I'm trying to integrate Crux with http://materialize.io. I think/hope it'll work if I use the kafka connect plugin (with mode=doc and format=json) and materialize's "text or bytes over kafka" source (with ENVELOPE UPSERT). However I'm having trouble with the kafka connect plugin. Given the following, test.sink.txt gets created but it remains empty:

; deps.edn

{:deps
 {juxt/crux-core {:mvn/version "20.05-1.8.4-alpha"}
  juxt/crux-kafka-embedded {:mvn/version "20.05-1.8.4-alpha"}
  juxt/crux-rocksdb {:mvn/version "20.05-1.8.4-alpha"}}}

; src/foo.clj

(ns foo
  (:require
    [crux.api :as crux]
    [crux.kafka.embedded :as ek]))

(defn -main []
  (let [node (crux/start-node
               {:crux.kv/db-dir (str "data/crux-db")
                :crux.http-server/port 3000
                :crux.node/topology '[crux.standalone/topology crux.kv.rocksdb/kv-store]
                :crux.standalone/event-log-dir "data/eventlog"
                :crux.standalone/event-log-kv-store 'crux.kv.rocksdb/kv})]
    (ek/start-embedded-kafka
      #:crux.kafka.embedded{:zookeeper-data-dir "data/zk-data"
                            :kafka-log-dir "data/kafka-log"
                            :kafka-port 9092})
    (loop []
      (Thread/sleep 1000)
      (println "Submitting event")
      (crux/submit-tx node [[:crux.tx/put {:crux.db/id (java.util.UUID/randomUUID)
                                           :timestamp (java.util.Date.)
                                           :text "some event"}]])
      (recur))))

; shell

$ clj -m foo
$ cd kafka_2.12-2.3.0 # new terminal tab
$ ls libs/crux* config/local*
config/local-crux-source.properties  libs/crux-kafka-connect-19.12-1.6.1-alpha-standalone.jar
$ bin/kafka-topics.sh --create --bootstrap-server localhost:9092 \
                      --replication-factor 1 --partitions 1 --topic connect-test
$ bin/connect-standalone.sh config/connect-standalone.properties \
                            config/local-crux-source.properties \
                            config/connect-file-sink.properties