I would like to run a hidden script file that resides in the current location using process builder. with the following code
// System.out.println("line"+reader.readLine());
ProcessBuilder builder = new ProcessBuilder(shfile.getAbsolutePath());
builder.redirectErrorStream(true);
Process process = builder.start();
BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()));
String output = null;
System.out.println("out"); //===printing this
while (null != (output = br.readLine()))
{
System.out.println("in"); //not printing this
System.out.println(">>"+output);
}
int rs = process.waitFor();
but it hangs in the br.readline()..
but when I run the same script file using the following command in terminal
sh .script.sh
it executes and gives me the expected results
I looked into all the loops in the forum everyone asks to handle input stream and error stream in threads or do a redirect error stream. I have added a redirect error stream but still it hangs.
when i press ctrl+c it prints the initial lines of the output and exits.
Content of my script file
#!/bin/sh
cd /home/ats/cloudripper/lke_factory_asb_v2/lk_assets_factory_release/
sh ./LKE_run_Diablo.sh 0a0e0c3dc893
So how to handle this situation.
Process builder have special API to redirect child process input, output and error streams. See documentation
If you need both child and parent process to use same console you should use INHERIT mode redirection. An example:
public class ChildProcessOutputProxy {
public static void main(String[] args) {
ProcessBuilder builder = new ProcessBuilder("whoami");
builder.redirectOutput(Redirect.INHERIT);
builder.redirectErrorStream(true);
try {
var child = builder.start();
child.waitFor();
} catch (IOException e) {
System.err.println(e.getMessage());
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}
I have the following problem which seems to be caused by the "docker pull" in my shell script, as the pull works concurrently
#!/bin/bash
#VARIABLES
NAME="my-app"
IMAGE="my-image:latest"
#DOCKER
docker stop $NAME
docker rm $NAME
docker pull -q $IMAGE
docker run --name $NAME -d -p 1234:8080 --log-opt fluentd-address=localhost:2233 $IMAGE
Running the script through the terminal works just fine everything works as expected. But when I run it with the Java's ProcessBuilder the script exits much quicker and it seems that it skips the "docker pull" step. As i am not a Java developer and I am not very well familiar with the Language I have the feeling that is something related to the multi-concurrent nature of the docker pull command and the way how the Java Process Builder executes the shell script
The Java class that runs the shell script is this
try {
Collection<Task> tasks = taskService.getProjectTasksByProjectKey(projectId);
Task findTask = findTaskByTaskId(tasks, taskId);
if (findTask.getTaskId() != null) {
ProcessBuilder pb = new ProcessBuilder(findTask.getCmdPath());
Process process = pb.start();
String output;
try (InputStream in = process.getInputStream();
InputStream err = process.getErrorStream();
OutputStream closeOnly = process.getOutputStream()) {
while (process.isAlive()) {
long skipped = in.skip(in.available())
+ err.skip(err.available());
if(skipped == 0L) {
process.waitFor(5L, TimeUnit.MILLISECONDS);
}
}
output = loadStream(in);
} finally {
process.destroy();
}
// String error = loadStream(process.getErrorStream());
// int rc = process.waitFor();
// log.debug("exit code ->>> " + rc);
// StringBuilder output = new StringBuilder();
// BufferedReader reader = new BufferedReader(
// new InputStreamReader(process.getInputStream()));
//
// String line;
//
// while ((line = reader.readLine()) != null) {
// output.append(line + "\n");
// }
//
// int exitVal = process.waitFor();
// if (exitVal == 0) {
// System.out.println(output);
//
// return output.toString();
// } else {
// //abnormal...
// }
return output;
}
else {
throw new InvalidTaskModelException(taskId);
}
} catch (InvalidModelException e) {
throw new InvalidModelException(projectId);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private static String loadStream(InputStream s) throws Exception
{
BufferedReader br = new BufferedReader(new InputStreamReader(s));
StringBuilder sb = new StringBuilder();
String line;
while((line=br.readLine()) != null)
sb.append(line).append("\n");
return sb.toString();
}
The commented lines are different ways I tried to do it.
If anyone encountered a similar problem any help would be much appreciated!
It is good that you already take care for the processes' STDOUT and STDIN. But rather than skipping copy them to System.out so you can see what is going on. I suspect something is not going as per your expectations.
