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-rw-r--r--guix/build/ruby-build-system.scm103
1 files changed, 103 insertions, 0 deletions
diff --git a/guix/build/ruby-build-system.scm b/guix/build/ruby-build-system.scm
index e3a8111514..a28c47db9d 100644
--- a/guix/build/ruby-build-system.scm
+++ b/guix/build/ruby-build-system.scm
@@ -173,6 +173,109 @@ GEM-FLAGS are passed to the 'gem' invokation, if present."
"Makefile")))))
#t))))
+(define* (wrap-ruby-program prog #:key (gem-clear-paths #t) #:rest vars)
+ "Make a wrapper for PROG. VARS should look like this:
+
+ '(VARIABLE DELIMITER POSITION LIST-OF-DIRECTORIES)
+
+where DELIMITER is optional. ':' will be used if DELIMITER is not given.
+
+For example, this command:
+
+ (wrap-ruby-program \"foo\"
+ '(\"PATH\" \":\" = (\"/gnu/.../bar/bin\"))
+ '(\"CERT_PATH\" suffix (\"/gnu/.../baz/certs\"
+ \"/qux/certs\")))
+
+will copy 'foo' to '.real/fool' and create the file 'foo' with the following
+contents:
+
+ #!location/of/bin/ruby
+ ENV['PATH'] = \"/gnu/.../bar/bin\"
+ ENV['CERT_PATH'] = (ENV.key?('CERT_PATH') ? (ENV['CERT_PATH'] + ':') : '') + '/gnu/.../baz/certs:/qux/certs'
+ load location/of/.real/foo
+
+This is useful for scripts that expect particular programs to be in $PATH, for
+programs that expect particular gems to be in the GEM_PATH.
+
+This is preferable to wrap-program, which uses a bash script, as this prevents
+ruby scripts from being executed with @command{ruby -S ...}.
+
+If PROG has previously been wrapped by 'wrap-ruby-program', the wrapper is
+extended with definitions for VARS."
+ (define wrapped-file
+ (string-append (dirname prog) "/.real/" (basename prog)))
+
+ (define already-wrapped?
+ (file-exists? wrapped-file))
+
+ (define (last-line port)
+ ;; Return the last line read from PORT and leave PORT's cursor right
+ ;; before it.
+ (let loop ((previous-line-offset 0)
+ (previous-line "")
+ (position (seek port 0 SEEK_CUR)))
+ (match (read-line port 'concat)
+ ((? eof-object?)
+ (seek port previous-line-offset SEEK_SET)
+ previous-line)
+ ((? string? line)
+ (loop position line (+ (string-length line) position))))))
+
+ (define (export-variable lst)
+ ;; Return a string that exports an environment variable.
+ (match lst
+ ((var sep '= rest)
+ (format #f "ENV['~a'] = '~a'"
+ var (string-join rest sep)))
+ ((var sep 'prefix rest)
+ (format #f "ENV['~a'] = '~a' + (ENV.key?('~a') ? ('~a' + ENV['~a']) : '')"
+ var (string-join rest sep) var sep var))
+ ((var sep 'suffix rest)
+ (format #f "ENV['~a'] = (ENV.key?('~a') ? (ENV['~a'] + '~a') : '') + '~a'"
+ var var var sep (string-join rest sep)))
+ ((var '= rest)
+ (format #f "ENV['~a'] = '~a'"
+ var (string-join rest ":")))
+ ((var 'prefix rest)
+ (format #f "ENV['~a'] = '~a' + (ENV.key?('~a') ? (':' + ENV['~a']) : '')"
+ var (string-join rest ":") var var))
+ ((var 'suffix rest)
+ (format #f "ENV['~a'] = (ENV.key?('~a') ? (ENV['~a'] + ':') : '') + '~a'"
+ var var var (string-join rest ":")))))
+
+ (if already-wrapped?
+
+ ;; PROG is already a wrapper: add the new "export VAR=VALUE" lines just
+ ;; before the last line.
+ (let* ((port (open-file prog "r+"))
+ (last (last-line port)))
+ (for-each (lambda (var)
+ (display (export-variable var) port)
+ (newline port))
+ vars)
+ (display last port)
+ (close-port port))
+
+ ;; PROG is not wrapped yet: create a shell script that sets VARS.
+ (let ((prog-tmp (string-append wrapped-file "-tmp")))
+ (mkdir-p (dirname prog-tmp))
+ (link prog wrapped-file)
+
+ (call-with-output-file prog-tmp
+ (lambda (port)
+ (format port
+ "#!~a~%~a~%~a~%load '~a'~%"
+ (which "ruby")
+ (string-join (map export-variable vars) "\n")
+ ;; This ensures that if the GEM_PATH has been changed,
+ ;; then that change will be noticed.
+ (if gem-clear-paths "Gem.clear_paths" "")
+ (canonicalize-path wrapped-file))))
+
+ (chmod prog-tmp #o755)
+ (rename-file prog-tmp prog))))
+
(define (log-file-deletion file)
(display (string-append "deleting '" file "' for reproducibility\n")))