[paymentservice] add basic metrics support

CHANGELOG.md

@@ -138,3 +138,5 @@ significant modifications will be credited to OpenTelemetry Authors.
 ([#569](https://github.com/open-telemetry/opentelemetry-demo/pull/569))
 * Optimize GitHub Builds and fix broken emulation of featureflag
 ([#536](https://github.com/open-telemetry/opentelemetry-demo/pull/536))
+* Add basic metrics support for payment service
+([#583](https://github.com/open-telemetry/opentelemetry-demo/pull/583))

docker-compose.yml

@@ -286,6 +286,8 @@ services:
     environment:
       - PAYMENT_SERVICE_PORT
       - OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
+      - OTEL_EXPORTER_OTLP_METRICS_ENDPOINT
+      - OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE
       - OTEL_SERVICE_NAME=paymentservice
     depends_on:
       - otelcol

docs/metric_service_features.md

@@ -15,7 +15,7 @@ Emoji Legend
 | Email           | Ruby            | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |
 | Feature Flag    | Erlang / Elixir | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |
 | Frontend        | JavaScript      | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |
-| Payment         | JavaScript      | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |
+| Payment         | JavaScript      | :construction:       | :100:                  | :construction:                        | :construction: | :construction: | :construction:                     |
 | Product Catalog | Go              | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |
 | Recommendation  | Python          | :100:       | :100:                  | :construction:                        | :construction: | :construction: | :construction:                     |
 | Shipping        | Rust            | :construction:       | :construction:         | :construction:                        | :construction: | :construction: | :construction:                     |

docs/services/paymentservice.md

@@ -8,33 +8,39 @@ processed.
 
 ## Initializing OpenTelemetry
 
-It is recommended to use a Node required module when starting your NodeJS
-application to initialize the SDK and auto-instrumentation. When initializing
-the OpenTelemetry NodeJS SDK, you optionally specify which auto-instrumentation
-libraries to leverage, or make use of the `getNodeAutoInstrumentations()`
-function which includes most popular frameworks. The `tracing.js` contains all
-code required to initialize the SDK and auto-instrumentation based on standard
-OpenTelemetry environment variables for OTLP export, resource attributes, and
-service name.
+It is recommended to use wrap your app using an OpenTelemetry initialization
+wrapper when starting your NodeJS application to initialize the SDK and auto-
+instrumentation. When initializing the OpenTelemetry NodeJS SDK, you optionally
+specify which auto-instrumentation libraries to leverage, or make use of the
+`getNodeAutoInstrumentations()` function which includes most popular frameworks.
+The `opentelemetry.js` file contains all code required to initialize the SDK and
+auto-instrumentation based on standard OpenTelemetry environment variables for
+OTLP export, resource attributes, and service name. It then `require`s your app
+to start it up once the SDK is initialized.
 
 ```javascript
 const opentelemetry = require("@opentelemetry/sdk-node")
 const { getNodeAutoInstrumentations } = require("@opentelemetry/auto-instrumentations-node")
-const { OTLPTraceExporter } =  require('@opentelemetry/exporter-trace-otlp-grpc')
+const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-grpc')
+const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-grpc')
+const { PeriodicExportingMetricReader } = require('@opentelemetry/sdk-metrics');
 
 const sdk = new opentelemetry.NodeSDK({
   traceExporter: new OTLPTraceExporter(),
-  instrumentations: [ getNodeAutoInstrumentations() ]
+  instrumentations: [ getNodeAutoInstrumentations() ],
+  metricReader: new PeriodicExportingMetricReader({
+    exporter: new OTLPMetricExporter()
+  }),
 })
 
-sdk.start()
+sdk.start().then(() => require("./index"));
 ```
 
-Node required modules are loaded using the `--require` command line argument.
+You can then use `opentelemetry.js` to start your app.
 This can be done in the `ENTRYPOINT` command for the service's `Dockerfile`.
 
 ```dockerfile
-ENTRYPOINT [ "node", "--require", "./tracing.js", "./index.js" ]
+ENTRYPOINT [ "node", "./opentelemetry.js" ]
 ```
 