Looking at the bash script you posted and the fact you are trying to run several processes: Is it possible your java code is running the bash script line by line? Be aware your java program it is not a BASH interpreter, so e.g. variable substitution should not work.
why you can not run each command in thread and joins them so that unless therad 1 is not completed . next thread can not start .
also please add command to verify image is downloaded successfully
docker pull -q $IMAGE
docker images | grep $IMAGE
docker run --name $NAME -d -p 1234:8080 --log-opt fluentd-address=localhost:2233 $IMAGE
i am guessing there are 2 possiblities are here
Check local directory persmission if possible give 755 permission to
it .
Java process itself is not able to execute docker command due
to permission issue, run process as sudo user.
Heere is the code I have so far. How do I have miktex-pdftex run?
List<String> processes = new ArrayList<String>();
processes.add("miktex-pdftex --output-directory=[Directory] [file_name].tex");
ProcessBuilder processbuild = new ProcessBuilder(processes);
First, you need to make sure the command you are using actually works at the command. If it does not, then it's not going to work in Java.
Next, one of the main reasons for using ProcessBuilder is to deals with spaces in the command/parameters better then Runtime#exec.
String command = "/Applications/MiKTeX Console.app/Contents/bin/miktex-pdftex";
String outputDir = System.getProperty("user.dir");
String sourceFile = "Sample.tex";
List<String> commands = new ArrayList<>();
commands.add(command);
commands.add("--interaction=nonstopmode");
commands.add("--output-directory=" + outputDir);
commands.add(sourceFile);
So the above is very simple...
The command I want to run is /Applications/MiKTeX Console.app/Contents/bin/miktex-pdftex (I'm running on MacOS and I couldn't get the command installed outside the application bundle)
I want the output-directory to be the same as the current working directory (System.getProperty("user.dir")), but you could supply what every you need
I'm running in "nonstopmode" (--interaction=nonstopmode) because otherwise I would be required to provide input, which is just more complex
And my input file (Sample.tex) which is also in the working directory.
Next, we build the ProcessBuilder and redirect the error stream into the InputStream, this just reduces the next to read these two streams separately...
ProcessBuilder pb = new ProcessBuilder(commands);
pb.redirectErrorStream(true);
Next, we run the command, read the contents of the InputStream (otherwise you can stall the process), you can do what ever you want with this, I've just echoed it to the screen
try {
Process process = pb.start();
InputStream is = process.getInputStream();
int in = -1;
while ((in = is.read()) != -1) {
System.out.print((char)in);
}
int exitValue = process.waitFor();
System.out.println("");
System.out.println("Did exit with " + exitValue);
} catch (IOException | InterruptedException ex) {
ex.printStackTrace();
}
The use int exitValue = process.waitFor(); here is just to ensure that command has completed and get the exit value it generated. Normally, 0 is success, but you'd need to read the documentation of the command to be sure
I am trying to execute this command sort --field-separator="," --key=2 /home/dummy/Desktop/sample.csv" -o /home/dummy/Desktop/sample_temp.csv using Java Runtime and ProcessBuilder.
Manually I am able to execute this command in linux, but using Runtime or ProcessBuilder, this command does not execute. It returns with an error code = 2.
Edit:
If I am trying to execute 'ls' command in linux through Java, I get the list of files in the current directory. But, If I try to execute the command 'ls | grep a', an IOException is thrown with error code=2.
Here is the snippet:
public static void main(String[] args) throws IOException {
InputStream is = null;
ByteArrayOutputStream baos = null;
ProcessBuilder pb = new ProcessBuilder("ls | grep a");
try {
Process prs = pb.start();
is = prs.getInputStream();
byte[] b = new byte[1024];
int size = 0;
baos = new ByteArrayOutputStream();
while((size = is.read(b)) != -1){
baos.write(b, 0, size);
}
System.out.println(new String(baos.toByteArray()));
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try {
if(is != null) is.close();
if(baos != null) baos.close();
} catch (Exception ex){}
}
}
There could be a range of issue with your code. Hence you did not supply your code I can only guess.
