Aiven Kafka Setup (avn CLI)
End-to-end workflow for creating an Apache Kafka service on Aiven using the avn CLI, with SASL_SSL authentication, Avro Schema Registry, and a working Java or Python producer/consumer example that reads from CSV and writes to Kafka.
IMPORTANT: This skill ALWAYS creates a fully working example (Java by default). Steps 1–3 are all mandatory. Never stop after creating the service — you MUST also build the example project, generate test data, and run the producer + consumer end-to-end.
Step 1: Prerequisites
1.1 Verify avn CLI login
Run the following to check if the user is logged in:
avn user infoIf the command fails, instruct the user:
You are not logged in to the Aiven CLI. Please run:
avn user login <your-email>
Then confirm when you are logged in.STOP and wait for the user to confirm login before proceeding.
1.2 Required tools
Verify the following are installed:
avn(Aiven CLI) - At least version 4.7.0 or later is required.jq(JSON processing)- For Java:
java(17+),mvn - For Python:
python3(3.9+),pip
Missing Requirements Policy:
- If a library or CLI tool (like
avn) is missing, advise the user on how to install it (e.g.,python3 -m pip install aiven-clientforavn). However, check first ifpython3is available before suggesting apipcommand. - If a core language runtime (
python3orjava) is requested but missing, interrupt the flow immediately. Do NOT advise the user on how to install programming languages.
Step 2: Create the Kafka Service and Export Environment Variables
Follow SERVICE_CREATION_AVN.md sections 1–4 in order:
- Choose a region — ask the user with AskQuestion, mapping their choice to the EXACT
CLOUD_NAMEfrom the table in SERVICE_CREATION_AVN.md. - Choose a plan — default
startup-4; never usefree-0orstartup-2. - Run the setup script — a single command creates the service, users, ACLs, schema, extracts all connection details, and writes them to
env.sh. - Source
env.sh— loadsKAFKA_HOST,KAFKA_PORT,SCHEMA_REGISTRY_URL,AVNADMIN_PASS,PRODUCER_PASSWORD,CONSUMER_PASSWORDinto the shell.
bash scripts/setup_aiven_kafka.sh <name> <CLOUD_NAME> <plan> 4.1
source env.shCRITICAL: Do NOT read or catenv.shin the agent context — it contains passwords. Onlysourceit and verify passwords by${#VAR}(length).
Step 3: Create and Run the Working Example
MANDATORY: This step is NOT optional. After the Kafka service is running and environment variables are exported, you MUST create a working producer/consumer example, compile/install it, generate test data, and run it end-to-end. Default language is Java unless the user explicitly requests Python.
3.1 Ask the user which language to use
Use the AskQuestion tool:
Prompt: "Which language for the producer/consumer example?"
Options:
- Java (default, recommended)
- PythonIf the user requests a language other than Java or Python, warn them:
"Results with languages other than Java or Python are unpredictable. It is recommended to use Java or Python for reliable results."
If the user does not answer or skips, default to Java.
3.2 Copy templates into the workspace
The templates live under this skill's templates/ directory. They MUST be copied to the workspace root so the run scripts can find them at the expected relative paths.
# Copy from the skill directory into the workspace root
cp -r <SKILL_DIR>/templates/ <WORKSPACE_ROOT>/templates/
cp -r <SKILL_DIR>/scripts/ <WORKSPACE_ROOT>/scripts/After copying, verify the files exist:
ls templates/order.avsc
ls templates/producer_consumer_java/Producer.java # if Java
ls templates/producer_consumer_python/producer.py # if Python
ls scripts/run_producer.sh scripts/run_consumer.sh3.3 Generate test data
Run the data generator (no external dependencies):
python3 scripts/generate_orders.pyThis creates orders.csv with 20 rows in the format id,user_id,product,price. Verify it was created:
wc -l orders.csv # should show 21 (1 header + 20 data rows)3.4 Build the project
Java (default)
Set up the Maven source tree and compile:
JAVA_DIR="templates/producer_consumer_java"
mkdir -p "$JAVA_DIR/src/main/java/com/aiven/demo"
cp "$JAVA_DIR/Producer.java" "$JAVA_DIR/src/main/java/com/aiven/demo/"
cp "$JAVA_DIR/Consumer.java" "$JAVA_DIR/src/main/java/com/aiven/demo/"
cp "$JAVA_DIR/Order.java" "$JAVA_DIR/src/main/java/com/aiven/demo/"
mvn -f "$JAVA_DIR/pom.xml" package -DskipTestsVerify the JAR was created:
ls "$JAVA_DIR/target/kafka-orders-demo-1.0-SNAPSHOT.jar"If compilation fails, check that java (17+) and mvn are installed.
Python (if selected)
Install dependencies:
python3 -m pip install -r templates/producer_consumer_python/requirements.txtVerify the install succeeded:
python3 -c "import confluent_kafka; print(confluent_kafka.version())"3.5 Run the producer (start FIRST)
The producer MUST run first to publish messages into Kafka. The consumer reads them afterwards (the consumer uses auto.offset.reset=earliest, so it will pick up all messages from the beginning of the topic regardless of when it starts).
bash scripts/run_producer.sh <java|python>Wait for the producer to finish (it will print "Done. Produced 20 messages.").
3.6 Run the consumer
After the producer has finished, start the consumer to read and process the messages:
bash scripts/run_consumer.sh <java|python>The consumer will read all 20 messages (starting from the earliest offset), write them to orders_completed.csv, and then exit (both Java and Python exit automatically after consuming the expected 20 records).
3.7 Verify output
python3 scripts/verify_output.pyThis checks that orders_completed.csv has 20 rows with correct columns and all completed_at timestamps populated.
If verification fails, check:
- The producer finished successfully before the consumer was started
- Environment variables (
KAFKA_HOST,KAFKA_PORT, etc.) are all set - The
cert/ca.pemfile exists - For Java: the JAR exists in
templates/producer_consumer_java/target/ - For Python:
confluent_kafkais installed
Step 4: Teardown Information
DO NOT run teardown automatically. Instead, inform the user how to clean up when they are ready:
When you're done with the demo, you can tear down the service by running: ``bash bash scripts/teardown.sh "$KAFKA_SERVICE"`This will delete the Aiven Kafka service, remove the localcert/` directory, and clean up generated CSV files.
For detailed avn CLI command reference and troubleshooting, see reference.md.
File Reference
| File | Purpose |
|---|---|
| SERVICE_CREATION_AVN.md | Region/plan selection (interactive), then delegates to setup script |
| reference.md | avn CLI cheat sheet, region map, troubleshooting |
| templates/order.avsc | Avro schema for orders topic |
| templates/producer_consumer_java/ | Java Producer + Consumer + pom.xml |
| templates/producer_consumer_python/ | Python producer + consumer + requirements.txt |
| scripts/generate_orders.py | Generate orders.csv (20 rows) |
| scripts/setup_aiven_kafka.sh | Full setup: service, users, ACLs, schema, env.sh |
| scripts/run_producer.sh | Run producer (Java or Python) |
| scripts/run_consumer.sh | Run consumer (Java or Python) |
| scripts/verify_output.py | Validate orders_completed.csv |
| scripts/teardown.sh | Delete service and clean up |