Storing values that is not present in the message

Store
1

I have a MQTT stream where I only want to keep the unixtimestamp, the rest of the data is not important and doesn’t contain the data I want to store.
The message is sent every time I have consumed 100l of water and unfortunately doesn’t contain the number 100.
Is there a way where i can use the timestamp from the message and then insert 100 into the database?

2

You could use count() to see how many messages you get (no matter what the
content is) in a given time period, then multiply that by 100 in your query,
and get the number of litres of water.

Antony.

3

Tried that but cant figure out how to get it cumulative!
Thought it would be most flexible for the future to get the real value in the database!

4

Hi @pettaflex , welcome !

that is possible …

> insert mqstream message="limit reached"
> insert mqstream message="limit reached"
> insert mqstream message="limit reached"
> select * from mqstream
name: mqstream
time                message
----                -------
1556883246767552172 limit reached
1556883254824113777 limit reached
1556883259568610336 limit reached
>
> insert mqstream value=100 1556883254824113777
>
> select * from mqstream
name: mqstream
time                message       value
----                -------       -----
1556883246767552172 limit reached
1556883254824113777 limit reached 100
1556883259568610336 limit reached
>

best regards

5

Is that possible with Telegraf?
I’m getting the stream trough MQTT and Telegraf!

6

Hi , yes , I guess :slight_smile:

from this document : telegraf/CONFIGURATION.md at master · influxdata/telegraf · GitHub

you can add tags to inputs , this is an example based on the above document for cpu …
I guess you can do the same for MQTT

$ cat cpu.conf
[agent]
  omit_hostname = false
  hostname = "influxserver.com"

[[inputs.cpu]]
   fieldpass = ["usage_idle"]
 [inputs.cpu.tags]
   this_is_my_added_tag="100"


$ telegraf --config  cpu.conf --test
2019-05-03T12:36:06Z I! Starting Telegraf 1.10.1
> cpu,cpu=cpu0,host=influxserver.com,this_is_my_added_tag=100 usage_idle=100 1556886967000000000
> cpu,cpu=cpu1,host=influxserver.com,this_is_my_added_tag=100 usage_idle=100 1556886967000000000
> cpu,cpu=cpu-total,host=influxserver.com,this_is_my_added_tag=100 usage_idle=99.00990098918604 1556886967000000000

I have tried that with inputs.cpu.fields but that didn’t work

7

Hi.

Seems that tags only marks the data, it’s not possible to use the tag in calculations!

/Peter

8

Hi ,

to use the tag in calculations ,
I convert it to an integer using the processor.converter in telegraf.

[[processors.converter]]
  [processors.converter.tags]
    integer = ["this_is_my_added_tag"]

the converter creates an extra field which you can access by adding ::field …

> select this_is_my_added_tag::field,this_is_my_added_tag::field *7 from cpu order by desc limit 5
name: cpu
time                this_is_my_added_tag this_is_my_added_tag_1
----                -------------------- ----------------------
1557145110000000000 100                  700
1557145110000000000 100                  700
1557145110000000000 100                  700
1557145100000000000 100                  700
1557145100000000000 100                  700

I also tested what happens when I drop the measurement cpu ,
then the tag is gone and only the field with the value 100 remains …

So to add a default field in a measurement , you can combine the
[inputs.cpu.tags] //in my case
and the
[processors.converter.tags]
integer = [“this_is_my_added_tag”]

here is a link to the converter
and there is also the rename that you could use …

hope this solves your problem ,
best regards