fixing changed behavior with singularity pull

the previous singularity pull used to write to stdout so it would be possible
to see the messages. The current writes completely to stderr, so the default
for the pull function stream should be to return that.

Signed-off-by: vsoch <[email protected]>

Author: vsoch

CHANGELOG.md

@@ -17,6 +17,7 @@ The client here will eventually be released as "spython" (and eventually to
 singularity on pypi), and the versions here will coincide with these releases.
 
 ## [master](https://github.com/singularityhub/singularity-cli/tree/master)
+ - choose output for stream_command (0.0.14)
  - adding support to pull from a url (0.1.13)
  - add more verbosity to instance start/stop (0.1.12)
  - adding more verbosity to running commands (0.1.11)

spython/main/pull.py

@@ -97,7 +97,9 @@ def pull(
 
         # Option 3: A custom name we can predict (not commit/hash) and can also show
         else:
-            return final_image, stream_command(cmd, sudo=False)
+
+            # As of Singularity 3.x (at least 3.8) output goes to stderr
+            return final_image, stream_command(cmd, sudo=False, output_type="stderr")
 
     if os.path.exists(final_image) and not quiet:
         bot.info(final_image)

spython/utils/terminal.py

@@ -110,7 +110,13 @@ def get_installdir():
     return os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
 
 
-def stream_command(cmd, no_newline_regexp="Progess", sudo=False, sudo_options=None):
+def stream_command(
+    cmd,
+    no_newline_regexp="Progess",
+    sudo=False,
+    sudo_options=None,
+    output_type="stdout",
+):
     """stream a command (yield) back to the user, as each line is available.
 
     # Example usage:
@@ -127,14 +133,25 @@ def stream_command(cmd, no_newline_regexp="Progess", sudo=False, sudo_options=No
     sudo_options: string or list of strings that will be passed as options to sudo
 
     """
+    if output_type not in ["stdout", "stderr"]:
+        bot.exit("Invalid output type %s. Must be stderr or stdout." % output_type)
     cmd = _process_sudo_cmd(cmd, sudo, sudo_options)
 
     process = subprocess.Popen(
         cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True
     )
-    for line in iter(process.stdout.readline, ""):
+
+    # Allow the runner to choose streaming output or error
+    stream = process.stdout.readline
+    if output_type == "stderr":
+        stream = process.stderr.readline
+
+    # Stream lines back to the caller
+    for line in iter(stream, ""):
         if not re.search(no_newline_regexp, line):
             yield line
+
+    # If there is an error, raise.
     process.stdout.close()
     return_code = process.wait()
     if return_code:

spython/version.py

@@ -5,7 +5,7 @@
 # with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 
-__version__ = "0.1.13"
+__version__ = "0.1.14"
 AUTHOR = "Vanessa Sochat"
 AUTHOR_EMAIL = "[email protected]"
 NAME = "spython"