PR: more detailed Docker build instructions for developers

[simonmichael]

Here's a non-github PR, adding more detailed docker instructions to the Install page:

https://gitea.evergreencrypto.co/AaronFiore/hledger_site/commit/473d8a332d372361621c385cccf5885668cbe37b

rendered

I believe it might belong there or somewhere more developer oriented. Any thoughts from other docker users ?

[simonmichael]

Commit message:

install: add Developer build from source (with Docker) instructions

This commit provides a more-dynamic approach to using Docker for
hledger development while resolving repo-related issues when building
with Docker.

The resolved issues are as follows:

• The Dockerfile's base image tag is hardcoded; preventing hledger
  development with other ghc versions that are available by image tag.

  • While passing compiler args to stack is an option, since this is
    also hardcoded in the Dockerfile, stack args cannot be passed.

• The current ./docker setup only (theoretically) supports release
  and not development branches; as stack plans are either conflicting
  with the Dockerfile's ghc version or a required stack plan is not
  available (see first comment above).

• hledger{-ui,-web} binary artifacts remain within the image; no
  compose file is available to specify bind-mounts. This then requires
  a user to manually mount the container with every run rather than
  simply drop the binaries into a host-available, bind-mounted
  ./build directory on a 'per-build' run.

Discussion:

Q: how does it differ from the short docker command on the Install page ?

A:

For Docker users who are developers:

• For building: for all the reasons I described in the commit and commit's log (https://gitea.evergreencrypto.co/AaronFiore/hledger_site/commit/473d8a332d372361621c385cccf5885668cbe37b). I spent a fair amount of time making this rationale crystal clear, although it's geared toward seasoned Docker users.
• For using: it's effectively useless (see below).

For Docker users who are relying on ./docker; the current ./docker is extremely limiting in its case:

• Container ports are hardcoded in run script and Dockerfile, despite reading env vars within container (this is an impl issue).
• Only a single journal and single rules file is bind-mounted; any other included/linked journals and/or rules are not bind-mounted nor is there a reasonably effective way to do this with the current ./docker (this is resolved with docker-finance / dfi).
• The number of hledger-web arguments are hardcoded into the container's script with no option for arg expansion.
• There's likely more but I've spent more time looking at it than improving it.

The current ./docker can be re-written to be more flexible but, for advanced Docker users, this one-liner is more realistic for simply getting the binaries into your hands (especially for development). Perhaps the section header could indicate "Advanced" or similar?