Merge pull request #9 from NipunaMadhushan/main

Include Module.md

ballerina/Module.md

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+## Package Overview
+
+The New Relic Observability Extension is one of the observability extensions in the <a target="_blank" href="https://ballerina.io/">Ballerina</a> language.
+
+It provides an implementation for tracing and metrics and, publishing both metrics and traces to a <a target="_blank" href="https://newrelic.com/">New Relic</a> platform.
+
+## Enabling New Relic Extension
+
+To package the New Relic extension into the Jar, follow the following steps.
+1. Add the following import to your program.
+```ballerina
+import ballerinax/newrelic as _;
+```
+
+2. Add the following to the `Ballerina.toml` when building your program.
+```toml
+[package]
+org = "my_org"
+name = "my_package"
+version = "1.0.0"
+
+[build-options]
+observabilityIncluded=true
+```
+
+To enable the extension and publish traces and metrics to New Relic, add the following to the `Config.toml` when running your program.
+
+```toml
+[ballerina.observe]
+tracingEnabled=true
+tracingProvider="newrelic"
+metricsEnabled=true
+metricsReporter="newrelic"
+
+[ballerinax.newrelic]
+apiKey="<NEW_RELIC_LICENSE_KEY>"    # Mandatory Configuration.
+tracingSamplerType="const"          # Optional Configuration. Default value is 'const'
+tracingSamplerParam=1               # Optional Configuration. Default value is 1
+tracingReporterFlushInterval=15000  # Optional Configuration. Default value is 15000 milliseconds
+tracingReporterBufferSize=10000     # Optional Configuration. Default value is 10000
+metricReporterFlushInterval=15000   # Optional Configuration. Default value is 15000 milliseconds
+metricReporterClientTimeout=10000   # Optional Configuration. Default value is 10000 milliseconds
+```
+
+User can configure the environment variable `BALLERINA_NEWRELIC_API_KEY` instead of `apiKey` in `Config.toml`.
+If both are configured, `apiKey` in `Config.toml` will be overwritten by the environment variable value.
+
+### Observe Metrics in New Relic
+
+Instead of using prometheus as an intermediate metric reporter that remote writes the metrics to New Relic,
+Ballerina New Relic Observability Extension directly publishes metrics to New Relic on the following metric API `https://metric-api.newrelic.com/metric/v1`.
+
+Instrumentation of metrics is done using the [com.newrelic.telemetry](https://github.com/newrelic/newrelic-telemetry-sdk-java).
+
+#### Available Metrics
+
+The exporter provides the following metrics.
+
+|Metric Name|Description|
+|---|---|
+|response_time_seconds_value|Response time of a HTTP request in seconds|
+|response_time_seconds_max|Maximum response time of a HTTP request|
+|response_time_seconds_min|Minimum response time of a HTTP request|
+|response_time_seconds_mean|Average response time of a HTTP request|
+|response_time_seconds_stdDev|Standard deviation of response time of a HTTP request|
+|response_time_seconds|Summary of HTTP request-response times across various time frames and quantiles|
+|response_time_nanoseconds_total_value|Response time of a HTTP request in nano seconds|
+|requests_total_value|Total number of requests|
+|response_errors_total_value|Total number of response errors|
+|inprogress_requests_value|Total number of inprogress requests|
+|kafka_publishers_value|Number of publishers in kafka|
+|kafka_consumers_value|Number of consumers in kafka|
+|kafka_errors_value|Number of errors happened while publishing in kafka|
+
+### Observe Traces in New Relic
+
+Ballerina New Relic Observability Extension directly publishes traces to New Relic on the following trace API `https://otlp.nr-data.net:4317`.
+Traces are published to New Relic on OpenTelemetry format.
+
+Instrumentation of traces is done using the [io.opentelemetry](https://github.com/open-telemetry/opentelemetry-java) and `GRPC` protocol is used send traces.