I have a simple Python program using pandas_profiling. Here is the source code, which I have stored as c:\temp\pandas_profiling_demo.py:
import pandas as pd
import pandas_profiling as pp
df = pd.DataFrame(data={'x': [1, 2, 3, 4, 5], 'y': [2, 2, 4, 6, 6], 'z': [4, 6, 1, 5, 2]})
print(df.head(10))
profile = pp.ProfileReport(df)
profile.to_file(outputfile="C:\\temp\\pandas_profiling_demo.html")
print("Done.")
I also have a Java program which starts the Python program (this isn't the real program, which involves a GUI, but this will recreate the problem.) My program is in Eclipse, but I will copy it here:
package pandasprofilingbug;
import java.io.File;
import java.lang.ProcessBuilder.Redirect;
import java.nio.file.Files;
import java.util.Map;
public class PandasProfilingBug {
public static void main(String[] args)
{
String[] command = new String[] { "cmd", "/C", "python", "c:\\temp\\pandas_profiling_demo.py" } ;
ProcessBuilder pb = new ProcessBuilder(command);
Map<String, String> env = pb.environment();
env.remove("PYSPARK_DRIVER_PYTHON"); // else attempts to open in notebook environment
Process p = null;
try
{
File log = new File("c:\\temp\\pandas_profiling_demo.log");
Files.deleteIfExists(log.toPath());
pb.redirectErrorStream(true);
pb.redirectOutput(Redirect.to(log));
// System.out.print("Start...");
p = pb.start();
assert pb.redirectInput() == Redirect.PIPE;
assert pb.redirectOutput().file() == log;
assert p.getInputStream().read() == -1;
// TODO: How to give user an option to cancel???
// TODO: How to provide progress report?
System.out.print("Waiting...");
p.waitFor();
System.out.print("waiting over...exitValue = " + p.exitValue());
}
catch (Exception ie)
{
System.err.println(ie);
ie.printStackTrace();
}
}
When I run the Java program, it gets stuck in a loop. Here is the first block of repeated output:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 105, in spawn_main
exitcode = _main(fd)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 114, in _main
prepare(preparation_data)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 225, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
run_name="__mp_main__")
File "C:\Users\bill_\Anaconda3\lib\runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
File "C:\Users\bill_\Anaconda3\lib\runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "C:\Users\bill_\Anaconda3\lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "c:\temp\pandas_profiling_demo.py", line 21, in <module>
profile = pp.ProfileReport(df)
File "C:\Users\bill_\Anaconda3\lib\site-packages\pandas_profiling\__init__.py", line 66, in __init__
description_set = describe(df, **kwargs)
File "C:\Users\bill_\Anaconda3\lib\site-packages\pandas_profiling\describe.py", line 349, in describe
pool = multiprocessing.Pool(pool_size)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\context.py", line 119, in Pool
context=self.get_context())
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\pool.py", line 174, in __init__
self._repopulate_pool()
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\pool.py", line 239, in _repopulate_pool
w.start()
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\process.py", line 105, in start
self._popen = self._Popen(self)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\context.py", line 322, in _Popen
return Popen(process_obj)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\popen_spawn_win32.py", line 33, in __init__
prep_data = spawn.get_preparation_data(process_obj._name)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
_check_not_importing_main()
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
is not going to be frozen to produce an executable.''')
RuntimeError:
An attempt has been made to start a new process before the
current process has finished its bootstrapping phase.
This probably means that you are not using fork to start your
child processes and you have forgotten to use the proper idiom
in the main module:
if __name__ == '__main__':
freeze_support()
...
The "freeze_support()" line can be omitted if the program
is not going to be frozen to produce an executable.
x y z
0 1 2 4
1 2 2 6
2 3 4 1
3 4 6 5
4 5 6 2
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 105, in spawn_main
exitcode = _main(fd)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 114, in _main
prepare(preparation_data)
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 225, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "C:\Users\bill_\Anaconda3\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
run_name="__mp_main__")
# REPEATED AD NAUSEUM
When I run the Python program in a Jupyter notebook, it works fine, creating the desired html file.
When I comment out these lines, it works fine (displays data frame) when called from Java:
#profile = pp.ProfileReport(df)
#profile.to_file(outputfile="C:\\temp\\pandas_profiling_demo.html")
Since I can run the program from Java if the profiling is not used, I suspect there is an issue with pandas_profiling (or at least there is for me.) Why would it cause the program to go into a loop?
Thanks in advance.
