Producer Guide

Learn how to produce messages to Danube topics. 📤

Basic Usage

Simple Message

danube-cli produce \
  --service-addr http://localhost:6650 \
  --message "Hello, World!"

Sends one message to the default topic /default/test_topic.

Custom Topic

danube-cli produce \
  -s http://localhost:6650 \
  -t /default/orders \
  -m "Order received"

Using Short Flags

danube-cli produce -s http://localhost:6650 -t /default/events -m "Quick message"

Message Content Types

Text Messages

danube-cli produce -s http://localhost:6650 -m "Simple text message"

JSON Messages

danube-cli produce \
  -s http://localhost:6650 \
  -m '{"user_id":"123","action":"login","timestamp":"2024-01-15T10:30:00Z"}'

Binary Files

# Send an image
danube-cli produce -s http://localhost:6650 --file image.png

# Send any binary file
danube-cli produce -s http://localhost:6650 --file data.bin

Multiple Messages

Send Multiple Times

danube-cli produce \
  -s http://localhost:6650 \
  -m "Repeated message" \
  --count 10

With Interval

# Send 100 messages with 500ms delay between each
danube-cli produce \
  -s http://localhost:6650 \
  -m "Message" \
  --count 100 \
  --interval 500

Rapid Fire

# Minimum interval is 100ms
danube-cli produce \
  -s http://localhost:6650 \
  -m "Fast message" \
  --count 1000 \
  --interval 100

Message Attributes

Single Attribute

danube-cli produce \
  -s http://localhost:6650 \
  -m "Alert!" \
  --attributes "priority:high"

Multiple Attributes

danube-cli produce \
  -s http://localhost:6650 \
  -m "User action" \
  --attributes "user_id:123,region:us-west,priority:high"

Schema-Based Production

With Pre-Registered Schema (Latest Version)

# First, register the schema (one time)
danube-cli schema register orders \
  --schema-type json_schema \
  --file order-schema.json

# Produce with schema validation (uses latest version)
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/orders \
  --schema-subject orders \
  -m '{"order_id":"ord_123","amount":99.99,"currency":"USD"}'

Pin to Specific Schema Version

Use a specific version instead of latest (useful for compatibility testing or controlled rollouts):

# Use version 2 of the schema
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/orders \
  --schema-subject orders \
  --schema-version 2 \
  -m '{"order_id":"ord_456","amount":149.99,"currency":"USD"}'

Use Minimum Schema Version

Require a minimum schema version or newer:

# Use version 3 or newer
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/orders \
  --schema-subject orders \
  --schema-min-version 3 \
  -m '{"order_id":"ord_789","amount":199.99,"currency":"USD"}'

Version Control Notes: - --schema-subject alone uses the latest version - --schema-version pins to a specific version - --schema-min-version uses the specified version or newer - Cannot use both --schema-version and --schema-min-version together

Auto-Register Schema

# Schema will be registered automatically if it doesn't exist
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/events \
  --schema-file event-schema.json \
  --schema-type json_schema \
  -m '{"event":"user_signup","user_id":"user_456"}'

Schema Types

JSON Schema:

danube-cli produce \
  --schema-subject my-schema \
  --schema-type json_schema \
  -m '{"key":"value"}'

Avro:

danube-cli produce \
  --schema-subject my-avro-schema \
  --schema-type avro \
  --file message.avro

Protobuf:

danube-cli produce \
  --schema-subject my-proto-schema \
  --schema-type protobuf \
  --file message.pb

Partitioned Topics

Create Partitioned Topic

# Specify number of partitions
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/events \
  --partitions 8 \
  -m "Partitioned message"

High Throughput Example

# 16 partitions for parallel processing
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/high-volume \
  --partitions 16 \
  --schema-subject events \
  -m '{"event":"data"}' \
  --count 10000 \
  --interval 100

Reliable Delivery

Enable Reliable Delivery

# Messages are persisted to disk before acknowledgment
danube-cli produce \
  -s http://localhost:6650 \
  -m "Critical message" \
  --reliable

Reliable + Partitioned

danube-cli produce \
  -s http://localhost:6650 \
  -t /default/transactions \
  --partitions 4 \
  --reliable \
  --schema-subject transactions \
  -m '{"tx_id":"tx_789","amount":1000.00}'

Practical Examples

E-Commerce Orders

# Register order schema
danube-cli schema register orders \
  --schema-type json_schema \
  --file order-schema.json

# Send order
danube-cli produce \
  -s http://localhost:6650 \
  -t /default/orders \
  --schema-subject orders \
  --reliable \
  -m '{
    "order_id":"ord_123",
    "customer_id":"cust_456",
    "items":[{"sku":"ITEM1","qty":2,"price":29.99}],
    "total":59.98
  }'

Event Streaming

# High-volume event stream
danube-cli produce \
  -s http://localhost:6650 \
  -t /analytics/events \
  --partitions 16 \
  --schema-subject user-events \
  -m '{"event":"page_view","user_id":"user_789","page":"/home"}' \
  --count 100000 \
  --interval 100

IoT Sensor Data

# Send sensor readings
danube-cli produce \
  -s http://localhost:6650 \
  -t /iot/sensors \
  --attributes "sensor_id:temp_001,location:warehouse-a" \
  -m '{"temperature":22.5,"humidity":45,"timestamp":"2024-01-15T10:30:00Z"}' \
  --count 1440 \
  --interval 60000  # Every minute

Log Aggregation

# Send application logs
danube-cli produce \
  -s http://localhost:6650 \
  -t /logs/application \
  --attributes "app:api-server,env:production,level:error" \
  -m '{"timestamp":"2024-01-15T10:30:00Z","message":"Database connection failed","stack_trace":"..."}'

Command Reference

All Producer Flags

Flag	Short	Description	Default
`--service-addr`	`-s`	Broker URL	`http://127.0.0.1:6650`
`--topic`	`-t`	Topic name	`/default/test_topic`
`--message`	`-m`	Message content	Required*
`--file`	`-f`	Binary file path	-
`--producer-name`	`-n`	Producer name	`test_producer`
`--schema-subject`	-	Schema subject (latest version)	-
`--schema-version`	-	Pin to specific schema version	-
`--schema-min-version`	-	Use minimum version or newer	-
`--schema-file`	-	Schema file (auto-register)	-
`--schema-type`	-	Schema type	-
`--count`	`-c`	Number of messages	`1`
`--interval`	`-i`	Interval in ms	`500`
`--partitions`	`-p`	Number of partitions	-
`--attributes`	`-a`	Message attributes	-
`--reliable`	-	Reliable delivery	`false`

*Required unless --file is provided