I'm using Twitter's logging framework in Scala, version 6.5.0.
I've written a toy usage example:
import com.twitter.logging._
object TestFormatter extends Formatter
{
override def format( record : java.util.logging.LogRecord) = "TEST %s> ".format( record.getLevel.getName ) + formatText(record) + lineTerminator
}
object Main extends App
{
override def main( args : Array[String] ) : Unit =
{
// obtain a logger
val log = Logger.get( getClass )
// clear any existing message handlers
Logger.clearHandlers
// add a new handler, using my toy formatter
log.addHandler( ConsoleHandler( TestFormatter, Some( Level.DEBUG ) )() )
// log a couple of test messages
log.debug( "DEBUG LOG" )
log.warning( "WARNING LOG" )
}
}
The class TestFormatter isn't really necessary, but will help to highlight my problem. I'm pretty sure that what I should see from this by way of output from this code is something along the lines of:
TEST DEBUG> DEBUG LOG
TEST WARNING> WARNING LOG
However, what I actually get is:
TEST WARNING> WARNING LOG
WARNING: WARNING LOG
This raises two issues:
Why has some other handler also handled my warning message, despite me clearing existing handlers? - SOLVED
Why, when I've set the level of my logger to debug, has the message I logged at debug level not been handled?
If anyone could throw any light on either of these problems, I'd be most grateful.
For the first question, you can change your code to use Logger.clearHandlers to get rid of the additional handler.
Second question: you could add log.setLevel(Level.DEBUG) to get the output you are expecting. As for what setting the level of the handler does, it doesn't seem to control anything. So it is bug; at the very least a documentation bug in their library.
As it turns out, I wasn't using the framework in the expected manner. I've found that the LoggerFactory class is the way that you're supposed to make changes to your loggers. My main method should have been as follows:
override def main( args : Array[String] ) : Unit =
{
val log = Logger.get( "" )
LoggerFactory(
node = "",
level = Some( Level.DEBUG ),
handlers = List( ConsoleHandler( TestFormatter, Some( Level.DEBUG ) ) )
).apply()
log.debug( "DEBUG LOG" )
log.warning( "WARNING LOG" )
}
I'm still not entirely sure why the original code doesn't work, especially since the source of LoggerFactory seems to suggest that it registers the new Handlers by calling addHandler().
However, the output of this main method is:
TEST DEBUG> DEBUG LOG
TEST WARNING> WARNING LOG
which is what I was looking for.
Related
From the documentation I can see that I should be able to use WriteResult.ok, WriteResult.code and WriteResult.n in order to understand errors and the number of updated documents but this isn't working. Here is a sample of what I'm doing (using reactiveMongoDB/Play JSON Collection Plugin):
def updateOne(collName: String, id: BSONObjectID, q: Option[String] = None) = Action.async(parse.json) { implicit request: Request[JsValue] =>
val doc = request.body.as[JsObject]
val idQueryJso = Json.obj("_id" -> id)
val query = q match {
case Some(_) => idQueryJso.deepMerge(Json.parse(q.get).as[JsObject])
case None => idQueryJso
}
mongoRepo.update(collName)(query, doc, manyBool = false).map(result => writeResultStatus(result))
}
def writeResultStatus(writeResult: WriteResult): Result = {
// NOT WORKING
if(writeResult.ok) {
if(writeResult.n > 0) Accepted else NotModified
} else BadRequest
}
Can I give an alternative approach here? You said:
"in order to understand errors and the number of updated documents but this isn't working"
Why you don't use the logging functionality that Play provides? The general idea is that:
You set the logging level (e.g., only warning and errors, or errors, etc.).
You could use the log to output a message in any case, either something is ok, or it is not.
Play saves the logs of your application while it is running.
You the maintainer/developer could look into the logs to check if there is any errors.
This approach open a great possibility in the future: you could save the logs into a third-party service and put monitoring functionalities on the top of it.
Now if we look at the documentation here, you see about different log levels, and how to use the logger.
I'm writing Selenium tests with ScalaTest's Selenium DSL and I'm running into timeouts I can't explain. To make matters more complicated, they only seem to happen some of the time.
The problem occurs whenever I access an Element after a page load or some Javascript rendering. It looks like this:
click on "editEmployee"
eventually {
textField(name("firstName")).value = "Steve"
}
My PatienceConfig is configured like this:
override implicit val patienceConfig: PatienceConfig =
PatienceConfig(timeout = Span(5, Seconds), interval = Span(50, Millis))
The test fails with the following error:
- should not display the old data after an employee was edited *** FAILED ***
The code passed to eventually never returned normally. Attempted 1 times over 10.023253653000001 seconds.
Last failure message: WebElement 'firstName' not found.. (EditOwnerTest.scala:24)
It makes sense that it doesn't succeed immediately, because the click causes some rendering, and the textfield may not be available right away. However, it shouldn't take 10 seconds to make an attempt to find it, right?
