boot-clj/boot

Dynamic var to customize env at task creation time

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#468 opened on Jun 2, 2016

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 (8 comments) (0 reactions) (0 assignees)Clojure (1,748 stars) (178 forks)batch import
help wanted

Description

It would be nice to shadow the global env to better separate multiple apps running in the same boot pipeline. This shadowing is only needed at task creation time, not run time.

As discussed in Slack a dynamic var *env* (in boot.pod or boot.core) might be the solution.

;; binding *env* when creating the pipeline
(binding [*env* (get-env)]
  (my-task))

(deftask my-task []
  (fn [next-task]
    ;; bind env outside fileset-receiving fn
    (let [env *env*]
      (fn [fileset]
        (pod/make-pod env ,,,))))

/cc @micha @arichiardi

Contributor guide

Tech stack
None
Domain
build systemtooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Understanding of Clojure dynamic variablesFamiliarity with boot pipeline and namespaces
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue suggests introducing a dynamic var `*env*` in `boot.pod` or `boot.core` to allow shadowing the global env at task creation time. Research the boot source code in the `boot` and `boot.core` namespaces to understand how env is currently bound and used. Review the Slack discussion referenced in the issue for context. The implementation would likely involve defining a dynamic var and binding it in task creation functions, while ensuring backward compatibility.