Running on server isn't getting /socket.io/ request

[devx5f]

Hello, I'm having problems getting sockets initiated when running the code on our sever. It's working locally where I'm able to see GET /socket.io/ running on a mac device using docker, but when moving to a linux server it's just showing [DEBUG] Closing connection. without any initial get socket request or initialization.

Any guidance on what may be up would be really appreciated, thank you!

# app.py
def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)
    db.init_app(app)
    migrate = Migrate(app, db)
    socketio.init_app(app)

    app.register_blueprint(blueprint)
    logger.info(f"App has started!")
    return app

socket_events.py
socketio = SocketIO(max_http_buffer_size=10000000, cors_allowed_origins=[], logger=True, engineio_logger=True)

@socketio.on('connect')
def test_connect(auth):
    logger.info(f'Socket connected: ')

# entrypoint.sh
gunicorn --workers=1  --threads 100 --timeout=7200 --bind=0.0.0.0:8080 --log-level=debug --access-logformat='%(h)s - - [%(t)s] "%(r)s" %(s)s %(b)s %(L)s' --access-logfile=- "app.api.src.app:create_app()" 

# Dockerfile
FROM python:3.10.16

RUN apt-get update && apt-get install -y \
    ffmpeg \
    libhdf5-dev \
    nano \
    && rm -rf /var/lib/apt/lists/*

ENV USERNAME=test-app
ENV WORKING_DIR=/home/test-app
WORKDIR ${WORKING_DIR}

COPY requirements.txt .

COPY app app
COPY entrypoint.sh .
COPY migrations migrations

RUN groupadd ${USERNAME} && \
    useradd -g ${USERNAME} ${USERNAME}

RUN chown -R ${USERNAME}:${USERNAME} ${WORKING_DIR}
RUN chmod -R u=rwx,g=rwx ${WORKING_DIR}

USER ${USERNAME}
ENV PATH "$PATH:/home/${USERNAME}/.local/bin"

ENV PYTHONUNBUFFERED=1

ENV FLASK_APP=/home/test-app/app/api/src/app.py
RUN chmod +x entrypoint.sh

EXPOSE 8080

ENTRYPOINT [ "sh", "entrypoint.sh" ]

[miguelgrinberg]

Can you provide complete server logs please?

[devx5f]

Thank you for responding! Here's the log, I noticed that the socket.io is being initialized twice from another discussion that could be factoring in but I'm seeing that both locally and on the server so seems like there's something else going on

Running migrations...
<flask_socketio.SocketIO object at 0x7efca17ba260>                                                      
Server initialized for threading.
26-01-11 13:10:37 - App has started!
INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO  [alembic.runtime.migration] Will assume transactional DDL.
Completed migrations.
Starting the application...
[2026-01-11 13:10:39 +0000] [28] [DEBUG] Current configuration:
config: ./gunicorn.conf.py
wsgi_app: None
bind: ['0.0.0.0:8080']
backlog: 2048
workers: 1
worker_class: sync
threads: 200
worker_connections: 1000
max_requests: 0
max_requests_jitter: 0
timeout: 7200
graceful_timeout: 30
keepalive: 2
limit_request_line: 4094
limit_request_fields: 100
limit_request_field_size: 8190
reload: False
reload_engine: auto
reload_extra_files: []
spew: False
check_config: False
print_config: False
preload_app: False
sendfile: None
reuse_port: False
chdir: /home/test-app
daemon: False
raw_env: []
pidfile: None
worker_tmp_dir: None
user: 1000
group: 1000
umask: 0
initgroups: False
tmp_upload_dir: None
secure_scheme_headers: {'X-FORWARDED-PROTOCOL': 'ssl', 'X-FORWARDED-PROTO': 'https', 'X-FORWARDED-SSL': 'on'}
forwarded_allow_ips: ['127.0.0.1', '::1']
accesslog: -
disable_redirect_access_to_syslog: False
access_log_format: %(h)s - - [%(t)s] "%(r)s" %(s)s %(b)s %(L)s
errorlog: -
loglevel: debug
capture_output: False
logger_class: gunicorn.glogging.Logger
logconfig: None
logconfig_dict: {}
logconfig_json: None
syslog_addr: udp://localhost:514
syslog: False
syslog_prefix: None
syslog_facility: user
enable_stdio_inheritance: False
statsd_host: None
dogstatsd_tags:
statsd_prefix:
proc_name: None
default_proc_name: app.api.src.app:create_app()
pythonpath: None
paste: None
on_starting: <function OnStarting.on_starting at 0x7f0d3e75e710>
on_reload: <function OnReload.on_reload at 0x7f0d3e75e830>
when_ready: <function WhenReady.when_ready at 0x7f0d3e75e950>
pre_fork: <function Prefork.pre_fork at 0x7f0d3e75ea70>
post_fork: <function Postfork.post_fork at 0x7f0d3e75eb90>
post_worker_init: <function PostWorkerInit.post_worker_init at 0x7f0d3e75ecb0>
worker_int: <function WorkerInt.worker_int at 0x7f0d3e75edd0>
worker_abort: <function WorkerAbort.worker_abort at 0x7f0d3e75eef0>
pre_exec: <function PreExec.pre_exec at 0x7f0d3e75f010>
pre_request: <function PreRequest.pre_request at 0x7f0d3e75f130>
post_request: <function PostRequest.post_request at 0x7f0d3e75f1c0>
child_exit: <function ChildExit.child_exit at 0x7f0d3e75f2e0>
worker_exit: <function WorkerExit.worker_exit at 0x7f0d3e75f400>
nworkers_changed: <function NumWorkersChanged.nworkers_changed at 0x7f0d3e75f520>
on_exit: <function OnExit.on_exit at 0x7f0d3e75f640>
ssl_context: <function NewSSLContext.ssl_context at 0x7f0d3e75f760>
proxy_protocol: False
proxy_allow_ips: ['127.0.0.1', '::1']
keyfile: None
certfile: None
ssl_version: 2
cert_reqs: 0
ca_certs: None
suppress_ragged_eofs: True
do_handshake_on_connect: False
ciphers: None
raw_paste_global_conf: []
permit_obsolete_folding: False
strip_header_spaces: False
permit_unconventional_http_method: False
permit_unconventional_http_version: False
casefold_http_method: False
forwarder_headers: ['SCRIPT_NAME', 'PATH_INFO']
header_map: drop
[2026-01-11 13:10:39 +0000] [28] [INFO] Starting gunicorn 23.0.0
[2026-01-11 13:10:39 +0000] [28] [DEBUG] Arbiter booted
[2026-01-11 13:10:39 +0000] [28] [INFO] Listening at: http://0.0.0.0:8080 (28)
[2026-01-11 13:10:39 +0000] [28] [INFO] Using worker: gthread
[2026-01-11 13:10:39 +0000] [29] [INFO] Booting worker with pid: 29
[2026-01-11 13:10:39 +0000] [28] [DEBUG] 1 workers
<flask_socketio.SocketIO object at 0x7f0cdb4643d0>
26-01-11 13:10:46 - App has started!
Server initialized for threading.
[2026-01-11 12:29:00 +0000] [28] [DEBUG] GET /get-uuid
155.138.254.213 - - [[11/Jan/2026:12:29:00 +0000]] "GET /get-uuid HTTP/1.1" 200 110 0.054831
[2026-01-11 12:29:00 +0000] [28] [DEBUG] Closing connection.

[miguelgrinberg]

The log that you provided shows one successful request to the /get-uuid URL, with response status code 200. It does not show any Socket.IO activity. The Closing connection message is a debugging message from Gunicorn, I do not believe it indicates an issue.