【已解决】gunicorn运行Flask的app但访问出错：org.apache.http.conn.HttpHostConnectException Connect to failed Operation timed out

折腾：

【已解决】把Python3的Flask部署到远程CentOS7服务器

期间，Flask的app，用gunicorn去运行，是可以运行的，但是客户端去访问api出错：

[root@naturling-general-01 robotDemo]# pipenv shell

Warning: Your Pipfile requires python_version 3.6, but you are using 3.4.5 (/root/.local/share/v/r/bin/python).

  $ pipenv check will surely fail.

Spawning environment shell (/bin/bash). Use ‘exit’ to leave.

[root@naturling-general-01 robotDemo]# . /root/.local/share/virtualenvs/robotDemo-dwdcgdaG/bin/activate

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# ll

total 40

-rw-r–r– 1 root root  8516 Apr 23 10:27 app.py

-rw-r–r– 1 root root  1700 Apr 23 17:28 gunicorn_config.py

-rw-r–r– 1 root root   212 Apr 20 10:15 Pipfile

-rw-r–r– 1 root root  7936 Apr 23 11:37 Pipfile.lock

-rw-r–r– 1 root root 10317 Apr 23 10:30 supervisord.conf

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# mkdir logs

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# ll

total 44

-rw-r–r– 1 root root  8516 Apr 23 10:27 app.py

-rw-r–r– 1 root root  1700 Apr 23 17:28 gunicorn_config.py

drwxr-xr-x 2 root root  4096 Apr 23 17:45 logs

-rw-r–r– 1 root root   212 Apr 20 10:15 Pipfile

-rw-r–r– 1 root root  7936 Apr 23 11:37 Pipfile.lock

-rw-r–r– 1 root root 10317 Apr 23 10:30 supervisord.conf

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# cd logs

(robotDemo-dwdcgdaG) [root@naturling-general-01 logs]# cd ..

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# ll

total 44

-rw-r–r– 1 root root  8516 Apr 23 10:27 app.py

-rw-r–r– 1 root root  1700 Apr 23 17:28 gunicorn_config.py

drwxr-xr-x 2 root root  4096 Apr 23 17:45 logs

-rw-r–r– 1 root root   212 Apr 20 10:15 Pipfile

-rw-r–r– 1 root root  7936 Apr 23 11:37 Pipfile.lock

-rw-r–r– 1 root root 10317 Apr 23 10:30 supervisord.conf

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# gunicorn

gunicorn         gunicorn_paster  

(robotDemo-dwdcgdaG) [root@naturling-general-01 robotDemo]# gunicorn -c gunicorn_config.py app:app

currentRootPath=/root/naturling_20180101/web/server/robotDemo

[2018-04-23 17:46:18,376 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e90cf8>

[2018-04-23 17:46:18,380 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,434 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e90d68>

[2018-04-23 17:46:18,437 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,461 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e91da0>

[2018-04-23 17:46:18,464 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,475 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e91e10>

[2018-04-23 17:46:18,477 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,586 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e91e80>

[2018-04-23 17:46:18,588 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,644 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e91ef0>

[2018-04-23 17:46:18,646 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,691 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5203117f98>

[2018-04-23 17:46:18,694 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,742 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e8ffd0>

[2018-04-23 17:46:18,744 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

[2018-04-23 17:46:18,785 INFO app.py:59 <module>] api=<flask_restful.Api object at 0x7f5202e98080>

[2018-04-23 17:46:18,787 INFO app.py:80 <module>] purePymongo=MongoClient(host=[‘x.x.x.x:port’], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’)

但是访问端口失败：

org.apache.http.conn.HttpHostConnectException: Connect to x.x.x.x:port [/x.x.x.x] failed: Operation timed out (Connection timed out)

想起来了，是阿里云的端口问题，所以去加上安全组的规则：

port

然后再去试试API访问

结果错误依旧：

org.apache.http.conn.HttpHostConnectException: Connect to x.x.x:port [/x.x.x.x] failed: Connection refused (Connection refused)

难道是：

此处app的run中，没有加上：

host="0.0.0.0"

去加上试试

问题依旧，去看log：

cat logs/gunicorn_error.log

[2018-04-23 17:58:09 +0800] [22119] [INFO] Listening at: http://127.0.0.1:32851 (22119)

[2018-04-23 17:58:09 +0800] [22119] [INFO] Using worker: threads

[2018-04-23 17:58:09 +0800] [22122] [INFO] Booting worker with pid: 22122

好像是：

实际上此处内部还只是：http://127.0.0.1

不允许外部访问？

gunicorn flask Connect to failed Connection refused

flask + nginx = connection refused – Stack Overflow

python – Flask – Gunicorn returns 404 after curl to localhost on same instance – Stack Overflow

502 Bad Gateway Ngnix &amp; Gunicorn | DigitalOcean

Getting nginx proxy to work properly with gunicorn/flask – Server Fault

换postman试试

直接没有响应

Could not get any response

There was an error connecting to http://x.x.x.x:yyy/qa?q=play%20a%20happy%20song.

