> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Demo Env file > Guide to exporting pod environment variables with Telepresence into a .env file and loading them with dotenv so local processes receive API_URL and behave like in-cluster pods In this lesson you will reproduce and fix a common problem that occurs when using Telepresence to intercept a Kubernetes deployment: your locally running process fails because a pod environment variable containing the inventory service URL (`API_URL`) is not present on your workstation. This guide walks through the failure scenario, explains why it happens, and shows how to export pod environment variables with Telepresence into a `.env` file and consume them locally with `dotenv`. ## Problem overview * The Kubernetes Deployment sets `API_URL` in the container environment to point at the in-cluster inventory service. * When you create a Telepresence intercept and run the application locally, those pod environment variables are not automatically available to the local process. * The local process then attempts to call the inventory service with an undefined URL and throws `ERR_INVALID_URL`. Example error when `API_URL` is undefined: ```text theme={null} Error [ERR_INVALID_URL]: Invalid URL: undefined?product_ids=1,2,3 at onParseError (internal/url.js:263:9) at new URL (internal/url.js:339:5) ... { code: 'ERR_INVALID_URL', input: 'undefined?product_ids=1,2,3' } ``` Reproducing snippet that fails when `apiURL` is undefined: ```javascript theme={null} const products = []; app.get("/", async (req, res) => { try { const productIds = req.query.product_ids; console.log(productIds); const idsArray = productIds.split(",").map((id) => parseInt(id.trim(), 10)); console.log(idsArray); const filteredProducts = products.filter((product) => idsArray.includes(product.id) ); console.log(filteredProducts); // If apiURL is undefined, this fetch will throw ERR_INVALID_URL const response = await fetch(`${apiURL}?product_ids=${idsArray.join(",")}`); if (!response.ok) { throw new Error(`HTTP error! Status: ${response.status}`); } const inventory = await response.json(); // ... respond with combined product + inventory data } catch (err) { console.error(err); res.status(500).send(err.message); } }); ``` Note: the snippet above references `apiURL` directly; unless you set `apiURL` from `process.env.API_URL` the variable will be `undefined` and the request URL will be invalid. ## Deployment manifest example (shows API\_URL set in the pod) ```yaml theme={null} spec: template: spec: containers: - name: products volumeMounts: - name: db-config mountPath: /tmp ports: - containerPort: 3000 name: web env: - name: "API_URL" value: "http://inventory-service:3000/" --- apiVersion: v1 kind: Service metadata: name: products-service spec: type: LoadBalancer ``` ## Why it fails when intercepting * The Deployment configures `API_URL` for the container when running in-cluster. * Telepresence intercepts by stopping the real pod traffic and routing traffic to your workstation. It does not automatically inject the pod's environment variables into your shell. * Your local process therefore does not have the same environment (internal DNS names, service ports), causing service calls to fail. ## Solution overview Use Telepresence's `--env-file` option to export the pod environment to a file (commonly named `.env`), then load that file into your local Node.js process with a library such as `dotenv`. This ensures your local process sees the same values (for example, `API_URL`) as the in-cluster pod. ## Step-by-step reproduction and fix 1. Make sure there's no existing intercept for the workload: ```bash theme={null} telepresence list telepresence leave products-depl ``` 2. Create an intercept and ask Telepresence to write the pod's environment to a file (by convention `.env`): ```bash theme={null} telepresence intercept products-depl -p 8000 --env-file .env ``` Sample Telepresence output: ```text theme={null} Using Deployment products-depl Intercept name : products-depl State : ACTIVE Workload kind : Deployment Destination : 127.0.0.1:8000 Service Port Identifier : 3000/TCP Volume Mount Point : /tmp/telfs-3110725221 Intercepting : all TCP connections ``` 3. Telepresence will create the `.env` file in your current directory. It contains all the pod environment variables, for example: ```dotenv