Is it possible to read information being sent over LogCat in python?
I have a program that is written in java.
Every draw frame it sends tag:"Fps: " message: number
I would like this message to fire an event that I can catch in my python script so I can draw a fps-meter.
Take a look at subprocess. The following code was adapted from Stefaan Lippens
import Queue
import subprocess
import threading
class AsynchronousFileReader(threading.Thread):
'''
Helper class to implement asynchronous reading of a file
in a separate thread. Pushes read lines on a queue to
be consumed in another thread.
'''
def __init__(self, fd, queue):
assert isinstance(queue, Queue.Queue)
assert callable(fd.readline)
threading.Thread.__init__(self)
self._fd = fd
self._queue = queue
def run(self):
'''The body of the tread: read lines and put them on the queue.'''
for line in iter(self._fd.readline, ''):
self._queue.put(line)
def eof(self):
'''Check whether there is no more content to expect.'''
return not self.is_alive() and self._queue.empty()
# You'll need to add any command line arguments here.
process = subprocess.Popen(["logcat"], stdout=subprocess.PIPE)
# Launch the asynchronous readers of the process' stdout.
stdout_queue = Queue.Queue()
stdout_reader = AsynchronousFileReader(process.stdout, stdout_queue)
stdout_reader.start()
# Check the queues if we received some output (until there is nothing more to get).
while not stdout_reader.eof():
while not stdout_queue.empty():
line = stdout_queue.get()
if is_fps_line(line):
update_fps(line)
Of course, you'll need to write the is_fps_line and update_fps functions yourself.
I would redirect adb logcat to your python script. This would look like:
$ adb logcat | python yourscript.py
Now you can read from logcat on sys.stdin and parse it however you like.
Related
I want to pull a file from my android device through an adb command from my macOS application.
Everything works perfect with the code below, except when the name of the file I want to pull contains special characters like german umlauts (äöüÄÖÜ).
I get this error:
adb: error: failed to stat remote object '/storage/emulated/0/Download/Böse': No such file or directory.
But when I use the command adb pull /storage/emulated/0/Download/Böse ~/Desktop from within the Terminal.app, the file will be pulled to my computer.
The strange thing here is that if I copy the substring /storage/emulated/0/Download/Böse from the Xcode console output, the command is also not working within the Terminal.app until I delete the ö and replace it with an ö from my keyboard input.
I tried replacing the ö with the unicode representation \u{00f6}, but this has no effect (but the console output still shows an ö but the 'wrong' encoded one.
// Configure task.
let task = Process()
task.launchPath = "~/Library/Android/sdk/platform-tools/adb"
task.arguments = ["pull", "/storage/emulated/0/Download/Böse", "~/Desktop"]
// Configure pipe.
let pipe = Pipe()
task.standardOutput = pipe
task.standardError = pipe
task.launch()
// Run task.
let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output = String(data: data, encoding: .utf8)
task.waitUntilExit()
// adb: error: failed to stat remote object '/storage/emulated/0/Download/Böse': No such file or directory
print(output)
I found the following in the documentation, how the Process handles the arguments that I provide:
The NSTask object converts both path and the strings in arguments to appropriate C-style strings (using fileSystemRepresentation) before passing them to the task via argv[] . The strings in arguments do not undergo shell expansion, so you do not need to do special quoting, and shell variables, such as $PWD, are not resolved.
It seems like I am not the only one with this problem, and I found this workaround:
How to work around NSTask calling -[NSString fileSystemRepresentation] for arguments, but I was not able to make it work with Swift.
As a workaround I am now writing my adb command to a file and execute it from a bash command in my application.
let source = "/storage/emulated/0/Download/Böse"
let destination = "~/Desktop"
guard let uniqueURL = URL(string: destination + "/" + ProcessInfo.processInfo.globallyUniqueString) else { return }
// Write command to file
let scriptContent = "#!/bin/bash\n~/Library/Android/sdk/platform-tools/adb pull -a \"" + source + "\" \"" + destination + "\""
try? scriptContent.write(to: uniqueURL, atomically: false, encoding: .utf8)
// Configure task.
let task = Process()
task.environment = ["LC_ALL": "de_DE.UTF-8", "LANG": "de_DE.UTF-8"]
task.launchPath = "/bin/bash"
task.arguments = [uniqueURL.path]
// Configure pipe.
let pipe = Pipe()
task.standardOutput = pipe
task.standardError = pipe
try? task.run()
// Run task.
let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output = String(data: data, encoding: .utf8)
task.waitUntilExit()
print(output)
Even though this is working for now, it is not a satisfactory solution as it is not very elegant and not efficient too, so any improvements or better answers are welcome.