Why this might have happened:

* The server couldn’t send a response:

Ensure that the backend is working properly

* Self-signed SSL certificates are being blocked:

Fix this by turning off ‘SSL certificate verification’ in Settings > General

* Proxy configured incorrectly

Ensure that proxy is configured correctly in Settings > Proxy

* Request timeout:

Change request timeout in Settings > General

flask deploy  Connect to failed Connection refused

deployment – Nginx and uWSGI Flask app Connection Refused – Server Fault

看到都提到了nginx

-》难道部署是，必须使用nginx？

Connection refused with uwsgi and nginx | DigitalOcean

python – Can’t deploy Flask with Nginx – Stack Overflow

python – Flask + Tornado application – how to communicate with server (Connection refused) – Stack Overflow

“ either permission problem or nothing running on that port”

看来就是：

端口问题或者是权限问题

使用nginx+uwsgi来部署django服务 – 简书

Fix for Connection Reset on POST | Flask (A Python Microframework)

flask deploy Could not get any response

I’m having issues using nginx to route my Flask app. What am I doing wrong? | DigitalOcean

python – Configure Flask dev server to be visible across the network – Stack Overflow

python 2.7 – Flask web app not responding to external requests on EC2 – Stack Overflow

ubuntu – Unable to Connect to Flask App On Docker From Host – Stack Overflow

结果log中还是127的：

[2018-04-24 09:07:43 +0800] [23413] [INFO] Listening at: http://127.0.0.1:32851 (23413)

[2018-04-24 09:07:43 +0800] [23413] [INFO] Using worker: threads

[2018-04-24 09:07:43 +0800] [23416] [INFO] Booting worker with pid: 23416

算了，手动运行自己的flask的app试试：

python app.py

可以运行的，但是出错：

【已解决】pymongo的count()出错：pymongo.errors.ServerSelectionTimeoutError timed out

所以现在问题变成：

手动执行是可以的：

python app.py

但是换成gunicorn运行，结果却访问被拒绝了。

gunicorn deploy flask connection refused

python – Why can’t I connect to Flask server when hosted remotely? – Stack Overflow

python – Why shouldn’t Flask be deployed with the built in server? – Stack Overflow

python – Configure Flask dev server to be visible across the network – Stack Overflow

python – Consistent connection refused error while using gunicorn within a docker container – Stack Overflow

然后才想到：

去看gunicorn的配置

发现了，gunicorn中配置的是：

bind = ‘127.0.0.1:32851’                        #绑定ip和端口号

应该就是这个127.0.0.1，导致了不允许外部访问。

所以去改为：

#bind = ‘127.0.0.1:32851’                        #绑定ip和端口号

bind = ‘0.0.0.0:32851’                        #绑定ip和端口号

然后再去试试

gunicorn -c gunicorn_config.py app:app

结果就可以了。

【总结】

此处对于在服务器中：

Flask的app，单独手动：

python app.py

是可以正常运行，然后远程Mac本地是可以访问服务器上的接口的。

而换成gunicorn后去运行，远程访问接口就出错：

org.apache.http.conn.HttpHostConnectException Connect to failed Operation timed out

org.apache.http.conn.HttpHostConnectException: Connect to failed: Connection refused (Connection refused)

Could not get any response

原因是：

此处阿里云服务器的端口号也没有开放

Flask的app中的host也不是0.0.0.0

gunicorn中host是127.0.0.1

解决办法：

依次解决掉：

（1）去阿里云ECS的安全组中，加上允许入方向访问端口

（2）把Flask中app的host改为0.0.0.0

app.py

if __name__ == "__main__":

    app.run(

        host="0.0.0.0",

        port=SERVER_PORT,

        debug=DEBUG

    )

（3）把gunicorn中的host改为0.0.0.0

gunicorn_config.py

#bind = ‘127.0.0.1:32851’                        #绑定ip和端口号

bind = ‘0.0.0.0:32851’                        #绑定ip和端口号

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