subprocess_run_octave: for GNU Octave only

Author: scivision

+stdlib/subprocess_run.m

@@ -1,4 +1,5 @@
-%% SUBPROCESS_RUN run process with optional cwd, env. vars, stdin, timeout
+%% SUBPROCESS_RUN run process for Matlab only
+% with optional cwd, env. vars, stdin, timeout
 %
 % handles command lines with spaces
 % input each segment of the command as an element in a string array
@@ -23,7 +24,7 @@
 %
 % NOTE: if cwd option used, any paths must be absolute or relative to cwd.
 % otherwise, they are relative to pwd.
-% SUBPROCESS_RUN run a program with arguments and options
+%
 % uses Matlab Java ProcessBuilder interface to run subprocess and use stdin/stdout pipes
 % https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/ProcessBuilder.html
 

+stdlib/subprocess_run_octave.m

@@ -0,0 +1,162 @@
+%% SUBPROCESS_RUN run process for GNU Octave only
+% with optional cwd, env. vars, stdin, timeout
+%
+% handles command lines with spaces
+% input each segment of the command as an element in a string array
+% this is how python subprocess.run works
+%
+%%% Inputs
+% * cmd_array: cell of char to compose a command line
+% * env: environment variable struct to set
+% * cwd: working directory to use while running command
+% * stdin: string to pass to subprocess stdin pipe
+% * timeout: time to wait for process to complete before erroring (seconds)
+%%% Outputs
+% * status: 0 is generally success. -1 if timeout. Other codes as per the
+% program / command run
+% * stdout: stdout from process
+% * stderr: stderr from process
+%
+%% Example
+% subprocess_run({'mpiexec', '-help2'})
+%
+% NOTE: if cwd option used, any paths must be absolute or relative to cwd.
+% otherwise, they are relative to pwd.
+%
+% uses Java ProcessBuilder interface to run subprocess and use stdin/stdout pipes
+% https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/ProcessBuilder.html
+
+function [status, stdout, stderr] = subprocess_run_octave(cmd, env, cwd, stdin, timeout)
+if ischar(cmd), cmd = {cmd}; end
+if nargin < 2 || isempty(env), env = struct(); end
+if nargin < 3, cwd = ''; end
+if nargin < 4, stdin = ''; end
+if nargin < 5, timeout = 0; end
+
+%% process instantiation
+% https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/ProcessBuilder.html#command(java.lang.String...)
+jcary = javaArray("java.lang.String", length(cmd));
+for i = 1:length(cmd)
+  jcary(i) = javaObject("java.lang.String", cmd{i});
+end
+proc = javaObject("java.lang.ProcessBuilder", jcary);
+
+if ~isempty(fieldnames(env))
+  % https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/ProcessBuilder.html#environment()
+  jenv = proc.environment();
+  fields = fieldnames(env);
+  for i = 1:length(fields)
+    jenv.put(fields{i}, env.(fields{i}));
+    % jenv.put(fields{i}, javaObject("java.lang.String", env.(fields{i})));
+  end
+end
+
+if stdlib.len(cwd) > 0
+  % https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/ProcessBuilder.html#directory(java.io.File)
+  o = javaObject("java.io.File", cwd);
+  proc.directory(o);
+end
+
+%% start process
+% https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/ProcessBuilder.html#start()
+h = proc.start();
+
+%% stdin pipe
+if stdlib.len(stdin) > 0
+  os = javaObject("java.io.OutputStream", h.getOutputStream());
+  writer = javaObject("java.io.BufferedWriter", os);
+  writer.write(stdin);
+  writer.flush()
+  writer.close()
+end
+
+%% wait for process to complete
+% https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/Process.html#waitFor()
+
+tmsg = '';
+if timeout > 0
+  % returns true if process completed successfully
+  % returns false if process did not complete within timeout
+  sec = javaMethod("valueOf", "java.util.concurrent.TimeUnit", "SECONDS");
+  b = h.waitFor(timeout, sec);
+  if b
+    status = 0;
+  else
+    tmsg = 'Subprocess timeout';
+    status = -1;
+  end
+else
+  % returns 0 if process completed successfully
+  status = h.waitFor();
+end
+
+%% read stdout, stderr pipes
+stdout = read_stream(h.getInputStream());
+stderr = read_stream(h.getErrorStream());
+
+%% close process
+h.destroy();
+
+stderr = strcat(tmsg, stderr);
+
+if nargout < 2 && stdlib.len(stdout) > 0
+  disp(stdout)
+end
+if nargout < 3 && stdlib.len(stderr) > 0
+  warning(stderr)
+end
+
+end % function subprocess_run
+
+
+function msg = read_stream(stream)
+
+% https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/io/BufferedReader.html
+reader = javaObject("java.io.BufferedReader", javaObject("java.io.InputStreamReader", stream));
+
+line = reader.readLine();
+msg = '';
+while ~isempty(line)
+  msg = strcat(msg, line, newline);
+
+  line = reader.readLine();
+end
+
+if stdlib.len(msg) > 0 && msg(end) == newline
+  msg(end) = [];
+end
+
+reader.close();
+
+end
+
+%!test
+%! if ispc, c = "dir"; else, c = "ls"; end
+%! [r, m, e] = subprocess_run_octave(c);
+%! assert(r == 0)
+%! assert(length(m) > 0)
+%! assert(length(e) == 0)
+%! [r, mc, e] = subprocess_run_octave(c, [], '/');
+%! assert(r == 0)
+%! assert(!strcmp(m, mc))
+%!testif 0
+%! names = {'TEST1', 'TEST2'};
+%! vals = {'test123', 'test321'};
+%! env = struct(names{1}, vals{1}, names{2}, vals{2});
+%! for i = 1:length(names)
+%!   if ispc
+%!     c = {"cmd", "/c", "echo", strcat('%', names{i}, '%')};
+%!   else
+%!     c = {"echo", strcat('$', names{i})};
+%!   end
+%!   [r, m, e] = subprocess_run_octave(c, env);
+%!   assert(r == 0)
+%!   assert(strcmp(m, vals{i}), '%s != %s', m, vals{i})
+%!   assert(length(e) == 0)
+%! end
+%!test
+%! if ispc, c = {'powershell', '-command', 'Start-Sleep -s 3'}; else, c = {'sleep', '3'}; end
+%! [r, m, e] = subprocess_run_octave(c, [], [], [], 1);
+%! assert(r == -1)
+%! assert(length(m) == 0)
+%! assert(strncmp(e, 'Subprocess timeout', 17))