Merge pull request #987 from betatim/stream-logs

[MRG] Stream jupyter server logs to a file

Author: manics

repo2docker/buildpacks/repo2docker-entrypoint

@@ -2,11 +2,23 @@
 # lightest possible entrypoint that ensures that
 # we use a login shell to get a fully configured shell environment
 # (e.g. sourcing /etc/profile.d, ~/.bashrc, and friends)
+
+# Setup a file descriptor (FD) that is connected to a tee process which
+# writes its input to $REPO_DIR/.jupyter-server-log.txt
+# We later use this FD as a place to redirect the output of the actual
+# command to. We can't add `tee` to the command directly as that will prevent
+# the container from exiting when `docker stop` is run.
+# See https://stackoverflow.com/a/55678435
+exec {log_fd}> >(exec tee $REPO_DIR/.jupyter-server-log.txt)
+
 if [[ ! -z "${R2D_ENTRYPOINT:-}" ]]; then
     if [[ ! -x "$R2D_ENTRYPOINT" ]]; then
         chmod u+x "$R2D_ENTRYPOINT"
     fi
-    exec "$R2D_ENTRYPOINT" "$@"
+    exec "$R2D_ENTRYPOINT" "$@" >&"$log_fd"
 else
-    exec "$@"
+    exec "$@" >&"$log_fd"
 fi
+
+# Close the logging output again
+#exec {log_fd}>&-

tests/unit/test_env.py

@@ -58,6 +58,10 @@ def test_env():
 
     # all docker output is returned by repo2docker on stderr
     # extract just the declare for better failure message formatting
+    # stdout should be empty
+    assert not result.stdout
+
+    # stderr should contain lines of output
     declares = [x for x in result.stderr.split("\n") if x.startswith("declare")]
     assert 'declare -x FOO="{}"'.format(ts) in declares
     assert 'declare -x BAR="baz"' in declares