Suppress datomic transactions to prod from dev

dev.clj

(defn suppress-datomic-transactions-to-prod [config]
  (when (str/starts-with? (:datomic-uri config) "datomic:ddb://")
    (println "Warning! Suppressing transactions to production datomic from dev environment. Check your config.")
    (let [the-conn (d/connect (:datomic-uri config))]
      (alter-var-root (var datomic.api/transact)
                      (fn [transact]
                        (fn [conn txs]
                          (if (= conn the-conn)
                            (do (log/warn "Suppressed datomic transaction to production.")
                                (let [db (d/db conn)] (future {:db-after db :db-before db :tx-data nil})))
                            (transact conn txs))))))))

SQL and Cassndra users will be disappointed with these semantics. :-)