How to check task status in Celery

Question

How does one check whether a task is running in celery  specifically  I m using celery-django    I ve read the documentation  and I ve googled  but I can t see a call like   my example task state      RUNNING   My use-case is that I have an external  java  service for transcoding  When I send a document to be transcoded  I want to check if the task that runs that service is running  and if not  to  re start it   I m using the current stable versions - 2 4  I believe

User · Answer

First in your celery APP    vi my celery apps app1 py  app   Celery worker name     and next  change to the task file import app from your celery app module    vi tasks task1 py  from my celery apps app1 import app  app AsyncResult taskid   try     if task state lower       success           return except          do something

User · Answer

res   method delay        print f quot id  res id   state  res state   status  res status   quot    print res get

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Answer of 2020        tasks py  celery task   def mytask arg1       print arg1        blueprint py  bp route   args arg1  lt arg1 gt    def sleeper arg1       process   mytask apply async args  arg1     mytask delay arg1      state   process state     return f Thanks for your patience  your job  process task id                 is being processed  Status  state

User · Answer

Just use this API from celery FAQ  result   app AsyncResult task id    This works fine

User · Answer

Return the task id  which is given from  delay    and ask the celery instance afterwards about the state   x   method delay 1 2  print x task id   When asking  get a new AsyncResult using this task id   from celery result import AsyncResult res   AsyncResult  your-task-id   res ready

User · Answer

Try   task AsyncResult task request id  state   this will provide the Celery Task status  If Celery Task is already is under FAILURE state it will throw an Exception    raised unexpected  KeyError  exc type

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You can also create custom states and update it s value duting task execution  This example is from docs    app task bind True  def upload files self  filenames       for i  file in enumerate filenames           if not self request called directly              self update state state  PROGRESS                   meta   current   i   total   len filenames      http   celery readthedocs org en latest userguide tasks html custom-states

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Apart from above Programmatic approach Using Flower Task status can be easily seen   Real-time monitoring using Celery Events  Flower is a web based tool for monitoring and administrating Celery clusters    Task progress and history Ability to show task details  arguments  start time  runtime  and more   Graphs and statistics   Official Document   Flower - Celery monitoring tool  Installation     pip install flower   Usage   http   localhost 5555

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Every Task object has a  request property  which contains it AsyncRequest object  Accordingly  the following line gives the state of a Task task   task AsyncResult task request id  state

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Creating an AsyncResult object from the task id is the way recommended in the FAQ to obtain the task status when the only thing you have is the task id   However  as of Celery 3 x  there are significant caveats that could bite people if they do not pay attention to them  It really depends on the specific use-case scenario   By default  Celery does not record a  running  state   In order for Celery to record that a task is running  you must set task track started to True  Here is a simple task that tests this    app task bind True  def test self       print self AsyncResult self request id  state   When task track started is False  which is the default  the state show is PENDING even though the task has started  If you set task track started to True  then the state will be STARTED   The state PENDING means  I don t know    An AsyncResult with the state PENDING does not mean anything more than that Celery does not know the status of the task  This could be because of any number of reasons   For one thing  AsyncResult can be constructed with invalid task ids  Such  tasks  will be deemed pending by Celery    gt  gt  gt  task AsyncResult  invalid   status  PENDING    Ok  so nobody is going to feed obviously invalid ids to AsyncResult  Fair enough  but it also has for effect that AsyncResult will also consider a task that has successfully run but that Celery has forgotten as being PENDING  Again  in some use-case scenarios this can be a problem  Part of the issue hinges on how Celery is configured to keep the results of tasks  because it depends on the availability of the  tombstones  in the results backend    Tombstones  is the term use in the Celery documentation for the data chunks that record how the task ended   Using AsyncResult won t work at all if task ignore result is True  A more vexing problem is that Celery expires the tombstones by default  The result expires setting by default is set to 24 hours  So if you launch a task  and record the id in long-term storage  and more 24 hours later  you create an AsyncResult with it  the status will be PENDING    All  real tasks  start in the PENDING state  So getting PENDING on a task could mean that the task was requested but never progressed further than this  for whatever reason   Or it could mean the task ran but Celery forgot its state   Ouch  AsyncResult won t work for me  What else can I do   I prefer to keep track of goals than keep track of the tasks themselves  I do keep some task information but it is really secondary to keeping track of the goals  The goals are stored in storage independent from Celery  When a request needs to perform a computation depends on some goal having been achieved  it checks whether the goal has already been achieved  if yes  then it uses this cached goal  otherwise it starts the task that will effect the goal  and sends to the client that made the HTTP request a response that indicates it should wait for a result     The variable names and hyperlinks above are for Celery 4 x  In 3 x the corresponding variables and hyperlinks are  CELERY TRACK STARTED  CELERY IGNORE RESULT  CELERY TASK RESULT EXPIRES

User · Answer

Old question but I recently ran into this problem    If you re trying to get the task id you can do it like this    import celery from celery app import add from celery import uuid  task id   uuid   result   add apply async  2  2   task id task id    Now you know exactly what the task id is and can now use it to get the AsyncResult     grab the AsyncResult  result   celery result AsyncResult task id     print the task id print result task id 09dad9cf-c9fa-4aee-933f-ff54dae39bdf    print the AsyncResult s status print result status SUCCESS    print the result returned  print result result 4

User · Answer

I found helpful information in the  Celery Project Workers Guide inspecting-workers  For my case  I am checking to see if Celery is running    inspect workers   task app control inspect   if inspect workers registered   is None      state    FAILURE  else      state   str task state     You can play with inspect to get your needs

User · Answer

for simple tasks  we can use http   flower readthedocs io en latest screenshots html and http   policystat github io jobtastic  to do the monitoring    and for complicated tasks  say a task which deals with a lot other modules  We recommend manually record the progress and message on the specific task unit

[python] How to check task status in Celery?

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