wip

Signed-off-by: kvmw <mshamsi@broadcom.com>

Author: kvmw

.cfignore

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+# Ignore everything except what we need
+*
+!greeter-messages/
+!greeter/
+!manifest.yml 

README.md

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+# Service Registry Node.js sample
+
+![CI](https://github.com/spring-cloud-services-samples/greeting-nodejs/actions/workflows/ci.yml/badge.svg)
+
+Sample Node.js application demonstrating the use of Service Registry in Tanzu Platform for Cloud Foundry.
+
+For information on the Service Registry product in Tanzu Platform for Cloud Foundry, please [see the documentation](https://techdocs.broadcom.com/us/en/vmware-tanzu/spring/spring-cloud-services-for-cloud-foundry/3-3/scs-tanzu/service-registry-index.html).
+
+## Building and Deploying
+
+- Create a Service Registry instance:
+
+```
+ cf create-service p.service-registry standard greeter-service-registry
+```
+
+- Install dependencies
+
+```
+ npm install
+```
+
+- Push the `greeter-messages` application:
+
+```
+ cd packages/greeter-messages && cf push
+```
+
+- Push the `greeter` application:
+
+```
+ cd packages/greeter && cf push
+```
+
+## Trying It Out
+
+Call `[ROUTE]/hello`, where `[ROUTE]` is the route bound to the `greeter` application, with optional `name` and `salutation` parameters.
+
+```
+ $ curl -k greeter.apps.example.cf-app.com/hello?name=John
+ Hello, John!
+```

greeter-messages/Procfile

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+web: gunicorn --bind 0.0.0.0:$PORT app:app

greeter-messages/app.py

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+import os
+from flask import Flask, request
+from eureka_client import EurekaServerClient
+
+
+app = Flask(__name__)
+
+@app.route('/greeting')
+def greeting():
+    salutation = request.args.get('salutation', 'Hello')
+    name = request.args.get('name', 'Bob')
+    
+    return f"{salutation}, {name}!"
+
+if __name__ == '__main__':
+    port = int(os.getenv("PORT", '8080'))
+    eureka_client = EurekaServerClient(port)
+    asyncio.run(eureka_client.start())
+    app.run(host='0.0.0.0', port=port)

greeter-messages/eureka_client.py

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+from cfenv import AppEnv
+from oauth2 import OAuth2Client
+from py_eureka_client.eureka_client import EurekaClient
+
+class EurekaServerClient:
+    def __init__(self, port: int):
+        self.env = AppEnv()
+        self.oauth_client = None
+        self.credentials = None
+
+        service_registry = self.env.get_service(label="p.service-registry")
+        if not service_registry:
+            raise ValueError("No 'p.service-registry' service instance found.")
+
+        self.credentials = service_registry.credentials
+        self.oauth_client = OAuth2Client(
+            client_id=self.credentials['client_id'],
+            client_secret=self.credentials['client_secret'],
+            access_token_uri=self.credentials['access_token_uri'],
+            on_err=self.on_err
+        )
+
+        self.client = EurekaClient(
+            app_name=self.env.name,
+            instance_port=port,
+            eureka_server=self.credentials['uri']
+        )
+
+    def on_err(err_type: str, err: Exception):
+        print(f"{err_type}::{err}")
+
+    async def start(self):
+        await self.client.start()
+
+    async def stop(self):
+        await self.client.stop()

