Demo Architecture

OpenTelemetry Demo is composed of microservices written in different programming languages that talk to each other over gRPC and HTTP; and a load generator which uses k6 to fake user traffic.

graph TD
subgraph Service Diagram
accounting(Accounting):::dotnet
ad(Ad):::java
agent(Agent):::python
cache[(Cache<br/>&#40Valkey&#41)]
cart(Cart):::dotnet
chatbot(Chatbot):::python
checkout(Checkout):::golang
currency(Currency):::cpp
email(Email):::ruby
flagd(Flagd):::golang
flagd-ui(Flagd-ui):::elixir
fraud-detection(Fraud Detection):::kotlin
frontend(Frontend):::typescript
frontend-proxy(Frontend Proxy <br/>&#40Envoy&#41):::cpp
image-provider(Image Provider <br/>&#40nginx&#41):::cpp
load-generator([Load Generator]):::golang
mcp(MCP):::python
payment(Payment):::javascript
product-catalog(Product Catalog):::golang
quote(Quote):::php
recommendation(Recommendation):::python
shipping(Shipping):::rust
queue[(queue<br/>&#40Kafka&#41)]:::java
react-native-app(React Native App):::typescript
postgresql[(astronomy-db<br/>&#40PostgreSQL&#41)]

chatbot -->|HTTP| agent
agent -.->|HTTP| frontend
agent -.->|HTTP| mcp

ad --->|gRPC| flagd

checkout -->|gRPC| currency
checkout -->|gRPC| cart
cart --> cache
cart --->|gRPC| flagd

checkout --->|gRPC| payment
checkout --->|HTTP| email
checkout -->|TCP| queue
checkout ---->|gRPC| product-catalog
checkout -->|HTTP| shipping
shipping -->|HTTP| quote

fraud-detection --->|gRPC| flagd

frontend -->|gRPC| ad
frontend ---->|gRPC| cart
frontend -->|gRPC| currency
frontend -->|gRPC| checkout
frontend -->|HTTP| shipping
frontend -->|gRPC| product-catalog
frontend --->|gRPC| recommendation

frontend-proxy -->|gRPC| flagd
frontend-proxy -->|HTTP| flagd-ui
frontend-proxy -->|HTTP| image-provider
frontend-proxy -->|HTTP| frontend
frontend-proxy -->|HTTP| chatbot

mcp -->|HTTP| frontend

payment --->|gRPC| flagd

queue -->|TCP| fraud-detection

recommendation -->|gRPC| product-catalog
recommendation ----->|gRPC| flagd

product-catalog --> postgresql

Internet -->|HTTP| frontend-proxy
load-generator -->|HTTP| frontend-proxy
react-native-app -->|HTTP| frontend-proxy
accounting --> postgresql
queue -->|TCP| accounting

end

classDef dotnet fill:#311a7f,color:white;
classDef cpp fill:#f34b7d,color:white;
classDef elixir fill:#b294bb,color:black;
classDef golang fill:#00add8,color:black;
classDef java fill:#b07219,color:white;
classDef javascript fill:#f1e05a,color:black;
classDef kotlin fill:#6b57ff,color:white;
classDef php fill:#4F5B93,color:white;
classDef python fill:#82b043,color:white;
classDef ruby fill:#701516,color:white;
classDef rust fill:#dea584,color:black;
classDef typescript fill:#e98516,color:black;

graph LR
subgraph Service Legend
  dotnetsvc(.NET):::dotnet
  cppsvc(C++):::cpp
  elixirsvc(Elixir):::elixir
  golangsvc(Go):::golang
  javasvc(Java):::java
  javascriptsvc(JavaScript):::javascript
  kotlinsvc(Kotlin):::kotlin
  phpsvc(PHP):::php
  pythonsvc(Python):::python
  rubysvc(Ruby):::ruby
  rustsvc(Rust):::rust
  typescriptsvc(TypeScript):::typescript
end

classDef dotnet fill:#311a7f,color:white;
classDef cpp fill:#f34b7d,color:white;
classDef elixir fill:#b294bb,color:black;
classDef golang fill:#00add8,color:black;
classDef java fill:#b07219,color:white;
classDef javascript fill:#f1e05a,color:black;
classDef kotlin fill:#6b57ff,color:white;
classDef php fill:#4F5B93,color:white;
classDef python fill:#82b043,color:white;
classDef ruby fill:#701516,color:white;
classDef rust fill:#dea584,color:black;
classDef typescript fill:#e98516,color:black;

Follow these links for the current state of log, metric and trace instrumentation of the demo applications.

