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WFCORE-7623: signal if input is idle #6860

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WFCORE-7623: signal if input is idle #6860

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39 changes: 26 additions & 13 deletions .../shared/src/main/java/org/jboss/as/test/integration/management/cli/CliProcessWrapper.java
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ public CliProcessWrapper(boolean modular){
private Process cliProcess;
private volatile StringBuffer cliOutputBuffer = new StringBuffer();
private BufferedWriter bufferedWriter = null;
private boolean idleInput = false;

@yersan yersan Jul 24, 2026

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This variable must be volatile, otherwise there will not be visibility guarantees between the three threads that modify/read it


/**
* Clear current output buffer
Expand Down Expand Up @@ -178,7 +179,7 @@ public void destroyProcess() {
*/
public String getCurrentPrompt(){
if(cliOutputBuffer.toString().contains("\n")) {
return cliOutputBuffer.toString().substring(cliOutputBuffer.toString().lastIndexOf("\n")+1);
return cliOutputBuffer.substring(cliOutputBuffer.toString().lastIndexOf("\n")+1);

@yersan yersan Jul 24, 2026

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Please always apply the standard code formatting, otherwise in the future applying the format will generate changes

Comment on lines 181 to +182

@yersan yersan Jul 24, 2026

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What hapends if after reading"cliOutputBuffer.toString().contains("\n")" the cliOutputBuffer changes in between before executing the return?

@michpetrov michpetrov Jul 24, 2026

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The method is called after we made sure the buffer shouldn't be changing. But even if it changed it should still be returning the last line of the output, worse case lastIndexOf("\n")+1 is 0.

}else{
return cliOutputBuffer.toString();
}
Expand Down Expand Up @@ -279,18 +280,15 @@ private boolean outputHasPrompt(String prompt){
if (buffer.startsWith("Exception")){
throw new RuntimeException(buffer);
}
if(buffer.contains("\n")) {
if (prompt == null) {
return buffer.substring(buffer.lastIndexOf("\n")+1).matches(".*[\\[].*[\\]].*");
} else {
return buffer.substring(buffer.lastIndexOf("\n")).contains(prompt);
}
}else{
if (prompt == null) {
return buffer.matches(".*[\\[].*[\\]].*");
} else {
return buffer.contains(prompt);
}
if (!idleInput) {
return false;
}

String currentPrompt = getCurrentPrompt();
if (prompt == null) {
return currentPrompt.matches(".*[\\[].*[\\]].*");
} else {
return currentPrompt.contains(prompt);
}
}

Expand All @@ -302,6 +300,8 @@ public CliResultsReader(InputStream inputStream){
cliStream = inputStream;
}

int idleCounter = 0;

@Override
public void run() {
try(java.io.BufferedReader br = new java.io.BufferedReader(new java.io.InputStreamReader(cliStream, StandardCharsets.UTF_8))){
Expand All @@ -310,6 +310,19 @@ public void run() {
// While the next character is a valid character and isn't null
while ((intCharacter = br.read()) != -1 && (character = (char)intCharacter) != null) {
cliOutputBuffer.append(character);
if (character == '\n') {
idleInput = false;
idleCounter = 0;
}

// reader is not ready either after processing CLI output = idle prompt (this happens at most once per line)
// or intermittently while processing user input - this has to be ignored
if (!br.ready()) {
idleInput = idleCounter <= 1;
idleCounter++;
} else {
idleInput = false;
}
Comment on lines +320 to +325

@yersan yersan Jul 24, 2026

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I do not get the behaviour of this logic. Could you explain it here? , why "idleCounter <= 1" and why you do it if the buffer is not ready?

@yersan yersan Jul 24, 2026

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I understand the process will echo the user input, and here what you want to do is to signal when this echo has not finished yet. Also, I understand that the server output is processed as an stream, and I guess this is the main issue.

Correct me if I am wrong, each echo will be following by a new line, and in that moment the output of the command result will start, probably it will contain several lines.

I do not get how this will help with this:

https://github.com/michpetrov/wildfly-core/blob/wfcore-7623-2/testsuite/shared/src/main/java/org/jboss/as/test/integration/management/cli/CliProcessWrapper.java#L232

which seems to be the main issue since outputHasPrompt could be invoked after the input was echoed by the server but the full command output is not fully processed yet.

Would not be easier to use a producer consumer pattern on the threads that reads the std out / err and produce line by line?, consumers will wait until a line is ready, consumers will not read lines in the middle of processing. In general, looks like that sharing the cliOutputBuffer between the CliResultsReader threads and the main thread is quite problematic

@michpetrov michpetrov Jul 24, 2026

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As it is the waitForPrompt method waits until the last line of the buffer contains a certain string. What I want to do is wait until we're sure nothing more will be added to the buffer before checking the strings. Another solution would be to specify the exact string we're expecting but I would have to go through every test.

If we were reading the output line by line we couldn't check the current prompt since that's not a complete line yet. And it would still need some mechanism to tell us the producer is finished producing, wouldn't it?

if reader.ready() returns false that generally means there are no more characters to be read from the stream, unfortunately that's not always the case

If we start with e.g.

[standalone@localhost]

br.read() is blocking, and idleInput is true (because br.ready() was false in the last loop)

We now execute a command, idleInput is set to false as soon as we read a new character.
We print the command, then the output.
Now a prompt starts printing, we get br.ready() == false at the start of the line (counter = 0) but I think this only happens when we color the output, when the prompt is finished we get it again (counter = 1), now the thread is blocking again, idleInput == true and we can check the string.

}
} catch (IOException e) {
fail("Failed to read process output or error streams: " + e.getLocalizedMessage());
Expand Down
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