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OpenTelemetry Demo and Datadog

Tracetest is a testing tool based on OpenTelemetry that allows you to test your distributed application. It allows you to use data from distributed traces generated by OpenTelemetry to validate and assert if your application has the desired behavior defined by your test definitions.

Datadog is an observability solution for cloud-scale applications, providing solutions to monitor databases, servers, tools and services. It provides integrated distributed tracing, logs and metrics solutions and supports OpenTelemetry standards.

OpenTelemetry Demo v1.3.0 with Datadog, OpenTelemetry and Tracetest

This is a simple sample app on how to configure the OpenTelemetry Demo v1.3.0 to use Tracetest for enhancing your E2E and integration tests with trace-based testing and Datadog as a trace data store.

Prerequisites

You will need Docker and Docker Compose installed on your machine to run this sample app! Additionally, you will need a Datadog account and an API. Sign up to Datadog on their homepage by clicking on Get Started Free.

Project Structure

The project is built with Docker Compose. It contains two distinct docker-compose.yaml files.

1. OpenTelemetry Demo

The docker-compose.yaml file and .env file in the root directory are for the OpenTelemetry Demo.

2. Tracetest

The docker-compose.yaml file, collector.config.yaml, tracetest-provision.yaml, and tracetest-config.yaml in the tracetest directory are for setting up Tracetest and the OpenTelemetry Collector.

The tracetest directory is self-contained and will run all the prerequisites for enabling OpenTelemetry traces and trace-based testing with Tracetest, as well as routing all traces the OpenTelemetry Demo generates to Datadog.

Docker Compose Network

All services in the docker-compose.yaml are on the same network, defined by the networks section on each file, and will be reachable by hostname from within other services. E.g. tracetest:4317 in the collector.config.yaml will map to the tracetest service, where port 4317 is the port where Tracetest accepts traces.

OpenTelemetry Demo

The OpenDelemetry Demo is a sample microservice-based app with the purpose to demo how to correctly set up OpenTelemetry distributed tracing.

Read more about the OpenTelemetry Demo here.

The docker-compose.yaml contains 14 services.

To start the OpenTelemetry Demo by itself, run this command:

docker compose up

This will start the OpenTelemetry Demo. Open up http://localhost:8084 to make sure it's working. But, you're not sending the traces anywhere.

Let's fix this by configuring Tracetest and the OpenTelemetry Collector to forward trace data to both Lightstep and Tracetest.

Tracetest

The docker-compose.yaml in the tracetest directory is configured with three services.

  • Postgres - Postgres is a prerequisite for Tracetest to work. It stores trace data when running trace-based tests.
  • OpenTelemetry Collector - A vendor-agnostic implementation of how to receive, process and export telemetry data. To support sending traces to Datadog, we are using the contrib version, which contains vendor-related code.
  • Tracetest - Trace-based testing that generates end-to-end tests automatically from traces.
version: "3.9"

networks:
default:
name: opentelemetry-demo
driver: bridge

services:
tracetest:
restart: unless-stopped
image: kubeshop/tracetest:${TAG:-latest}
container_name: tracetest
platform: linux/amd64
ports:
- 11633:11633
extra_hosts:
- "host.docker.internal:host-gateway"
volumes:
- type: bind
source: ./tracetest-config.yaml
target: /app/tracetest.yaml
- type: bind
source: ./tracetest-provision.yaml
target: /app/provisioning.yaml
command: --provisioning-file /app/provisioning.yaml
healthcheck:
test: ["CMD", "wget", "--spider", "localhost:11633"]
interval: 1s
timeout: 3s
retries: 60
depends_on:
tt-postgres:
condition: service_healthy
otel-collector:
condition: service_started
environment:
TRACETEST_DEV: ${TRACETEST_DEV}

tt-postgres:
image: postgres:14
container_name: tt-postgres
environment:
POSTGRES_PASSWORD: postgres
POSTGRES_USER: postgres
healthcheck:
test: pg_isready -U "$$POSTGRES_USER" -d "$$POSTGRES_DB"
interval: 1s
timeout: 5s
retries: 60

otel-collector:
image: otel/opentelemetry-collector-contrib:0.68.0
container_name: otel-collector
restart: unless-stopped
command:
- "--config"
- "/otel-local-config.yaml"
volumes:
- ./tracetest/collector.config.yaml:/otel-local-config.yaml

Tracetest depends on both Postgres and the OpenTelemetry Collector. Both Tracetest and the OpenTelemetry Collector require config files to be loaded via a volume. The volumes are mapped from the root directory into the tracetest directory and the respective config files.

To start both the OpenTelemetry Demo and Tracetest we will run this command:

docker-compose -f docker-compose.yaml -f tracetest/docker-compose.yaml up

The tracetest-config.yaml file contains the basic setup of connecting Tracetest to the Postgres instance and telemetry exporter. The exporter is set to the OpenTelemetry Collector.

# tracetest-config.yaml

---
postgres:
host: postgres
user: postgres
password: postgres
port: 5432
dbname: postgres
params: sslmode=disable

telemetry:
exporters:
collector:
serviceName: tracetest
sampling: 100
exporter:
type: collector
collector:
endpoint: otel-collector:4317

server:
telemetry:
exporter: collector
applicationExporter: collector

The tracetest-provision.yaml file contains the setup of the demo APIs that Tracetest can use as an example for tests, the polling profiles that say how Tracetest should fetch traces from the data store and the configuration for the data store, in our case, Datadog.