theme={null} API_URL=http://inventory-service:3000/ AUTH_SERVICE_PORT=tcp://10.100.10.52:3000 AUTH_SERVICE_PORT_3000_TCP=tcp://10.100.10.52:3000 AUTH_SERVICE_PORT_3000_TCP_ADDR=10.100.10.52 AUTH_SERVICE_PORT_3000_TCP_PORT=3000 AUTH_SERVICE_PORT_3000_TCP_PROTO=tcp AUTH_SERVICE_SERVICE_HOST=10.100.10.52 AUTH_SERVICE_SERVICE_PORT=3000 A_TELEPRESENCE_MOUNTS=/tmp:/var/run/secrets/kubernetes.io/serviceaccount INVENTORY_SERVICE_PORT=tcp://10.100.246.69:3000 INVENTORY_SERVICE_PORT_3000_TCP=tcp://10.100.246.69:3000 INVENTORY_SERVICE_PORT_3000_TCP_ADDR=10.100.246.69 INVENTORY_SERVICE_PORT_3000_TCP_PORT=3000 INVENTORY_SERVICE_PORT_3000_TCP_PROTO=tcp INVENTORY_SERVICE_SERVICE_HOST=10.100.246.69 INVENTORY_SERVICE_SERVICE_PORT=3000 KUBERNETES_PORT=tcp://10.100.0.1:443 KUBERNETES_PORT_443_TCP=tcp://10.100.0.1:443 KUBERNETES_PORT_443_TCP_ADDR=10.100.0.1 ``` 4. Update your local Node.js application to load `.env` and override any existing environment variables so the local process uses the same values as the pod. Example Express server that uses `dotenv` and reads `API_URL` from `process.env`: ```javascript theme={null} // Load environment variables from .env and override any existing values require('dotenv').config({ override: true }); const express = require("express"); const app = express(); const port = 8000; // Ensure we use the environment variable provided by Telepresence (.env) const apiURL = process.env.API_URL; console.log("API_URL:", apiURL); const products = [ { id: 1, name: "iphone 14", price: 900, category: "electronics", onSale: false }, { id: 2, name: "pixel 7", price: 600, category: "electronics", onSale: true } ]; app.get("/", async (req, res) => { try { const productIds = req.query.product_ids || ''; const idsArray = productIds .split(",") .map((id) => parseInt(id.trim(), 10)) .filter(Number.isFinite); const filteredProducts = products.filter((product) => idsArray.includes(product.id) ); // apiURL should now be defined from process.env.API_URL const response = await fetch(`${apiURL}?product_ids=${idsArray.join(",")}`); if (!response.ok) { throw new Error(`HTTP error! Status: ${response.status}`); } const inventory = await response.json(); res.json({ products: filteredProducts, inventory }); } catch (err) { console.error(err); res.status(500).send(err.message); } }); app.listen(port, () => { console.log(`Products service listening at http://localhost:${port}`); }); ``` Once you have the `.env` file created by Telepresence and you run your local server with the code above, requests that require the inventory service should succeed because `API_URL` is now defined as it was in-cluster. Node runtime note: The example uses global `fetch` — available in Node 18+. If you are on an older Node version, install and import `node-fetch` (or upgrade Node) before using `fetch`. ## Quick reference: Telepresence commands and files | Purpose | Command / File | Notes | | - | - | - | | List current intercepts | `telepresence list` | Shows active intercepts and statuses | | Remove an intercept | `telepresence leave products-depl` | Replace `products-depl` with your intercept name | | Create intercept and export pod env | `telepresence intercept products-depl -p 8000 --env-file .env` | `--env-file` writes pod env vars to `.env` | | Local env file | `.env` | Contains `API_URL` and other in-cluster env values; do not commit | ## Summary * The Deployment configured `API_URL` in the pod, but when you intercept and run locally you must provide those same environment variables on your workstation. * Telepresence's `--env-file` option extracts pod environment variables to a file (commonly `.env`). * Use a library such as `dotenv` to load that file into your local process so the local behavior matches the in-cluster environment. Add your `.env` file to `.gitignore` and avoid committing it. The `.env` file may contain internal IPs and service endpoints that should not be checked into source control. ## Links and references * Telepresence (official project): [https://www.telepresence.io/](https://www.telepresence.io/) * Telepresence docs: [https://www.telepresence.io/docs/](https://www.telepresence.io/docs/) * dotenv npm package: [https://www.npmjs.com/package/dotenv](https://www.npmjs.com/package/dotenv) * Kubernetes documentation: [https://kubernetes.io/docs/](https://kubernetes.io/docs/) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.