How can I pull a specific file into the fileset? - file

Question

I'm writing a library that makes use of a file from a GitHub repository that I don't own:
git init foo
cd foo
git submodule add https://github.com/KhronosGroup/Vulkan-Docs.git github/KhronosGroup/Vulkan-Docs
mkdir -p src/com/example/foo resources/com/example/foo
Here are the other two relevant files in foo.
build.boot:
(set-env!
:resource-paths #{"src" "resources"}
:dependencies '[[adzerk/bootlaces "0.1.13" :scope "test"]])
(require '[adzerk.bootlaces :refer :all])
(deftask run [f function SYM sym]
(with-pass-thru _
(require (symbol (namespace function)))
((resolve function))))
(def +version+ "0.1.0-SNAPSHOT")
(bootlaces! +version+ :dont-modify-paths? true)
(task-options!
pom {:project 'com.example/foo
:version +version+})
src/com/example/foo/core.clj:
(ns com.example.foo.core
(:require [clojure.java.io :as io]))
(defn bar []
(some-> "com/example/foo/spec.xml" io/resource slurp count prn))
What I want is some sort of add task that allows me to do something like this:
boot add --resource --from github/KhronosGroup/Vulkan-Docs/src/spec/vk.xml --to com/example/foo/spec.xml run -f com.example.foo.core/bar
585128
I tried using the -R option of sift, but it has two problems for my use case:
Far more files than just the one I want (vk.xml) are pulled into the fileset, which would bloat the size of my JAR
Because -R simply adds the directory to the set of resource paths, all of its contents are added to the fileset at the top level, which could easily clobber my own resources
Essentially, I want something that has the same effect as the below three commands, but without actually touching the resources directory:
cp github/KhronosGroup/Vulkan-Docs/src/spec/vk.xml resources/com/example/foo/spec.xml
boot build-jar
rm resources/com/example/foo/spec.xml
In other words, the com.example/foo JAR should contain that XML file as a resource, so that resource should be available when I use com.example/foo from another project:
boot -d com.example/foo:0.1.0-SNAPSHOT repl
(require '[com.example.foo.core :as foo])
;;=> nil
(foo/bar)
;; 585128
;;=> nil
How can I pull a specific file (e.g. from a Git submodule) into the fileset at a specific location as a resource, without touching any of the files that I already have in the fileset?