Transformation of metric data to OTLP data should be a public method

[mayank-yadav2]

Recently, I am designing a framework where we will instrument the data. Then the data has to be converted to OTLP data. Save the data in file. Finally, another service will read the OTLP data from the file and send it to another gateway. So, I want to perform these steps :

• Instrument the data using instrumentation counters.
• As and when the counter is updated, read the data using manual reader. This returns data in sdk.metricdata.ResourceMetrics format.
• Now convert this sdk data into OTLP format data. (This is where there is no public method available to do it. More on this below.)
• Save the OTLP data into a file
• Read this data from the file.

Problem faced :
Now, I see that there is otlpgrpcexporter available that does two things :

1. It transforms the sdk data into OTLP format.
2. It also sends this OTLP data over grpc to the assigned destination.

But I only want to transform the data and not send it. This functionality of only transforming the data into OTLP format is not public. It is inside internal folder, hence making it a private method.

Reasons for it to be a public method :
There are multiple reasons why transforming data into OTLP format should be public :

• The whole point of OTEL is to give you the data in OTLP format. User should have that functionality available where he/she can convert its custom data into OTLP format. (Custom data here being sdk data)
• There is already a public method available to read the data and save it in sdk.metricdata.ResourceMetrics. So, if there is an option to convert your instrumented data into sdk format, why is there no option to convert sdk data into OTLP format. There should also be an option to either collect data in OTLP format or convert sdk data into OTLP format. Since, a lot of users finally want OTLP data from this package.
• This would be helpful for the third-party exporters also. Any developer who is wanting to export data in OTLP format won't have to write its own logic. It should be readily available by this package itself.