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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.node.admin.task.util.process;
import com.yahoo.jdisc.Timer;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import static com.yahoo.yolean.Exceptions.uncheck;
/**
* @author hakonhall
*/
public class ProcessFactoryImpl implements ProcessFactory {
private static final Logger logger = Logger.getLogger(ProcessFactoryImpl.class.getName());
private static final File DEV_NULL = new File("/dev/null");
private final ProcessStarter processStarter;
private final Timer timer;
ProcessFactoryImpl(ProcessStarter processStarter, Timer timer) {
this.processStarter = processStarter;
this.timer = timer;
}
@Override
public ChildProcess2Impl spawn(CommandLine commandLine) {
List<String> arguments = commandLine.getArguments();
if (arguments.isEmpty()) {
throw new IllegalArgumentException("No arguments specified - missing program to spawn");
}
ProcessBuilder processBuilder = new ProcessBuilder(arguments);
for (var entry : commandLine.getEnvironmentOverrides().entrySet()) {
if (entry.getValue() == null) {
processBuilder.environment().remove(entry.getKey());
} else {
processBuilder.environment().put(entry.getKey(), entry.getValue());
}
}
if (commandLine.getRedirectStderrToStdoutInsteadOfDiscard()) {
processBuilder.redirectErrorStream(true);
} else {
processBuilder.redirectError(ProcessBuilder.Redirect.to(DEV_NULL));
}
// The output is redirected to a file (temporary or user-defined) because:
// - We could read continuously from process.getInputStream, but that may block
// indefinitely with a faulty program.
// - If we don't read continuously from process.getInputStream, then because
// the underlying channel may be a pipe, the child may be stopped because the pipe
// is full.
// - To honor the timeout, no API can be used that may end up blocking indefinitely.
//
// Therefore, we redirect the output to a file and use waitFor w/timeout. This also
// has the benefit of allowing for inspection of the file during execution, and
// allowing the inspection of the file if it e.g. gets too large to hold in-memory.
FileAttribute<Set<PosixFilePermission>> fileAttribute = PosixFilePermissions.asFileAttribute(
PosixFilePermissions.fromString("rw-------"));
Path outputFile = commandLine.getOutputFile()
.map(file -> {
uncheck(() -> Files.deleteIfExists(file));
uncheck(() -> Files.createFile(file, fileAttribute));
return file;
})
.orElseGet(() -> {
String temporaryFilePrefix =
ProcessFactoryImpl.class.getSimpleName() + "-" + commandLine.programName() + "-";
return uncheck(() -> Files.createTempFile(
temporaryFilePrefix,
".out",
fileAttribute));
});
try {
processBuilder.redirectOutput(outputFile.toFile());
ProcessApi2 process = processStarter.start(processBuilder);
return new ChildProcess2Impl(commandLine, process, outputFile, timer);
} catch (RuntimeException | Error throwable) {
try {
if (commandLine.getOutputFile().isEmpty())
Files.delete(outputFile);
} catch (IOException ioException) {
logger.log(Level.WARNING, "Failed to delete temporary file at " +
outputFile, ioException);
}
throw throwable;
}
}
}
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