Datapusher URL stays within docker-compose

[riordan]

Summary

This pull request changes the datapusher URL to use docker-compose style networking, so that requests to datapusher are independent of the site url.

Background

First of all - thank you for creating this incredibly well-documented way to set up CKAN. I'd been looking for a way to build a durable CKAN that was easy to reproduce, stored files on S3, and could be easily ported to a new machine without impact.

After I deployed the system following your instructions, CKAN wasn't connecting to datapusher at all. This took a long time to troubleshoot and was manifesting in 504 timeout errors every time we tried to add a new resource to a dataset and nothing entering the datastore.

Then, any resource we added that was hosted on another site was being served through the OKF Dataproxy service on Google, which frequently runs out of free bandwidth, so our data previews failed.

Anyhow, this was when it became clear that something was wrong with the datastore and the datapusher.

It appears this was also the case with prior issue #47 (datapusher isn't talking to other services)

Changes

• rather than using the siteurl environment variable to connect to the datastore (which would have required the AWS security settings to open up the datapusher port), this uses docker-compose style networking to set up the datapusher connection. [e.g. CKAN_DATAPUSHER_URL: "${CKAN_SITE_URL}:8000" -> CKAN_DATAPUSHER_URL: "http://datapusher:8800"
• This also changes the port that datapusher runs on to 8800, to be closer to a stock CKAN configuration.

[riordan]

(original comment updated to reflect an over-eager submission)

[Kyle-Falconer]

Wow thanks for looking into this. I know I spent quite a while on this problem as well and never really figures it out. We will test this and let you know.