greeter-messages/oauth2.py

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+import time
+from typing import Optional
+import requests
+
+class OAuth2Client:
+    """OAuth 2.0 client for handling client credentials flow with token caching"""
+
+    def __init__(self, client_id: str, client_secret: str, access_token_uri: str):
+        self.client_id = client_id
+        self.client_secret = client_secret
+        self.access_token_uri = access_token_uri
+        self.access_token: Optional[str] = None
+        self.token_expires_at: Optional[float] = None
+
+    def _is_token_expired(self, buffer_seconds: int = 30) -> bool:
+        """Check if the current token is expired or will expire soon"""
+        if not self.access_token or not self.token_expires_at:
+            return True
+
+        # Add buffer time to refresh token before it actually expires
+        return time.time() >= (self.token_expires_at - buffer_seconds)
+
+    def _request_new_token(self) -> str:
+        """Request a new access token from the OAuth server"""
+        # Prepare token request
+        token_data = {
+            'grant_type': 'client_credentials',
+            'client_id': self.client_id,
+            'client_secret': self.client_secret
+        }
+
+        headers = {
+            'Content-Type': 'application/x-www-form-urlencoded'
+        }
+
+        try:
+            response = requests.post(
+                self.access_token_uri,
+                data=token_data,
+                headers=headers,
+                timeout=30
+            )
+            response.raise_for_status()
+
+            token_response = response.json()
+            self.access_token = token_response.get('access_token')
+
+            # Calculate expiration time
+            expires_in = token_response.get('expires_in', 3600)  # Default to 1 hour
+            self.token_expires_at = time.time() + expires_in
+
+            if not self.access_token:
+                raise ValueError("No access token received from OAuth server")
+
+            return self.access_token
+        except requests.exceptions.RequestException as e:
+            raise ValueError(f"Failed to get access token: {e}") from e
+
+    def get_access_token(self) -> str:
+        """Get OAuth 2.0 access token using client credentials flow"""
+        # Check if we have a valid cached token
+        if not self._is_token_expired():
+            return self.access_token
+        # Token is expired or doesn't exist, get a new one
+        return self._request_new_token()

greeter-messages/requirements.txt

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+astroid==3.3.11
+blinker==1.9.0
+certifi==2025.8.3
+cfenv==0.5.3
+charset-normalizer==3.4.2
+click==8.2.1
+dill==0.4.0
+dnspython==2.7.0
+Flask==3.1.1
+furl==2.1.4
+gunicorn==23.0.0
+idna==3.10
+ifaddr==0.2.0
+isort==6.0.1
+itsdangerous==2.2.0
+Jinja2==3.1.6
+MarkupSafe==3.0.2
+mccabe==0.7.0
+orderedmultidict==1.0.1
+packaging==25.0
+platformdirs==4.3.8
+py_eureka_client==0.11.13
+pylint==3.3.7
+python-dotenv==1.0.0
+requests==2.31.0
+six==1.17.0
+tomlkit==0.13.3
+urllib3==2.5.0
+Werkzeug==3.1.3

greeter/Procfile

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+web: gunicorn --bind 0.0.0.0:$PORT app:app

greeter/app.py

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+import os
+from flask import Flask, request
+from shared import EurekaServerClient
+
+app = Flask(__name__)
+
+@app.route('/greet')
+def greet():
+    name = request.args.get('name', 'World')
+    return f"Greetings, {name}!"
+
+if __name__ == '__main__':
+    port = int(os.getenv("PORT", '8080'))
+    eureka_client = EurekaServerClient(port)
+    eureka_client.start()
+    app.run(host='0.0.0.0', port=port) 

greeter/requirements.txt

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+astroid==3.3.11
+blinker==1.9.0
+certifi==2025.8.3
+cfenv==0.5.3
+charset-normalizer==3.4.2
+click==8.2.1
+dill==0.4.0
+Flask==3.1.1
+furl==2.1.4
+gunicorn==23.0.0
+idna==3.10
+isort==6.0.1
+itsdangerous==2.2.0
+Jinja2==3.1.6
+MarkupSafe==3.0.2
+mccabe==0.7.0
+orderedmultidict==1.0.1
+packaging==25.0
+platformdirs==4.3.8
+pylint==3.3.7
+python-dotenv==1.0.0
+requests==2.31.0
+six==1.17.0
+tomlkit==0.13.3
+urllib3==2.5.0
+Werkzeug==3.1.3