The output file needs to be already created
The ',' field separator does not need the quotes around it (see code below)
So after these 2 issues (both making the program exit with '2'), this code actually works:
import java.io.IOException;
import java.util.Arrays;
public class Test {
public static void main(String[] args) throws IOException, InterruptedException {
ProcessBuilder pb = new ProcessBuilder(Arrays.asList("sort", "--field-separator=,", "--key=2", "/tmp/sample.csv", "-o",
"/tmp/sample_temp.csv"));
Process p = pb.start();
int returnCode = p.waitFor();
System.out.println(returnCode);
}
}
Will print '0' and will sort the file correctly.
For the 'ls | grep' issue, read this great article: http://www.javaworld.com/article/2071275/core-javahen-runtime-exec---won-t/core-java/when-runtime-exec---won-t.html
The article basically explains that the Runtime.exec (and the ProcessBuilder wrapper) is for running processes and not a Shell (the ls | grep you are trying are actually 2 processes in Linux communicating with each other thru stdout/in).
I am able to execute that manually. And error code 2 means Misuse of Shell BuiltIns
I see in your example you are only invoking "ls", not "/usr/bin/ls" (or something like that).
When you execute manually you have the luxury of PATH environment variable which is not availabled to the process you create.
Use "which ls" to discover the location of 'ls' on your target system. For your code to be portable you will have to make it a configurable option.
this is the way to execute any bash commands like sort, ls, cat (with sub-options). Please find the snippet:
private String executeCommand(String command) {
StringBuffer output = new StringBuffer();
Process p;
try {
p = Runtime.getRuntime().exec("script.sh");
p.waitFor();
BufferedReader reader =
new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";
while ((line = reader.readLine())!= null) {
output.append(line + "\n");
}
} catch (Exception e) {
e.printStackTrace();
}
return output.toString();
}
In the exec() method, I passed a shell script which contains the bash command within it. That linux command will be executed and you can carry on with the next task. Hope this was helpful.
It is quite simple to run a Unix command from Java.
Runtime.getRuntime().exec(myCommand);
But is it possible to run a Unix shell script from Java code? If yes, would it be a good practice to run a shell script from within Java code?
You should really look at Process Builder. It is really built for this kind of thing.
ProcessBuilder pb = new ProcessBuilder("myshellScript.sh", "myArg1", "myArg2");
Map<String, String> env = pb.environment();
env.put("VAR1", "myValue");
env.remove("OTHERVAR");
env.put("VAR2", env.get("VAR1") + "suffix");
pb.directory(new File("myDir"));
Process p = pb.start();
You can use Apache Commons exec library also.
Example :
package testShellScript;
import java.io.IOException;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
public class TestScript {
int iExitValue;
String sCommandString;
public void runScript(String command){
sCommandString = command;
CommandLine oCmdLine = CommandLine.parse(sCommandString);
DefaultExecutor oDefaultExecutor = new DefaultExecutor();
oDefaultExecutor.setExitValue(0);
try {
iExitValue = oDefaultExecutor.execute(oCmdLine);
} catch (ExecuteException e) {
System.err.println("Execution failed.");
e.printStackTrace();
} catch (IOException e) {
System.err.println("permission denied.");
e.printStackTrace();
}
}
public static void main(String args[]){
TestScript testScript = new TestScript();
testScript.runScript("sh /root/Desktop/testScript.sh");
}
}
For further reference, An example is given on Apache Doc also.
I think you have answered your own question with
Runtime.getRuntime().exec(myShellScript);
As to whether it is good practice... what are you trying to do with a shell script that you cannot do with Java?
I would say that it is not in the spirit of Java to run a shell script from Java. Java is meant to be cross platform, and running a shell script would limit its use to just UNIX.
With that said, it's definitely possible to run a shell script from within Java. You'd use exactly the same syntax you listed (I haven't tried it myself, but try executing the shell script directly, and if that doesn't work, execute the shell itself, passing the script in as a command line parameter).
Yes it is possible to do so. This worked out for me.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import org.omg.CORBA.portable.InputStream;
public static void readBashScript() {
try {
Process proc = Runtime.getRuntime().exec("/home/destino/workspace/JavaProject/listing.sh /"); //Whatever you want to execute
BufferedReader read = new BufferedReader(new InputStreamReader(
proc.getInputStream()));
try {
proc.waitFor();
} catch (InterruptedException e) {
System.out.println(e.getMessage());
}
while (read.ready()) {
System.out.println(read.readLine());
}
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
Here is my example. Hope it make sense.
