I have been attempting to follow the various instructions and troubleshooting to get a docker container to connect to another docker container running local dynamodb via boto3. References/troubleshooting so far:
- In compose, can just use automatic linking. Incidentally I tried explicitly specifying a shared network but could not succeed this way.
- Make sure to use the resource name from compose, not localhost
- Github repo with a template
Dockerfile (docker build -t min-example:latest .):
FROM python:3.8
RUN pip install boto3
RUN mkdir /app
COPY min_example.py /app
WORKDIR /app
Docker compose (min-example.yml):
version: "3.3"
services:
db:
container_name: db
image: amazon/dynamodb-local
ports:
- "8000:8000"
app:
image: min-example:latest
container_name: app
depends_on:
- db
min_example.py
import boto3
if __name__ == '__main__':
ddb = boto3.resource('dynamodb',
endpoint_url='http://db:8000',
region_name='dummy',
aws_access_key_id='dummy',
aws_secret_access_key='dummy')
existing_tables = [t.name for t in list(ddb.tables.all())]
print(existing_tables)
existing_tables = [t.name for t in list(ddb.tables.all())]
print(existing_tables)
Run with
docker-compose run -f min-example.yml app python min_example.py
It hangs on the ddb.tables.all() call, and times out with the error:
botocore.exceptions.ReadTimeoutError: Read timeout on endpoint URL: "http://db:8000/"
Interestingly, I can curl:
docker-compose -f min-example.yml run app curl http://db:8000/
{"__type":"com.amazonaws.dynamodb.v20120810#MissingAuthenticationToken","message":"Request must contain either a valid (registered) AWS access key ID or X.509 certificate."}
Which suggests the containers can communicate.
