,  creds.accessKeySecret, ots_name, 
            sts_token = creds.securityToken, retry_policy = WriteRetryPolicy())
    
    while num > 0:
        w_num = num
        if num > BATCH_NUM:
            w_num = BATCH_NUM
        batch_write_row(client, start, end, w_num)
        num = num - w_num
            
def handler(event, context):
    evt = json.loads(event)
    num = int(evt["num"])
    start = evt["start period"]
    end = evt["end period"]
    start_t = time.mktime(time.strptime(start, "%Y-%m-%d %H:%M:%S"))
    end_t = time.mktime(time.strptime(end, "%Y-%m-%d %H:%M:%S"))
    print uuid.uuid1(), type(uuid.uuid1())
    upload_ots(context, num, start_t, end_t)
    return "ok"

2 使用碼

配置event

{
   "uuid":"254804e8-e707-11e7-9c21-0242ac110004"
}

假設(shè)使用碼254804e8-e707-11e7-9c21-0242ac110004，只有表中存在這個(gè)碼并且這個(gè)碼是UNACTIVED才返回SUCCESS，并且把該碼的狀態(tài)設(shè)置為ACTIVED。其他情況，比如不存在這個(gè)碼，或者是存在這個(gè)碼但是已經(jīng)被激活使用過，都返回FAIL

code

# -*- coding: utf-8 -*-
from tablestore import *
from tablestore.retry import WriteRetryPolicy
import json

table_name = "code"
ots_name = "code-ots"

def update_row(client, uuid):
    primary_key = [("uuid",uuid)]
    update_of_attribute_columns = {
        "PUT" : [("status","ACTIVED")],
    }
    row = Row(primary_key, update_of_attribute_columns)
    condition = Condition(RowExistenceExpectation.EXPECT_EXIST, SingleColumnCondition("status", "UNACTIVED", ComparatorType.EQUAL)) 
    try:
        consumed, return_row = client.update_row(table_name, row, condition) 
        print ("Update succeed, consume %s write cu." % consumed.write)
    except Exception as e:
        return "FAILED"
    return "SUCCEED"
      
def handler(event, context):
    endpoint = "https://{}.cn-shanghai.ots-internal.aliyuncs.com".format(ots_name)
    creds = context.credentials
    client = OTSClient(endpoint, creds.accessKeyId,  creds.accessKeySecret, ots_name, 
            sts_token = creds.securityToken, retry_policy = WriteRetryPolicy())
    evt = json.loads(event)
    uuid = str(evt["uuid"])
    return update_row(client, uuid)

3 查詢碼

配置event

{
   "uuid":"254804e8-e707-11e7-9c21-0242ac110004"
}

假設(shè)查詢碼254804e8-e707-11e7-9c21-0242ac110004，只有表中不存在這個(gè)碼返回NO EXISTED, 存在的話，則返回表中記錄的狀態(tài)

code

# -*- coding: utf-8 -*-
from tablestore import *
from tablestore.retry import WriteRetryPolicy
import time,json

table_name = "code"
ots_name = "code-ots"

def get_row(client, uuid):
    primary_key = [("uuid", uuid)]
    columns_to_get = []

    cond = CompositeColumnCondition(LogicalOperator.OR)
    cond.add_sub_condition(SingleColumnCondition("status", "UNACTIVED", ComparatorType.NOT_EQUAL))
    cond.add_sub_condition(SingleColumnCondition("status", "UNACTIVED", ComparatorType.EQUAL))

    consumed, return_row, next_token = client.get_row(table_name, primary_key, columns_to_get, cond, 1)
    print ("Read succeed, consume %s read cu." % consumed.read)

    if return_row is None:
        return "NO EXISTED"

    
    status = "UNKNOWN"
    for att in return_row.attribute_columns:
        print ("name:%s	value:%s	timestamp:%d" % (att[0], att[1], att[2]))
        if att[0] == "status":
            status = att[1]
        if att[0] == "start":
            start = att[1]
        if att[0] == "end":
            end = att[1]

    current_time = time.time()
    if current_time > end or current_time < start:
        status = "TIMEINVALID"
    return status   

def handler(event, context):
    endpoint = "https://{}.cn-shanghai.ots-internal.aliyuncs.com".format(ots_name)
    creds = context.credentials
    client = OTSClient(endpoint, creds.accessKeyId,  creds.accessKeySecret, ots_name, 
            sts_token = creds.securityToken, retry_policy = WriteRetryPolicy())
    evt = json.loads(event)
    uuid = str(evt["uuid"])
    return get_row(client, uuid)

4 刪除碼

配置event

{
   "uuid":"254804e8-e707-11e7-9c21-0242ac110004"
}

假設(shè)刪除碼254804e8-e707-11e7-9c21-0242ac110004，不管表中是否存在這個(gè)碼，只要表中沒有這個(gè)碼了就是成功刪除，除非ots sdk delete_row拋出異常

code

# -*- coding: utf-8 -*-
from tablestore import *
from tablestore.retry import WriteRetryPolicy
import json

table_name = "code"
ots_name = "code-ots"

def delete_row(client, uuid):
    primary_key = [("uuid",uuid)]
    row = Row(primary_key)
    condition = Condition(RowExistenceExpectation.IGNORE, SingleColumnCondition("status", "", ComparatorType.NOT_EQUAL))
    try:
        consumed, return_row = client.delete_row(table_name, row, condition) 
        print ("Delete succeed, consume %s write cu." % consumed.write)
    except:
        return "FAILED"
    
    return "SUCCEED"
      
def handler(event, context):
    endpoint = "https://{}.cn-shanghai.ots-internal.aliyuncs.com".format(ots_name)
    creds = context.credentials
    client = OTSClient(endpoint, creds.accessKeyId,  creds.accessKeySecret, ots_name, 
            sts_token = creds.securityToken, retry_policy = WriteRetryPolicy())
    evt = json.loads(event)
    uuid = str(evt["uuid"])
    return delete_row(client, uuid)