I am aware of your point that global don't work in a distributed
environment.
With regard to your other point, these are two different topics with their
own streams. The point of second stream is to set the status to false, so
it can gracefully shutdown the main stream (the one called "md") here
For example, the second stream has this row
+------------------------------------+-------------------+-----+------+
|uuid |timeissued |queue|status|
+------------------------------------+-------------------+-----+------+
|ac74d419-58aa-4879-945d-a2a41bb64873|2023-03-04 21:29:18|md |true |
+------------------------------------+-------------------+-----+------+
so every 30 seconds, it checks the status and if staus = false, it shuts
down the main stream gracefully. It works ok
def sendToControl(dfnewtopic, batchId2):
if(len(dfnewtopic.take(1))) > 0:
print(f"""From sendToControl, newtopic batchId is {batchId2}""")
dfnewtopic.show(100,False)
queue = dfnewtopic.first()[2]
status = dfnewtopic.first()[3]
print(f"""testing queue is {queue}, and status is {status}""")
if((queue == config['MDVariables']['topic']) & (status == 'false')):
spark_session = s.spark_session(config['common']['appName'])
active = spark_session.streams.active
for e in active:
name = e.name
if(name == config['MDVariables']['topic']):
print(f"""\n==> Request terminating streaming process for
topic {name} at {datetime.now()}\n """)
e.stop()
else:
print("DataFrame newtopic is empty")
and so when status set to false in the second it does as below
>From sendToControl, newtopic batchId is 93
+------------------------------------+-------------------+-----+------+
|uuid |timeissued |queue|status|
+------------------------------------+-------------------+-----+------+
|c4736bc7-bee7-4dce-b67a-3b1d674b243a|2023-03-04 21:36:52|md |false |
+------------------------------------+-------------------+-----+------+
*testing queue is md, and status is false*
==> Request terminating streaming process for topic md at 2023-03-04
21:36:55.590162
and shuts down
I want to state this
print(f"""\n==> Request terminating streaming process for topic {name}
and batch {BatchId for md} at {datetime.now()}\n """)
That {BatchId for md} should come from this one
def sendToSink(df, batchId):
if(len(df.take(1))) > 0:
print(f"""From sendToSink, md, batchId is {batchId}, at
{datetime.now()} """)
#df.show(100,False)
df. persist()
# write to BigQuery batch table
#s.writeTableToBQ(df, "append",
config['MDVariables']['targetDataset'],config['MDVariables']['targetTable'])
df.unpersist()
#print(f"""wrote to DB""")
batchidMD = batchId
print(batchidMD)
else:
print("DataFrame md is empty")
I trust I explained it adequately
cheers
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On Sat, 4 Mar 2023 at 21:22, Sean Owen <sro...@gmail.com> wrote:
> I don't quite get it - aren't you applying to the same stream, and
> batches? worst case why not apply these as one function?
> Otherwise, how do you mean to associate one call to another?
> globals don't help here. They aren't global beyond the driver, and, which
> one would be which batch?
>
> On Sat, Mar 4, 2023 at 3:02 PM Mich Talebzadeh <mich.talebza...@gmail.com>
> wrote:
>
>> Thanks. they are different batchIds
>>
>> From sendToControl, newtopic batchId is 76
>> From sendToSink, md, batchId is 563
>>
>> As a matter of interest, why does a global variable not work?
>>
>>
>>
>> view my Linkedin profile
>> <https://www.linkedin.com/in/mich-talebzadeh-ph-d-5205b2/>
>>
>>
>> https://en.everybodywiki.com/Mich_Talebzadeh
>>
>>
>>
>> *Disclaimer:* Use it at your own risk. Any and all responsibility for
>> any loss, damage or destruction of data or any other property which may
>> arise from relying on this email's technical content is explicitly
>> disclaimed. The author will in no case be liable for any monetary damages
>> arising from such loss, damage or destruction.
>>
>>
>>
>>
>> On Sat, 4 Mar 2023 at 20:13, Sean Owen <sro...@gmail.com> wrote:
>>
>>> It's the same batch ID already, no?
>>> Or why not simply put the logic of both in one function? or write one
>>> function that calls both?
>>>
>>> On Sat, Mar 4, 2023 at 2:07 PM Mich Talebzadeh <
>>> mich.talebza...@gmail.com> wrote:
>>>
>>>>
>>>> This is probably pretty straight forward but somehow is does not look
>>>> that way
>>>>
>>>>
>>>>
>>>> On Spark Structured Streaming, "foreachBatch" performs custom write
>>>> logic on each micro-batch through a call function. Example,
>>>>
>>>> foreachBatch(sendToSink) expects 2 parameters, first: micro-batch as
>>>> DataFrame or Dataset and second: unique id for each batch
>>>>
>>>>
>>>>
>>>> In my case I simultaneously read two topics through two separate
>>>> functions
>>>>
>>>>
>>>>
>>>> 1. foreachBatch(sendToSink). \
>>>> 2. foreachBatch(sendToControl). \
>>>>
>>>> This is the code
>>>>
>>>> def sendToSink(df, batchId):
>>>> if(len(df.take(1))) > 0:
>>>> print(f"""From sendToSink, md, batchId is {batchId}, at
>>>> {datetime.now()} """)
>>>> #df.show(100,False)
>>>> df. persist()
>>>> # write to BigQuery batch table
>>>> #s.writeTableToBQ(df, "append",
>>>> config['MDVariables']['targetDataset'],config['MDVariables']['targetTable'])
>>>> df.unpersist()
>>>> #print(f"""wrote to DB""")
>>>> else:
>>>> print("DataFrame md is empty")
>>>>
>>>> def sendToControl(dfnewtopic, batchId2):
>>>> if(len(dfnewtopic.take(1))) > 0:
>>>> print(f"""From sendToControl, newtopic batchId is {batchId2}""")
>>>> dfnewtopic.show(100,False)
>>>> queue = dfnewtopic.first()[2]
>>>> status = dfnewtopic.first()[3]
>>>> print(f"""testing queue is {queue}, and status is {status}""")
>>>> if((queue == config['MDVariables']['topic']) & (status ==
>>>> 'false')):
>>>> spark_session = s.spark_session(config['common']['appName'])
>>>> active = spark_session.streams.active
>>>> for e in active:
>>>> name = e.name
>>>> if(name == config['MDVariables']['topic']):
>>>> print(f"""\n==> Request terminating streaming process
>>>> for topic {name} at {datetime.now()}\n """)
>>>> e.stop()
>>>> else:
>>>> print("DataFrame newtopic is empty")
>>>>
>>>>
>>>> The problem I have is to share batchID from the first function in the
>>>> second function sendToControl(dfnewtopic, batchId2) so I can print it
>>>> out.
>>>>
>>>>
>>>> Defining a global did not work.. So it sounds like I am missing
>>>> something rudimentary here!
>>>>
>>>>
>>>> Thanks
>>>>
>>>>
>>>> view my Linkedin profile
>>>> <https://www.linkedin.com/in/mich-talebzadeh-ph-d-5205b2/>
>>>>
>>>>
>>>> https://en.everybodywiki.com/Mich_Talebzadeh
>>>>
>>>>
>>>>
>>>> *Disclaimer:* Use it at your own risk. Any and all responsibility for
>>>> any loss, damage or destruction of data or any other property which may
>>>> arise from relying on this email's technical content is explicitly
>>>> disclaimed. The author will in no case be liable for any monetary damages
>>>> arising from such loss, damage or destruction.
>>>>
>>>>
>>>>
>>>
