Resources prototype

[AndrewAXue]

Adds Resource Detection for Google tools like GCE and for environment variable resource detection OTEL_RESOURCE. Follows open-telemetry/oteps#111 (Note at the time of writing this OTEP hasn't been updated after our offline discussion so there's currently some discrepancy).

Example:

import time

from opentelemetry import metrics
from opentelemetry.exporter.cloud_monitoring import (
    CloudMonitoringMetricsExporter,
)
from opentelemetry.sdk.metrics import Counter, MeterProvider
from opentelemetry import trace
from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
from opentelemetry.tools.resource_detector import GoogleCloudResourceDetector
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import SimpleExportSpanProcessor
from opentelemetry.sdk.resources import Resource, get_aggregated_resources

resources = get_aggregated_resources([GoogleCloudResourceDetector()])

metrics.set_meter_provider(MeterProvider(resource=resources))
meter = metrics.get_meter(__name__)
metrics.get_meter_provider().start_pipeline(
    meter, CloudMonitoringMetricsExporter(), 5
)

requests_counter = meter.create_metric(
    name="request_counter",
    description="number of requests",
    unit="1",
    value_type=int,
    metric_type=Counter,
    label_keys=("environment"),
)

staging_labels = {"environment": "staging"}

for i in range(20):
    requests_counter.add(25, staging_labels)
    time.sleep(10)

Tests will be added in the next commit. Doing some manual testing with the code above, it correctly scrapes information when run on a GCE instance and sends it to Monitoring properly.

Addresses issue GoogleCloudPlatform/opentelemetry-operations-python#8

[c24t]

Mostly superficial comments, the direction LGTM.

[c24t]

Changes since the last review LGTM, thanks for updating!

[james-bebbington]

LGTM.

I do think that we should put the GCP resource detection code in a separate package to the trace/metric exporters, as users may want to use the GCP resource detector with a diff BE/exporter, but we can review that later

[aabmass]

Nice! What's the plan for actually registering the detectors the user wants?

[AndrewAXue]

@aabmass for your comment, I plan on adding documentation + examples for both the new propagator and resource detector once we migrate to the new repo. Issue is here GoogleCloudPlatform/opentelemetry-operations-python#13.

[AndrewAXue]

Currently, resource detection is being multi threaded. I'm not too aware of the ramifications of that (stuff like needing to add "suppress_instrumentation" to the context) and would love to get some feedback in that direction :)

[lzchen]

Currently, resource detection is being multi threaded. I'm not too aware of the ramifications of that (stuff like needing to add "suppress_instrumentation" to the context) and would love to get some feedback in that direction :)

I'm not sure what you mean by resource detection is multi threaded. Do you mean detection can happen in parallel (as defined in the otep)?