The collector is configured in otelcol-config.yml, alternative exporters can be configured here.

When running with the observability stack, the Collector also connects to the demo’s OpAMP server through the OpAMP extension and reports its health, version, attributes, and effective configuration. Open the OpAMP UI at http://localhost:8080/opamp/ and select the Collector instance to view the reported status.

graph TB
subgraph tdf[Telemetry Data Flow]
    subgraph subgraph_padding [ ]
        style subgraph_padding fill:none,stroke:none;
        %% padding to stop the titles clashing
        subgraph od[OpenTelemetry Demo]
        ms(Microservice)
        end

        ms -.->|"OTLP<br/>gRPC"| oc-grpc
        ms -.->|"OTLP<br/>HTTP POST"| oc-http

        subgraph oc[OTel Collector]
            style oc fill:#97aef3,color:black;
            oc-grpc[/"OTLP Receiver<br/>listening on<br/>grpc://localhost:4317"/]
            oc-http[/"OTLP Receiver<br/>listening on <br/>localhost:4318<br/>"/]
            oc-proc(Processors)
            oc-spanmetrics[/"Span Metrics Connector"/]
            oc-prom[/"OTLP HTTP Exporter"/]
            oc-otlp[/"OTLP Exporter"/]
            oc-opensearch[/"OpenSearch Exporter"/]

            oc-grpc --> oc-proc
            oc-http --> oc-proc

            oc-proc --> oc-prom
            oc-proc --> oc-otlp
            oc-proc --> oc-opensearch
            oc-proc --> oc-spanmetrics
            oc-spanmetrics --> oc-prom

            oc-opamp[/"OpAMP Extension"/]

        end

        oc-prom -->|"localhost:9090/api/v1/otlp"| pr-sc
        oc-otlp -->|gRPC| ja-col
        oc-opensearch -->|HTTP| os-http

        subgraph op[OpAMP Server]
            style op fill:#a6ce39,color:black;
            op-srv["OpAMP Server"]
            op-http[/"OpAMP HTTP<br/>listening on<br/>localhost:8080/opamp/"/]

            op-srv --> op-http
        end

        oc-opamp -->|"reports status<br/>over WebSocket"| op-srv

        op-b{{"Browser<br/>OpAMP UI"}}
        op-http -->|"localhost:8080/opamp/"| op-b

        subgraph pr[Prometheus]
            style pr fill:#e75128,color:black;
            pr-sc[/"Prometheus OTLP Write Receiver"/]
            pr-tsdb[(Prometheus TSDB)]
            pr-http[/"Prometheus HTTP<br/>listening on<br/>localhost:9090"/]

            pr-sc --> pr-tsdb
            pr-tsdb --> pr-http
        end

        pr-b{{"Browser<br/>Prometheus UI"}}
        pr-http ---->|"localhost:9090/graph"| pr-b

        subgraph ja[Jaeger]
            style ja fill:#60d0e4,color:black;
            ja-col[/"Jaeger Collector<br/>listening on<br/>grpc://jaeger:4317"/]
            ja-db[(Jaeger DB)]
            ja-http[/"Jaeger HTTP<br/>listening on<br/>localhost:16686"/]

            ja-col --> ja-db
            ja-db --> ja-http
        end

        subgraph os[OpenSearch]
            style os fill:#005eb8,color:black;
            os-http[/"OpenSearch<br/>listening on<br/>localhost:9200"/]
            os-db[(OpenSearch Index)]

            os-http ---> os-db
        end

        subgraph gr[Grafana]
            style gr fill:#f8b91e,color:black;
            gr-srv["Grafana Server"]
            gr-http[/"Grafana HTTP<br/>listening on<br/>localhost:3000"/]

            gr-srv --> gr-http
        end

        pr-http --> |"localhost:9090/api"| gr-srv
        ja-http --> |"localhost:16686/api"| gr-srv
        os-http --> |"localhost:9200/api"| gr-srv

        ja-b{{"Browser<br/>Jaeger UI"}}
        ja-http ---->|"localhost:16686/search"| ja-b

        gr-b{{"Browser<br/>Grafana UI"}}
        gr-http -->|"localhost:3000/dashboard"| gr-b
    end
end

Find the Protocol Buffer Definitions in the /pb/ directory.