public static void excuteCommand(String filePath) throws IOException{
File file = new File(filePath);
if(!file.isFile()){
throw new IllegalArgumentException("The file " + filePath + " does not exist");
}
if(isLinux()){
Runtime.getRuntime().exec(new String[] {"/bin/sh", "-c", filePath}, null);
}else if(isWindows()){
Runtime.getRuntime().exec("cmd /c start " + filePath);
}
}
public static boolean isLinux(){
String os = System.getProperty("os.name");
return os.toLowerCase().indexOf("linux") >= 0;
}
public static boolean isWindows(){
String os = System.getProperty("os.name");
return os.toLowerCase().indexOf("windows") >= 0;
}
Yes, it is possible and you have answered it! About good practises, I think it is better to launch commands from files and not directly from your code. So you have to make Java execute the list of commands (or one command) in an existing .bat, .sh , .ksh ... files.
Here is an example of executing a list of commands in a file MyFile.sh:
String[] cmd = { "sh", "MyFile.sh", "\pathOfTheFile"};
Runtime.getRuntime().exec(cmd);
To avoid having to hardcode an absolute path, you can use the following method that will find and execute your script if it is in your root directory.
public static void runScript() throws IOException, InterruptedException {
ProcessBuilder processBuilder = new ProcessBuilder("./nameOfScript.sh");
//Sets the source and destination for subprocess standard I/O to be the same as those of the current Java process.
processBuilder.inheritIO();
Process process = processBuilder.start();
int exitValue = process.waitFor();
if (exitValue != 0) {
// check for errors
new BufferedInputStream(process.getErrorStream());
throw new RuntimeException("execution of script failed!");
}
}
As for me all things must be simple.
For running script just need to execute
new ProcessBuilder("pathToYourShellScript").start();
The ZT Process Executor library is an alternative to Apache Commons Exec. It has functionality to run commands, capturing their output, setting timeouts, etc.
I have not used it yet, but it looks reasonably well-documented.
An example from the documentation: Executing a command, pumping the stderr to a logger, returning the output as UTF8 string.
String output = new ProcessExecutor().command("java", "-version")
.redirectError(Slf4jStream.of(getClass()).asInfo())
.readOutput(true).execute()
.outputUTF8();
Its documentation lists the following advantages over Commons Exec:
Improved handling of streams
Reading/writing to streams
Redirecting stderr to stdout
Improved handling of timeouts
Improved checking of exit codes
Improved API
One liners for quite complex use cases
One liners to get process output into a String
Access to the Process object available
Support for async processes ( Future )
Improved logging with SLF4J API
Support for multiple processes
This is a late answer. However, I thought of putting the struggle I had to bear to get a shell script to be executed from a Spring-Boot application for future developers.
I was working in Spring-Boot and I was not able to find the file to be executed from my Java application and it was throwing FileNotFoundFoundException. I had to keep the file in the resources directory and had to set the file to be scanned in pom.xml while the application was being started like the following.
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
<includes>
<include>**/*.xml</include>
<include>**/*.properties</include>
<include>**/*.sh</include>
</includes>
</resource>
</resources>
After that I was having trouble executing the file and it was returning error code = 13, Permission Denied. Then I had to make the file executable by running this command - chmod u+x myShellScript.sh
Finally, I could execute the file using the following code snippet.
public void runScript() {
ProcessBuilder pb = new ProcessBuilder("src/main/resources/myFile.sh");
try {
Process p;
p = pb.start();
} catch (IOException e) {
e.printStackTrace();
}
}
Hope that solves someone's problem.
Here is an example how to run an Unix bash or Windows bat/cmd script from Java. Arguments can be passed on the script and output received from the script. The method accepts arbitrary number of arguments.