Also, I find it very interesting that the eventually block tried it only once, and that it took almost precisely 10 seconds. This smells like a timeout occurred somewhere, and it's not my PatienceConfig, because that was set to time out after 5 seconds.
With this workaround, it does work:
click on "editEmployee"
eventually {
find(name("firstName")).value // from ScalaTest's `OptionValues`
}
textField(name("firstName")).value = "Steve"
I did some digging in the ScalaTest source, and I've noticed that all calls that have this problem (it's not just textField), eventually call webElement at some point. The reason why the workaround works, is because it doesn't call webElement. webElement is defined like this:
def webElement(implicit driver: WebDriver, pos: source.Position = implicitly[source.Position]): WebElement = {
try {
driver.findElement(by)
}
catch {
case e: org.openqa.selenium.NoSuchElementException =>
// the following is avoid the suite instance to be bound/dragged into the messageFun, which can cause serialization problem.
val queryStringValue = queryString
throw new TestFailedException(
(_: StackDepthException) => Some("WebElement '" + queryStringValue + "' not found."),
Some(e),
pos
)
}
}
I've copied that code into my project and played around with it, and it looks like constructing and/or throwing the exception is where most of the 10 seconds are spent.
(EDIT Clarification: I've actually seen the code actually spend its 10 seconds inside the catch block. The implicit wait is set to 0, and besides, if I remove the catch block everything simply works as expected.)
So my question is, what can I do to avoid this strange behaviour? I don't want to have to insert superfluous calls to find all the time, because it's easily forgotten, especially since, as I said, the error occurs only some of the time. (I haven't been able to determine when the behaviour occurs and when it doesn't.)
It is clear that the textField(name("firstName")).value = "Steve" ends up calling the WebElement as you have found out.
Since the issue in the op is happening where ever web elements are involved (which in turn implies that webdriver is involved), I think it is safe to assume that the issue is related to the implicit wait on the Web driver.
implicitlyWait(Span(0, Seconds))
The above should ideally fix the issue. Also, making implicit wait to be 0 is a bad practice. Any web page might have some loading issues. The page load is handled by Selenium outside its wait conditions. But slow element load (may be due to ajax calls) could result in failure. I usually keep 10 seconds as my standard implicit wait. For scenarios which require more wait, explicit waits can be used.
def implicitlyWait(timeout: Span)(implicit driver: WebDriver): Unit = {
driver.manage.timeouts.implicitlyWait(timeout.totalNanos, TimeUnit.NANOSECONDS)
}
Execution Flow:
name("firstName") ends up having value as Query {Val by = By.className("firstName") }.
def name(elementName: String): NameQuery = new NameQuery(elementName)
case class NameQuery(queryString: String) extends Query { val by = By.name(queryString) }
Query is fed to the textField method which calls the Query.webElement as below.
def textField(query: Query)(implicit driver: WebDriver, pos: source.Position): TextField = new TextField(query.webElement)(pos)
sealed trait Query extends Product with Serializable {
val by: By
val queryString: String
def webElement(implicit driver: WebDriver, pos: source.Position = implicitly[source.Position]): WebElement = {
try {
driver.findElement(by)
}
catch {
case e: org.openqa.selenium.NoSuchElementException =>
// the following is avoid the suite instance to be bound/dragged into the messageFun, which can cause serialization problem.
val queryStringValue = queryString
throw new TestFailedException(
(_: StackDepthException) => Some("WebElement '" + queryStringValue + "' not found."),
Some(e),
pos
)
}
}
}
I don't know ScalaTest's specifics, but such strange timeouts usually occur when you're mixing up implicit and explicit waits together.
driver.findElement uses implicit waits internally. And depending on specified explicit waits timeout, you may face with summing both together.
Ideally, implicit waits should be set to 0 to avoid such issues.
If I started a process using Scala Process/ProcessBuilder. How can I get the pid of the process that was created?
I could not find any mention of the pid in the official docs:
http://www.scala-lang.org/api/2.10.4/index.html#scala.sys.process.Process
http://www.scala-lang.org/api/2.10.4/index.html#scala.sys.process.ProcessBuilder
http://www.scala-lang.org/api/2.10.4/index.html#scala.sys.process.package
2016: same question; I've been clicking through related questions for a few minutes, but still couldn't find any solution that is generally agreed upon. Here is a Scala version inspired by LRBH10's Java code in the answer linked by wingedsubmariner:
import scala.sys.process.Process
def pid(p: Process): Long = {
val procField = p.getClass.getDeclaredField("p")
procField.synchronized {
procField.setAccessible(true)
val proc = procField.get(p)
try {
proc match {
case unixProc
if unixProc.getClass.getName == "java.lang.UNIXProcess" => {
val pidField = unixProc.getClass.getDeclaredField("pid")
pidField.synchronized {
pidField.setAccessible(true)
try {
pidField.getLong(unixProc)
} finally {
pidField.setAccessible(false)
}
}
}
// If someone wants to add support for Windows processes,
// this would be the right place to do it:
case _ => throw new RuntimeException(
"Cannot get PID of a " + proc.getClass.getName)
}
} finally {
procField.setAccessible(false)
}
}
}
// little demo
val proc = Process("echo 'blah blah blaaah'").run()
println(pid(proc))
WARNING: scala code runner is essentially just a bash script, so when you use it to launch scala programs, it will do thousand things before actually starting the java process. Therefore, the PID of the java-process that you are actually interested in will be much larger than what the above code snippet returns. So this method is essentially useless if you start your processes with scala. Use java directly, and explicitly add Scala library to the classpath.