PROBLEM:
Every time I run this python function in my monkeyrunner.py script, it opens a new background instance of (cmd, adb, and conhost). And so, in my automation script, if I have a loop that uses that 100 times, I'm going to see 100 of each cmd, adb, and conhost running in the background (I know this because I enter "ps" in powershell to get the list of processes.) The purpose of the function, if you're curious, is to look for logcat messages from the USB attached Android tablet, to see when processes are finished, so that the script knows when to command screen touches to move forward with automation testing.
action = "____"
waitTime = 1
def adb(logMessage, action):
start = time.time()
p = subprocess.Popen("adb logcat -v time", shell=True, cwd="C:\Users\<USERNAME>\AppData\Local\Android\sdk\platform-tools", stdout=subprocess.PIPE)
for line in p.stdout:
if logMessage in line:
print("Found message!")
break
pass
else:
continue
QUESTION:
How can I use "subprocess" to open adb WITHOUT opening a new instance each time? Is there a way to close the subprocess in the same function?
2 things.
adb logcat is a blocking call. It doesn't return unless you send it a SIGINT (ctrl +c). So inside a script you have to send it the "-d" flag. If you forget your script will keep waiting.
you can wait for a subprocess to complete with p.wait()
Therefore you can try this
action = "____"
waitTime = 1
def adb(logMessage, action):
start = time.time()
p = subprocess.Popen("adb logcat -d -v time", shell=True, cwd="C:\Users\<USERNAME>\AppData\Local\Android\sdk\platform-tools", stdout=subprocess.PIPE)
#p.wait()
for line in p.stdout:
if logMessage in line:
print("Found message!")
break
pass
else:
continue
This will ensure that every adb session launched to look at logact terminates properly and its output is looked at only after it returns
EDIT: You are absolutely right, p.wait() isn't needed and is actually wrong! because the logcat writes more than 4kb to stdout in yourcase. You could try to use commuinicate instead to help with that
I figured it out. To prevent a new session of adb from opening in the background per each time this function is called, all I had to do is place the "p" variable outside the function.... like this...
p = subprocess.Popen("adb logcat -v time", shell=True, cwd="C:\Users\<USERNAME>\AppData\Local\Android\sdk\platform-tools", stdout=subprocess.PIPE)
action = "____"
waitTime = 1
def adb(logMessage, action):
start = time.time()
for line in p.stdout:
if logMessage in line:
print("Found message!")
break
pass
else:
continue
There is still the issue of a single adb session that opens and does not close after the script is run. So, now, instead of 180 sessions (or more) opening, there is a single one. If I find out how to close the session I will update this ticket.
I want to create an AVD (Android Virtual Device) through command line in python. For that, I need to pass a string n to the stdin. I have tried the following
emulator_create = str(subprocess.check_output([android,'create', 'avd', '-n', emulator_name, '-t', target_id, '-b', abi],stdin=PIPE))
emulator_create.communicate("n")
but it raises the following error
raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['/home/fahim/Android/Sdk/tools/android', 'create', 'avd', '-n', 'samsung_1', '-t', '5', '-b', 'android-tv/x86']' returned non-zero exit status 1
Process finished with exit code 1
What can I do?
There's something not working with your example. subprocess.check_output() returns the output from the child process you want to execute, not a handle to this process. In other words you get a string object (or maybe a bytes object) which you cannot use to manipulate the child process.
Probably what happens is that your script, using subprocess.check_output(), will execute the child process and wait until it is finished before continuing. But since you are never able to communicate with it, it will finish with a non-zero return value which will raise the subprocess.CalledProcessError
Now, using grep as an example of a command that waits on the standard input to execute something (since I don't have an Android Virtual Device creator installed) you could do this:
#!/usr/bin/env python2.7
import subprocess
external_command = ['/bin/grep', 'StackOverflow']
input_to_send = '''Almost every body uses Facebook
You can also say that about Google
But you can find an answer on StackOverflow
Even if you're an old programmer
'''
child_process = subprocess.Popen(args=external_command,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
universal_newlines=True)
stdout_from_child, stderr_from_child = child_process.communicate(input_to_send)
print "Output from child process:", stdout_from_child
child_process.wait()
It will print "Output from child process: But you can find an answer on StackOverflow", which is the output from grep.
In this example, I have
Used the class subprocess.Popen to create an handle to the child process
Setting arguments stdin and stdout with the value subprocess.PIPE to enables us to communicate later on with this process.
Used its .communicate() method to send a string to its standard input. In the same step, I retrieved its standard output and standard error output.
Printed the standard output retrieved in the last step (just so to show that it is actually working)
Waited that this child process is finished
In Python 3.5, it's even simpler:
#!/usr/bin/env python3.5
import subprocess
external_command = ['/bin/grep', 'StackOverflow']
input_to_send = '''Almost every body uses Facebook
You can also say that about Google
But you can find an answer on StackOverflow
Even if you're an old programmer
'''
completed_process_result = subprocess.run(args=external_command,
input=input_to_send,
stdout=subprocess.PIPE,
universal_newlines=True)
print("Output from child process:", completed_process_result.stdout)
In this example, I have:
Used the module function subprocess.run() to execute the command.