 ## Traces
@@ -72,7 +78,21 @@ be sure to set the span's status accordingly. You can see this in the
 
 ## Metrics
 
-TBD
+### Creating Meters and Instruments
+
+Meters can be created using the `@opentelemetry/api-metrics` package. You can
+create meters as seen below, and then use the created meter to create
+instruments.
+
+```javascript
+const { metrics } = require('@opentelemetry/api-metrics');
+
+const meter = metrics.getMeter('paymentservice');
+const transactionsCounter = meter.createCounter('app.payment.transactions')
+```
+
+Meters and Instruments are supposed to stick around. This means you should
+get a Meter or an Instrument once, and then re-use it as needed.
 
 ## Logs
 

src/paymentservice/Dockerfile

@@ -33,4 +33,4 @@ COPY ./src/paymentservice/ ./
 COPY ./pb/demo.proto ./
 
 EXPOSE ${PAYMENT_SERVICE_PORT}
-ENTRYPOINT [ "node", "--require", "./tracing.js", "./index.js" ]
+ENTRYPOINT [ "npm", "run", "start" ]

src/paymentservice/charge.js

@@ -13,16 +13,20 @@
 // limitations under the License.
 
 const {context, propagation, trace} = require('@opentelemetry/api');
+const { metrics } = require('@opentelemetry/api-metrics');
 const cardValidator = require('simple-card-validator');
 const { v4: uuidv4 } = require('uuid');
 
 const logger = require('./logger');
 const tracer = trace.getTracer('paymentservice');
+const meter = metrics.getMeter('paymentservice');
+const transactionsCounter = meter.createCounter('app.payment.transactions')
 
 module.exports.charge = request => {
   const span = tracer.startSpan('charge');
 
-  const { creditCardNumber: number,
+  const {
+    creditCardNumber: number,
     creditCardExpirationYear: year,
     creditCardExpirationMonth: month
   } = request.creditCard;
@@ -32,7 +36,7 @@ module.exports.charge = request => {
   const transactionId = uuidv4();
 
   const card = cardValidator(number);
-  const {card_type: cardType, valid } = card.getCardDetails();
+  const { card_type: cardType, valid } = card.getCardDetails();
 
   span.setAttributes({
     'app.payment.card_type': cardType,
@@ -53,7 +57,7 @@ module.exports.charge = request => {
 
   // check baggage for synthetic_request=true, and add charged attribute accordingly
   const baggage = propagation.getBaggage(context.active());
-  if (baggage && baggage.getEntry("synthetic_request") && baggage.getEntry("synthetic_request").value == "true") {
+  if (baggage && baggage.getEntry("synthetic_request") && baggage.getEntry("synthetic_request").value === "true") {
     span.setAttribute('app.payment.charged', false);
   } else {
     span.setAttribute('app.payment.charged', true);
@@ -63,6 +67,6 @@ module.exports.charge = request => {
 
   const { units, nanos, currencyCode } = request.amount;
   logger.info({transactionId, cardType, lastFourDigits, amount: { units, nanos, currencyCode }}, "Transaction complete.");
-
+  transactionsCounter.add(1, {"app.payment.currency": currencyCode})
   return { transactionId }
 }

src/paymentservice/opentelemetry.js

@@ -0,0 +1,15 @@
+const opentelemetry = require("@opentelemetry/sdk-node")
+const { getNodeAutoInstrumentations } = require("@opentelemetry/auto-instrumentations-node")
+const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-grpc')
+const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-grpc')
+const { PeriodicExportingMetricReader } = require('@opentelemetry/sdk-metrics');
+
+const sdk = new opentelemetry.NodeSDK({
+  traceExporter: new OTLPTraceExporter(),
+  instrumentations: [ getNodeAutoInstrumentations() ],
+  metricReader: new PeriodicExportingMetricReader({
+    exporter: new OTLPMetricExporter()
+  }),
+})
+
+sdk.start().then(() => require("./index"));