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stdout/stderr routing is now 'virtually' async

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This commit is contained in:
Chris Punches
2021-04-03 20:24:22 -04:00
parent 199d93a2b2
commit 3d421b1ca0
4 changed files with 121 additions and 440 deletions
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132
src/Sproc/Sproc.cpp
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@@ -294,59 +294,96 @@ int Sproc::execute(std::string shell, std::string environment_file, std::string
char stdout_buf[1000] = {0};
char stderr_buf[1000] = {0};
std::cout.flush();
std::cerr.flush();
bool set_break = false;
// read from fd until child completes
while (! set_break ) {
ssize_t stdout_count = read(child_stdout_pipe[READ_END], stdout_buf, sizeof(stdout_buf) - 1);
// will contain a set of file descriptors to monitor representing stdout and stderr of the child process
fd_set readfds;
// cycle through STDOUT
switch (stdout_count) {
case READ_PIPEOPEN_O_NONBLOCK:
if (errno == EINTR) {
continue;
} else {
perror("read");
slog.log(E_FATAL, "PIPE ISSUE with STDOUT");
exit(1);
// loop completion flags
bool set_stdout_break = false;
bool set_stderr_break = false;
// read from fd until child completes -- signaled by stdout_break and stderr_break flags
while ((! set_stderr_break ) or (! set_stdout_break)) {
// clear it out to make sure it's clean
FD_ZERO( & readfds );
// add child stdout and stderr pipes (read end)
FD_SET( child_stdout_pipe[READ_END], & readfds );
FD_SET( child_stderr_pipe[READ_END], & readfds );
int highest_fd = child_stderr_pipe[READ_END] > child_stdout_pipe[READ_END] ? child_stderr_pipe[READ_END] : child_stdout_pipe[READ_END];
if ( select( highest_fd + 1, &readfds, NULL, NULL, NULL ) >= 0 )
{ // can read any
if ( FD_ISSET( child_stdout_pipe[READ_END], &readfds ) )
{
// can read child stdout pipe
// so do so
// read and return the byte size of what was read
int stdout_count = read(child_stdout_pipe[READ_END], stdout_buf, sizeof(stdout_buf) - 1);
// switch on the count size to allow for error return handling
switch(stdout_count) {
case READ_PIPEOPEN_O_NONBLOCK:
if ( errno == EINTR ) {
continue;
} else {
perror("read stdout");
slog.log(E_FATAL, "PIPE ISSUE with STDOUT");
exit(1);
}
case READ_EOF:
// signal that STDOUT is complete
set_stdout_break = true;
break;
default:
tee_out.write( stdout_buf, stdout_count );
tee_out.flush();
// clear the buffer to prevent artifacts from previous loop
memset( &stdout_buf[0], 0, sizeof( stdout_buf ) -1 );
}
case READ_EOF:
set_break = true;
break;
default:
tee_out.write(stdout_buf, stdout_count);
tee_out.flush();
memset(&stdout_buf[0], 0, sizeof(stdout_buf));
// END SWITCH
}
}
if ( FD_ISSET( child_stderr_pipe[READ_END], & readfds ) ) {
// can read child stderr pipe
// so do so
// read and return the byte size of what was read
int stderr_count = read( child_stderr_pipe[READ_END], stderr_buf, sizeof( stderr_buf ) -1 );
// switch on the count size to allow for error return handling
switch( stderr_count ) {
case READ_RESULTS::READ_PIPEOPEN_O_NONBLOCK:
if ( errno == EINTR ) {
continue;
} else {
perror( "read stderr" );
slog.log( E_FATAL, "PIPE ISSUE WITH STDERR" );
exit(1);
}
case READ_RESULTS::READ_EOF:
set_stderr_break = true;
//break;
continue;
default:
tee_err.write( stderr_buf, stderr_count );
tee_err.flush();
// clear the buffer to prevent artifacts from previous loop
memset( &stderr_buf[0], 0, sizeof( stderr_buf ) -1 );
}
}
} else {
// select error, fatal, throw
slog.log( E_FATAL, "Fatal error, Unknown.");
} // end select/if
}
set_break = false;
while(! set_break ) {
ssize_t stderr_count = read(child_stderr_pipe[READ_END], stderr_buf, sizeof(stderr_buf) - 1 );
switch ( stderr_count )
{
case READ_PIPEOPEN_O_NONBLOCK:
if (errno == EINTR) {
continue;
} else {
perror("read");
slog.log( E_FATAL, "PIPE ISSUE with STDERR" );
exit(1);
}
case READ_EOF:
set_break = true;
break;
default:
tee_err.write( stderr_buf, stderr_count );
tee_err.flush();
memset(&stderr_buf[0], 0, sizeof(stderr_buf));
// END SWITCH
}
}
while ((pid = waitpid(pid, &exit_code_raw, 0)) == -1) {}
//waitpid( pid, &exit_code_raw, 0 );
@@ -356,6 +393,5 @@ int Sproc::execute(std::string shell, std::string environment_file, std::string
stderr_log.close();
}
}
return WEXITSTATUS( exit_code_raw );
}