From 0f848f7855f5dfdd6b318a80d7d54aee9fa97614 Mon Sep 17 00:00:00 2001
From: Min RK <benjaminrk@gmail.com>
Date: Thu, 18 Feb 2021 14:34:07 +0100
Subject: [PATCH] handle $R2D_ENTRYPOINT in new entrypoint

---
 repo2docker/buildpacks/repo2docker-entrypoint | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/repo2docker/buildpacks/repo2docker-entrypoint b/repo2docker/buildpacks/repo2docker-entrypoint
index 90645c1e..1ff4dd61 100755
--- a/repo2docker/buildpacks/repo2docker-entrypoint
+++ b/repo2docker/buildpacks/repo2docker-entrypoint
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# note: must run on Python >= 3.5
+# note: must run on Python >= 3.5, which mainly means no f-strings
 
 # goals:
 # - load environment variables from a login shell (bash -l)
@@ -84,8 +84,13 @@ def main():
         "a",
     )
 
+    command = sys.argv[1:]
+    r2d_entrypoint = os.environ.get("R2D_ENTRYPOINT")
+    if r2d_entrypoint:
+        command.insert(0, r2d_entrypoint)
+
     child = subprocess.Popen(
-        sys.argv[1:],
+        command,
         bufsize=1,
         env=env,
         start_new_session=True,