DataFrame representation of all metrics at a given timestamp

[chauhankaranraj]

Currently, the MetricList class can be used to group a metric time series by unique label configs. (See How MetricsList works in MetricList_example.ipynb). This lets the user work with a metric by working with time series values in Metric objects separately.

However in some use cases you might need to work with values of a metric for all different label configs, at a given timestamp.So we need a easy-to-work-with representation for this task.

The basic difference between what's already in the library and what this issue asks for is

1. What exists

metric =

badger_disk_writes:rate1m_Fourier {'ae_source': 'https://prometheus-exporter-alpha-0.thoth-dgraph-stage.svc:8080/debug/prometheus_metrics', 'instance': 'prometheus-aggregate-exporter-thoth-dgraph-stage.cloud.paas.psi.redhat.com:80', 'job': 'Thoth Dgraph aggregate-exporter (stage)', 'monitor': 'datahub', 'value_type': 'yhat_lower'} 

timeseries =

timestamp	value
2020-02-02	0

metric =

badger_disk_writes:rate1m_Fourier {'ae_source': 'https://prometheus-exporter-alpha-0.thoth-dgraph-stage.svc:8080/debug/prometheus_metrics', 'instance': 'prometheus-aggregate-exporter-thoth-dgraph-stage.cloud.paas.psi.redhat.com:80', 'job': 'Thoth Dgraph aggregate-exporter (stage)', 'monitor': 'datahub', 'value_type': 'yhat_upper'} 

timeseries =

timestamp	value
2020-02-02	1

2. What this issue asks for

timestamp = 2020-02-02

name	ae_source	value_type	value	timestamp
badger_disk_writes:rate1m_Fourier	thesource	yhat_lower	0	1583355394
badger_disk_writes:rate1m_Fourier	thesource	yhat_upper	1	1583355394

[4n4nd]

so if I am correct, @chauhankaranraj will implement a new class called MetricSnapshot (maybe some other name) that will instead of looking at the data as a time-series, will look at multiple metric values at an instance. i.e. A snapshot of multiple metrics at a given timestamp.