From 4a7e82f07d1e8d7c01c0b70bfb7c452464ce6a05 Mon Sep 17 00:00:00 2001
From: Milind L <miluthra@confluent.io>
Date: Wed, 16 Jul 2025 18:21:27 +0530
Subject: [PATCH] Add auth and docker documentation

---
 INTRODUCTION.md                        |  7 +++-
 examples/node-rdkafka/docker-alpine.md | 45 +++++++++++++++-----------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/INTRODUCTION.md b/INTRODUCTION.md
index cdda0401..355a4e24 100644
--- a/INTRODUCTION.md
+++ b/INTRODUCTION.md
@@ -1102,7 +1102,10 @@ const producer = new Kafka().producer({
 });
 ```
 
-For a special case of OAuthBearer token authentication, where the token is fetched from an OIDC provider using the `client_credentials` grant type, the library provides a built-in callback, which can be set through just the configuration without any custom function required:
+For a special case of OAuthBearer token authentication where the token is fetched from an OIDC provider using the `client_credentials` or `jwt_bearer` grant type, the library provides a built-in mechanism for authentication.
+No `oauthbearer_token_refresh_cb` needs to be provided in these cases. Instead, authentication can be set through just the configuration.
+
+If using `client_credentials` grant type, you can do the following:
 
 ```js
 const producer = new Kafka().producer({
@@ -1118,6 +1121,8 @@ const producer = new Kafka().producer({
 });
 ```
 
+If using `jwt_bearer` grant type, refer to the [librdkafka documentation](https://github.com/confluentinc/librdkafka/blob/master/INTRODUCTION.md#jwt-bearer-grant-type-kip-1139).
+
 These examples are for the promisified API, but the callback-based API can be used with the same configuration settings.
 
 ## Installation Instructions
diff --git a/examples/node-rdkafka/docker-alpine.md b/examples/node-rdkafka/docker-alpine.md
index 5f407c5f..a1691a85 100644
--- a/examples/node-rdkafka/docker-alpine.md
+++ b/examples/node-rdkafka/docker-alpine.md
@@ -1,22 +1,10 @@
-When using docker to install `confluent-kafka-javascript`, you need to make sure you install appropriate library dependencies. Alpine linux is a lighter weight version of linux and does not come with the same base libraries as other distributions (like glibc).
+# Dockerfile for confluent-kafka-javascript
 
-You can see some of the differences here: https://linuxacademy.com/blog/cloud/alpine-linux-and-docker/
+A sample Dockerfile to run the `confluent-kafka-javascript` library using Node.js:
 
 ```dockerfile
-FROM node:14-alpine
-
-RUN apk --no-cache add \
-      bash \
-      g++ \
-      ca-certificates \
-      lz4-dev \
-      musl-dev \
-      cyrus-sasl-dev \
-      openssl-dev \
-      make \
-      python3
-
-RUN apk add --no-cache --virtual .build-deps gcc zlib-dev libc-dev bsd-compat-headers py-setuptools bash
+# The official (Debian-based) and Alpine-based Node.js images are both useable.
+FROM node:24
 
 # Create app directory
 RUN mkdir -p /usr/local/app
@@ -24,7 +12,26 @@ RUN mkdir -p /usr/local/app
 # Move to the app directory
 WORKDIR /usr/local/app
 
-# Install confluent-kafka-javascript
-RUN npm install confluent-kafka-javascript
-# Copy package.json first to check if an npm install is needed
+# Copy relevant files
+COPY . .
+
+# Install application dependencies, if node_modules is not already present.
+RUN npm install
+
+# Rebuild the @confluentinc/kafka-javascript package for this environment. See
+# below for more details on why this is necessary, and if you can skip this step.
+RUN rm -rf node_modules/@confluentinc/kafka-javascript
+RUN npm install @confluentinc/kafka-javascript
+
+# Start application
+CMD ["node", "index.js"]
 ```
+
+`confluent-kafka-javascript` contains platform specific binary code (to talk to the underlying C library).
+Depending on the OS, platform, architecture, and the libc type (glibc or musl), a different binary is required.
+
+The correct binary is downloaded from GitHub when installing the package for the first time, however, if you copy
+the `node_modules` directory from a different environment (e.g., your local machine) into the Docker container, it may not work correctly due to platform differences.
+
+If you can ensure that the `node_modules` directory is not copied into the Docker container, or that the platform
+where the image is built is identical to the Docker container's platform, you can skip the reinstallation step.