---
type: Demo
spec:
name: "OpenTelemetry Shop"
enabled: true
type: otelstore
opentelemetryStore:
frontendEndpoint: http://frontend:8084
productCatalogEndpoint: productcatalogservice:3550
cartEndpoint: cartservice:7070
checkoutEndpoint: checkoutservice:5050

---
type: PollingProfile
spec:
name: Default
strategy: periodic
default: true
periodic:
retryDelay: 5s
timeout: 180s

---
type: DataStore
spec:
name: datadog
type: datadog

Sending Traces to Tracetest and Datadog

The collector.config.yaml explains that. It receives traces via either grpc or http. Then, exports them to Tracetest's OTLP endpoint tracetest:4317 in one pipeline, and to Datadog in another.

Make sure to add your Datadog API Key to the datadog exporter.

receivers:
otlp:
protocols:
http:
grpc:

processors:
batch: # this configuration is needed to guarantee that the data is sent correctly to Datadog
send_batch_max_size: 100
send_batch_size: 10
timeout: 10s

exporters:
# OTLP for Tracetest
otlp/tracetest:
endpoint: tracetest:4317
# Send traces to Tracetest.
# Read more in docs here: https://docs.tracetest.io/configuration/connecting-to-data-stores/opentelemetry-collector
tls:
insecure: true
# Datadog exporter
datadog:
api:
site: datadoghq.com
key: ${DATADOG_API_KEY} # Add here you API key for Datadog
# One example on how to set up a collector configuration for Datadog can be seen here:
# https://docs.datadoghq.com/opentelemetry/otel_collector_datadog_exporter/?tab=onahost

service:
pipelines:
traces/tracetest:
receivers: [otlp]
processors: [batch]
exporters: [otlp/tracetest]
traces/datadog:
receivers: [otlp]
processors: [batch]
exporters: [datadog]

Run Both the OpenTelemetry Demo App and Tracetest

To start both OpenTelemetry and Tracetest, run this command:

docker-compose -f docker-compose.yaml -f tracetest/docker-compose.yaml up

This will start your Tracetest instance on http://localhost:11633/.

Open the URL and start creating tests in the Web UI! Make sure to use the endpoints within your Docker network like http://frontend:8084/ when creating tests.

This is because your OpenTelemetry Demo and Tracetest are in the same network.

Note: View the demo section in the tracetest.config.yaml to see which endpoints from the OpenTelemetry Demo are available for running tests.

Here's a sample of a failed test run, which happens if you add this assertion:

attr:tracetest.span.duration  < 10ms

Increasing the duration to a more reasonable 500ms will make the test pass.

Run Tracetest Tests with the Tracetest CLI

First, install the CLI. Then, configure the CLI:

tracetest configure --server-url http://localhost:11633

Once configured, you can run a test against the Tracetest instance via the terminal.

Check out the http-test.yaml file.

# http-test.yaml

type: Test
spec:
id: JBYAfKJ4R
name: OpenTelemetry Shop - List Products
description: List Products available on OTel shop
trigger:
type: http
httpRequest:
url: http://frontend:8084/api/products
method: GET
headers:
- key: Content-Type
value: application/json
specs:
- selector: span[tracetest.span.type="general" name="Tracetest trigger"]
assertions:
- attr:tracetest.response.status = 200
- attr:tracetest.span.duration < 10ms
- selector: span[tracetest.span.type="rpc" name="grpc.hipstershop.ProductCatalogService/ListProducts"]
assertions:
- attr:rpc.grpc.status_code = 0
- selector: span[tracetest.span.type="rpc" name="hipstershop.ProductCatalogService/ListProducts"
rpc.system="grpc" rpc.method="ListProducts" rpc.service="hipstershop.ProductCatalogService"]
assertions:
- attr:rpc.grpc.status_code = 0

This file defines a test the same way you would through the Web UI.

To run the test, run this command in the terminal:

tracetest run test -f ./http-test.yaml

This test will fail just like the sample above due to the attr:tracetest.span.duration < 10ms assertion.

✘ OpenTelemetry Shop - List Products (http://localhost:11633/test/JBYAfKJ4R/run/3/test)
✘ span[tracetest.span.type="general" name="Tracetest trigger"]
✘ #2d1b0dcbd75b3a42
✔ attr:tracetest.response.status = 200 (200)
✘ attr:tracetest.span.duration < 10ms (24ms) (http://localhost:11633/test/JBYAfKJ4R/run/3/test?selectedAssertion=0&selectedSpan=2d1b0dcbd75b3a42)
✔ span[tracetest.span.type="rpc" name="grpc.hipstershop.ProductCatalogService/ListProducts"]
✔ #90aeab1e9db4617b
✔ attr:rpc.grpc.status_code = 0 (http://localhost:11633/test/JBYAfKJ4R/run/3/test?selectedAssertion=1)
✔ span[tracetest.span.type="rpc" name="hipstershop.ProductCatalogService/ListProducts" rpc.system="grpc" rpc.method="ListProducts" rpc.service="hipstershop.ProductCatalogService"]
✔ #44b836b092b4d708
✔ attr:rpc.grpc.status_code = 0 (http://localhost:11633/test/JBYAfKJ4R/run/3/test?selectedAssertion=2)

If you edit the duration as in the Web UI example above, the test will pass!

View Trace Spans Over Time in Datadog

To access a historical overview of all the trace spans the OpenTelemetry Demo generates, jump over to your Datadog account on APM > Traces area.

You can also drill down into a particular trace as well.

With Datadog and Tracetest, you get the best of both worlds. You can run trace-based tests and automate running E2E and integration tests against real trace data. And, use Datadog to get a historical overview of all traces your distributed application generates.

Learn more

Feel free to check out our examples in GitHub and join our Slack Community for more info!