Cannot reach port of gcloud appengine devserver - bash

Question

for testing I try to run the gcloud devserver inside docker with that comment:
sudo /usr/local/gcloud/google-cloud-sdk/bin/java_dev_appserver.sh --disable_update_check --port=8888 --help /app/target/qdacity-war/ 2>&1 | sudo tee /app/logs/devserver.log > /dev/null &
To check if the devserver has started successfully, I use this script:
#!/bin/bash
# This script waits until the port 8888 is open.
SERVER=localhost
PORT=8888
TIMEOUT=180
TIME_INTERVAL=2
PORT_OPEN=1
PORT_CLOSED=0
time=0
isPortOpen=0
while [ $time -lt $TIMEOUT ] && [ $isPortOpen -eq $PORT_CLOSED ];
do
# Connect to the port
(echo > /dev/tcp/$SERVER/$PORT) >/dev/null 2>&1
if [ $? -ne 0 ]; then
isPortOpen=$PORT_CLOSED
else
isPortOpen=$PORT_OPEN
fi
time=$(($time+$TIME_INTERVAL))
sleep $TIME_INTERVAL
done
if [ $isPortOpen -eq $PORT_OPEN ]; then
echo "Port is open after ${time} seconds."
# Give the server more time to properly start
sleep 10
else
echo "Reached the timeout (${TIMEOUT} seconds). The port ${SERVER}:${PORT} is not available."
exit 1
fi
After running all the test, I just got back:
Reached the timeout (180 seconds). The port localhost:8888 is not available.
I couldn't find out if there were any problems starting the devserver or querying the port.
Does anyone have an idea or solution?
Thanks!

Answer 1

By default, by only accepting localhost|loopback traffic, you're unable to access the server remotely.
Please try adding --address=0.0.0.0:
(link) to your java_dev_appserver.sh command.
Example
Used a variant of Google's HelloWorld sample.
Ran this with mvn appengine:run (to confirm it works and build the WAR).
Then /path/to/bin/java_dev_appserver.sh ./target/hellofreddie-0.1 (to confirm it works with the local development server).
Then used Google's Cloud SDK container image (link), mounted the previously generated WAR directory into it, and ran the server on :9999:
docker run \
--interactive \
--tty \
--publish=9999:9999 \
--volume=${PWD}/target:/target \
google/cloud-sdk \
/usr/lib/google-cloud-sdk/bin/java_dev_appserver.sh \
--address=0.0.0.0 \
--port=9999 \
./target/hellofreddie-0.1
Am able to curl the endpoint:
curl \
--silent \
--location \
--write-out "%{http_code}" \
--output /dev/null \
localhost:9999
returns 200
And, running your scripts adjusted with PORT=9999 returns:
Port is open after 2 seconds.