1 files changed, 82 insertions, 0 deletions
diff --git a/lib/spack/spack/cmd/common/env_utility.py b/lib/spack/spack/cmd/common/env_utility.py
new file mode 100644
index 0000000000..e3f32737b4
--- /dev/null
+++ b/lib/spack/spack/cmd/common/env_utility.py
@@ -0,0 +1,82 @@
+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+from __future__ import print_function
+
+import argparse
+import os
+
+import llnl.util.tty as tty
+import spack.build_environment as build_environment
+import spack.paths
+import spack.cmd
+import spack.cmd.common.arguments as arguments
+from spack.util.environment import dump_environment, pickle_environment
+
+
+def setup_parser(subparser):
+    arguments.add_common_arguments(subparser, ['clean', 'dirty'])
+    subparser.add_argument(
+        '--dump', metavar="FILE",
+        help="dump a source-able environment to FILE"
+    )
+    subparser.add_argument(
+        '--pickle', metavar="FILE",
+        help="dump a pickled source-able environment to FILE"
+    )
+    subparser.add_argument(
+        'spec', nargs=argparse.REMAINDER,
+        metavar='spec [--] [cmd]...',
+        help="specs of package environment to emulate")
+    subparser.epilog\
+        = 'If a command is not specified, the environment will be printed ' \
+        'to standard output (cf /usr/bin/env) unless --dump and/or --pickle ' \
+        'are specified.\n\nIf a command is specified and spec is ' \
+        'multi-word, then the -- separator is obligatory.'
+
+
+def emulate_env_utility(cmd_name, context, args):
+    if not args.spec:
+        tty.die("spack %s requires a spec." % cmd_name)
+
+    # Specs may have spaces in them, so if they do, require that the
+    # caller put a '--' between the spec and the command to be
+    # executed.  If there is no '--', assume that the spec is the
+    # first argument.
+    sep = '--'
+    if sep in args.spec:
+        s = args.spec.index(sep)
+        spec = args.spec[:s]
+        cmd = args.spec[s + 1:]
+    else:
+        spec = args.spec[0]
+        cmd = args.spec[1:]
+
+    specs = spack.cmd.parse_specs(spec, concretize=True)
+    if len(specs) > 1:
+        tty.die("spack %s only takes one spec." % cmd_name)
+    spec = specs[0]
+
+    build_environment.setup_package(spec.package, args.dirty, context)
+
+    if args.dump:
+        # Dump a source-able environment to a text file.
+        tty.msg("Dumping a source-able environment to {0}".format(args.dump))
+        dump_environment(args.dump)
+
+    if args.pickle:
+        # Dump a source-able environment to a pickle file.
+        tty.msg(
+            "Pickling a source-able environment to {0}".format(args.pickle))
+        pickle_environment(args.pickle)
+
+    if cmd:
+        # Execute the command with the new environment
+        os.execvp(cmd[0], cmd)
+
+    elif not bool(args.pickle or args.dump):
+        # If no command or dump/pickle option then act like the "env" command
+        # and print out env vars.
+        for key, val in os.environ.items():
+            print("%s=%s" % (key, val))