public static void runScript(String path, String... args) {
try {
String[] cmd = new String[args.length + 1];
cmd[0] = path;
int count = 0;
for (String s : args) {
cmd[++count] = args[count - 1];
}
Process process = Runtime.getRuntime().exec(cmd);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
try {
process.waitFor();
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
while (bufferedReader.ready()) {
System.out.println("Received from script: " + bufferedReader.readLine());
}
} catch (Exception ex) {
System.out.println(ex.getMessage());
System.exit(1);
}
}
When running on Unix/Linux, the path must be Unix-like (with '/' as separator), when running on Windows - use '\'. Hier is an example of a bash script (test.sh) that receives arbitrary number of arguments and doubles every argument:
#!/bin/bash
counter=0
while [ $# -gt 0 ]
do
echo argument $((counter +=1)): $1
echo doubling argument $((counter)): $(($1+$1))
shift
done
When calling
runScript("path_to_script/test.sh", "1", "2")
on Unix/Linux, the output is:
Received from script: argument 1: 1
Received from script: doubling argument 1: 2
Received from script: argument 2: 2
Received from script: doubling argument 2: 4
Hier is a simple cmd Windows script test.cmd that counts number of input arguments:
#echo off
set a=0
for %%x in (%*) do Set /A a+=1
echo %a% arguments received
When calling the script on Windows
runScript("path_to_script\\test.cmd", "1", "2", "3")
The output is
Received from script: 3 arguments received
It is possible, just exec it as any other program. Just make sure your script has the proper #! (she-bang) line as the first line of the script, and make sure there are execute permissions on the file.
For example, if it is a bash script put #!/bin/bash at the top of the script, also chmod +x .
Also as for if it's good practice, no it's not, especially for Java, but if it saves you a lot of time porting a large script over, and you're not getting paid extra to do it ;) save your time, exec the script, and put the porting to Java on your long-term todo list.
I think with
System.getProperty("os.name");
Checking the operating system on can manage the shell/bash scrips if such are supported.
if there is need to make the code portable.
String scriptName = PATH+"/myScript.sh";
String commands[] = new String[]{scriptName,"myArg1", "myArg2"};
Runtime rt = Runtime.getRuntime();
Process process = null;
try{
process = rt.exec(commands);
process.waitFor();
}catch(Exception e){
e.printStackTrace();
}
Just the same thing that Solaris 5.10 it works like this ./batchstart.sh there is a trick I don´t know if your OS accept it use \\. batchstart.sh instead. This double slash may help.
for linux use
public static void runShell(String directory, String command, String[] args, Map<String, String> environment)
{
try
{
if(directory.trim().equals(""))
directory = "/";
String[] cmd = new String[args.length + 1];
cmd[0] = command;
int count = 1;
for(String s : args)
{
cmd[count] = s;
count++;
}
ProcessBuilder pb = new ProcessBuilder(cmd);
Map<String, String> env = pb.environment();
for(String s : environment.keySet())
env.put(s, environment.get(s));
pb.directory(new File(directory));
Process process = pb.start();
BufferedReader inputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
BufferedWriter outputReader = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
BufferedReader errReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
int exitValue = process.waitFor();
if(exitValue != 0) // has errors
{
while(errReader.ready())
{
LogClass.log("ErrShell: " + errReader.readLine(), LogClass.LogMode.LogAll);
}
}
else
{
while(inputReader.ready())
{
LogClass.log("Shell Result : " + inputReader.readLine(), LogClass.LogMode.LogAll);
}
}
}
catch(Exception e)
{
LogClass.log("Err: RunShell, " + e.toString(), LogClass.LogMode.LogAll);
}
}
public static void runShell(String path, String command, String[] args)
{
try
{
String[] cmd = new String[args.length + 1];
if(!path.trim().isEmpty())
cmd[0] = path + "/" + command;
else
cmd[0] = command;
int count = 1;
for(String s : args)
{
cmd[count] = s;
count++;
}
Process process = Runtime.getRuntime().exec(cmd);
BufferedReader inputReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
BufferedWriter outputReader = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
BufferedReader errReader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
int exitValue = process.waitFor();
if(exitValue != 0) // has errors
{
while(errReader.ready())
{
LogClass.log("ErrShell: " + errReader.readLine(), LogClass.LogMode.LogAll);
}
}
else
{
while(inputReader.ready())
{
LogClass.log("Shell Result: " + inputReader.readLine(), LogClass.LogMode.LogAll);
}
}
}
catch(Exception e)
{
LogClass.log("Err: RunShell, " + e.toString(), LogClass.LogMode.LogAll);
}
}
and for usage;
ShellAssistance.runShell("", "pg_dump", new String[]{"-U", "aliAdmin", "-f", "/home/Backup.sql", "StoresAssistanceDB"});
OR
ShellAssistance.runShell("", "pg_dump", new String[]{"-U", "aliAdmin", "-f", "/home/Backup.sql", "StoresAssistanceDB"}, new Hashmap<>());