The scala.sys.io.process classes are wrappers around the Java classes for starting processes, and unfortunately it is difficult to obtain the PID from this API. See the stackoverlow question for this, How to get PID of process I've just started within java program?.
I have a small Play (2.1.2) application that tries to store some data and perform a redirect. I have 2 specs:
"save the user" in {
running(FakeApplication()) {
val Some(create) = route(
FakeRequest(PUT, "/users")
.withSession(("user-id", user_id))
.withFormUrlEncodedBody(("username", any_username))
)
status(create) must equalTo(SEE_OTHER)
redirectLocation(create).map(_ must equalTo("/profile")) getOrElse failure("missing redirect location")
}
}
"display errors with missing username" in {
running(FakeApplication()) {
val Some(create) = route(
FakeRequest(PUT, "/users")
.withSession(("user-id", user_id))
)
status(create) must equalTo(BAD_REQUEST)
contentAsString(create) must contain ("This field is required")
}
}
When I run these tests, the second test has the same result as the first one, so a SEE_OTHER instead of the BAD_REQUEST. When I change the order of the tests, both work fine. The second one also passes when I delete the first one.
Does Scala / Play / Specs2 somehow remember state across tests or requests? Is there anything I need to do to ensure they run in isolation?
EDIT:
The code in my controller looks like this:
val form: Form[User] = Form(
mapping(
"username" -> nonEmptyText
)(user => User(username))(user=> Some(user.username))
)
form.bindFromRequest.fold(
errors => BadRequest(views.html.signup(errors)),
user => Redirect("/profile")
)
Playframework 2/Specs2 does not keep state between tests unless you keep state in your test classes, your application or any external place you keep data.
If for example your application would save a user to a database in one test and test for the existance of that user in another test then of course that would make your test interfere with each other.
So I guess you need to figure out some way to clean out the database where you keep your data between each test.
i'm trying to get a clean and gracefull shutdown, and for some reason, it wont execute. iv'e tried:
sys addShutdownHook{
logger.warn("SHUTTING DOWN...")
// irrelevant logic here...
}
and also:
Runtime.getRuntime.addShutdownHook(ThreadOperations.delayOnThread{
logger.warn("SHUTTING DOWN...")
// irrelevant logic here...
}
)
where ThreadOperations.delayOnThread definition is:
object ThreadOperations {
def startOnThread(body: =>Unit) : Thread = {
onThread(true, body)
}
def delayOnThread(body: =>Unit) : Thread = {
onThread(false, body)
}
private def onThread(runNow : Boolean, body: =>Unit) : Thread = {
val t=new Thread {
override def run=body
}
if(runNow){t.start}
t
}
// more irrelevant operations...
}
but when i run my program (executable jar, double activation), the hook does not start. so what am i doing wrong? what is the right way to add a shutdown hook in scala? is it in any way related to the fact i'm using double activation?
double activation is done like that:
object Gate extends App {
val givenArgs = if(args.isEmpty){
Array("run")
}else{
args
}
val jar = Main.getClass.getProtectionDomain().getCodeSource().getLocation().getFile;
val dir = jar.dropRight(jar.split(System.getProperty("file.separator")).last.length + 1)
val arguments = Seq("java", "-cp", jar, "boot.Main") ++ givenArgs.toSeq
Process(arguments, new java.io.File(dir)).run();
}
(scala version: 2.9.2 )
thanks.
In your second attempt, your shutdown hook you seems to just create a thread and never start it (so it just gets garbage collected and does nothing). Did I miss something? (EDIT: yes I did, see comment. My bad).
In the first attempt, the problem might just be that the underlying log has some caching, and the application exits before the log is flushed.
Solved it.
For some reason, I thought that run as opposed to ! would detach the process. It actually hangs on because there are open streams left to the Process, which is returned from run (or maybe it just hangs for another reason, 'cause exec doesn't hang, but returns a Process with open streams to and from the child process, much like run). For this reason, the original process was still alive, and I accidentally sent the signals to it. Of course, it did not contain a handler, or a shutdown hook, so nothing happened.
The solution was to use Runtime.getRuntime.exec(arguments.toArray) instead of Process(arguments, new java.io.File(dir)).run();, close the streams in the Gate object, and send the ^C signal to the right process.