Environment variable convention

<INTERFACE>_<KEY>_<DIRECTION>

Part	Rule	Example
<INTERFACE>	Data interface type name, upper case	kafka → KAFKA
<KEY>	Parameter key, upper case, non-alphanumerics → _	bootstrap_servers → BOOTSTRAP_SERVERS
<DIRECTION>	INPUT for data inputs, OUTPUT for data outputs	INPUT

Rules:

• One variable per parameter of every connected resource, empty values included.
• Derived variables override processor parameters with the same name.
• Kafka topic_id values have spaces replaced by underscores.
• Logstash Pipeline processors do not receive variables; their resources become pipeline sections.
• The editor shows the exact list under Derived Environment Variables in each processor form.

Examples

# kafka input
KAFKA_BOOTSTRAP_SERVERS_INPUT=kafka:9092
KAFKA_SECURITY_PROTOCOL_INPUT=PLAINTEXT
KAFKA_TOPIC_ID_INPUT=telemetry-raw

# elasticsearch output
ELASTICSEARCH_HOSTS_OUTPUT=elasticsearch:9200
ELASTICSEARCH_SCHEME_OUTPUT=http
ELASTICSEARCH_INDEX_OUTPUT=alerts

# rabbitmq output
RABBITMQ_HOST_OUTPUT=rabbitmq
RABBITMQ_PORT_OUTPUT=5672
RABBITMQ_EXCHANGE_OUTPUT=events
RABBITMQ_EXCHANGE_TYPE_OUTPUT=direct

# mqtt input
MQTT_BROKER_INPUT=tcp://broker
MQTT_PORT_INPUT=1883
MQTT_TOPIC_INPUT=sensor/data

All keys per type: Interface types. How to consume them: Writing processors.