The input argument is the string we send to the standard input of the child process
The return value is used later on to retreive the output of the child process
Now you have to adapt this code to your situation.
I am trying to run some GMock/GTest tests on Android. These all run fine, but there's no output, as GMock logs to stdout.
I've tried the following with no luck (likely because it's for the Dalvik VM, and they've done away with that in Android 5):
$ adb shell stop
$ adb shell setprop log.redirect-stdio true
$ adb shell start
When log.redirect-stdio is set to true, there is still no output from stdio to logcat.
I've also tried custom several streambuf implementations with std::cout.rdbuf to try to direct stdout to logcat with __android_log_print, but none of these have printed anything to logcat.
Has anyone successfully managed to redirect stdout to logcat in Android 5?
I can add more details (such as streambuf implementations I've tried) if needed.
This isn't really a solution to the problem of redirecting stdout to logcat, but I'm suggesting it as a workaround in case it helps someone.
You can redirect stdout to a file instead:
freopen("/data/data/com.your.package/files/out.txt", "w", stdout);
... // Call GMock which prints to the file instead
fclose(stdout)
We can then cat the file to see the logged test results. Sadly Android doesn't have tail so the logging isn't nicely available in real time. (Unless you're good at spamming cat)
Do it with the old Java way: (but I am using kotlin, can anyone suggest a cleaner version?)
documentation: System.setOut()
import java.io.OutputStream
import java.io.PrintStream
private const val TAG = "MyActivity"
class LogcatOutputStream: OutputStream(){
private var line_buffer: StringBuilder = StringBuilder()
override fun write(b: Int){
when(b){
'\n'.toInt() -> {
Log.i(TAG, line_buffer.toString())
line_buffer.setLength(0)
}
else -> line_buffer.append(b.toChar())
}
}
}
// put this somewhere in the code, like onCreate() as shown
class MainActivity: Activity(){
override fun onCreate(savedInstanceState: Bundle?){
// some other code
PrintStream(LoggerOutputStream()).let{
System.setOut(it)
System.setErr(it)
}
// some other code
}
}
// result:
println("Hello World") // which is effectively System.out.println in Java
// with have the below output in logcat
I/MyActivity(<pid>): Hello World
// as a reminder, you can filter logcat by tags
adb logcat MyActivity:D
// to only show logs tagged with 'MyActivity' (same value as 'TAG' above)
Making an app at the moment for my personal use (rooted) and it requires getting certain pixels colors from the screen. I was trying to accomplish this through the Runtime.
Process p = Runtime.getRuntime().exec("screencap");
p.waitFor();
InputStream is = p.getInputStream()
BitmapFactory.decodeStream(is);
and I get factory returned null.
but if I dump the process to my sd card through adb -d shell screencap /sdcard/ss.dump and access it from my app
BitmapFactory.decodeFile("/sdcard/ss.dump");
all goes well.
So it there anyway to dump the stream straight into BitmapFactory within my app?
Thanks SO and please excuse the generally laziness/shortcuts of the example code.
This might help if not too far off your intended path. (I think you are using node / javascript). I spawned the ADB.EXE command producing a stream (and being 'jailed' on Windows the program must transform the stream to account for linefeed ending differences. So with that, I have working the following:
exports.capture = function(filename) {
// you'll need to map your requirement (decodeStream) instead
// of streaming to a file
var strm = fs.createWriteStream(path);
var cv = new Convert();
cv.pipe(strm);
var capture = spawn(cmd, args);
capture.stdout.on('data', function(data) {
cv.write(data);
});
capture.stdout.on('exit', function(data) {
cv.end();
});
}
To explain the process, spawn is running the ADB command, on windows, CR-LF are inserted (being a PNG stream), and stream is chunked / piped through a fs-transformation. Others on the web have described the process as adb.exe shell screencap -p | sed 's/\r$//' > output.file. And it does work. To be clear the conversion is CR-CR-LF => LF for us window jailed birds. And if you don't want to implement a SED and not use javascript regular expressions converting binary->strings->binary, you may follow my path. There is probably a simpler way, I just don't know what it is...
So, Convert() is an object with methods that converts the byte stream on the fly.
See the codewind blog link is: http://codewinds.com/blog/2013-08-20-nodejs-transform-streams.html to build your convert.
When using screencap from inside an app you must use su, i.e. root. When you do this via adb it runs under a different user id, which has more permissions than a normal Android app.
There are several examples how to use screencap, e.g. here.