Print warning when running with H2

project.clj

@@ -154,10 +154,7 @@
      [lein-bikeshed "0.4.1"]                                          ; Linting
      [lein-check-namespace-decls "1.0.1"]                             ; lints namespace declarations
      [lein-environ "1.1.0"]                                           ; easy access to environment variables
-     [lein-expectations "0.0.8"]                                      ; run unit tests with 'lein expectations'
-     ;; TODO - should this be moved to the new RING profile?
-     [lein-ring "0.12.5"                                              ; start the HTTP server with 'lein ring server'
-      :exclusions [org.clojure/clojure]]]
+     [lein-expectations "0.0.8"]]                                     ; run unit tests with 'lein expectations'
 
     :env      {:mb-run-mode "dev"}
     :jvm-opts ["-Dlogfile.path=target/log"]
@@ -183,7 +180,9 @@
    [:exclude-tests {}]
 
    :ring
-   [:exclude-tests {}]
+   [:exclude-tests
+    {:dependencies
+     [[lein-ring "0.12.5" :exclusions [org.clojure/clojure]]]}]       ; start the HTTP server with 'lein ring server'
 
    :with-include-drivers-middleware
    {:plugins

src/metabase/db.clj

@@ -89,25 +89,34 @@
   (or (:type @connection-string-details)
       (config/config-kw :mb-db-type)))
 
-(def db-connection-details
+(def ^:private db-connection-details
   "Connection details that can be used when pretending the Metabase DB is itself a `Database` (e.g., to use the Generic
   SQL driver functions on the Metabase DB itself)."
-  (delay (or @connection-string-details
-             (case (db-type)
-               :h2       {:type     :h2                               ; TODO - we probably don't need to specifc `:type` here since we can just call (db-type)
-                          :db       @db-file}
-               :mysql    {:type     :mysql
-                          :host     (config/config-str :mb-db-host)
-                          :port     (config/config-int :mb-db-port)
-                          :dbname   (config/config-str :mb-db-dbname)
-                          :user     (config/config-str :mb-db-user)
-                          :password (config/config-str :mb-db-pass)}
-               :postgres {:type     :postgres
-                          :host     (config/config-str :mb-db-host)
-                          :port     (config/config-int :mb-db-port)
-                          :dbname   (config/config-str :mb-db-dbname)
-                          :user     (config/config-str :mb-db-user)
-                          :password (config/config-str :mb-db-pass)}))))
+  (delay
+   (when (= (db-type) :h2)
+     (log/warn
+      (u/format-color 'red
+          (str
+           (trs "WARNING: Using Metabase with an H2 application database is not recomended for production deployments.")
+           (trs "For production deployments, we highly recommend using Postgres, MySQL, or MariaDB instead.")
+           (trs "If you decide to continue to use H2, please be sure to back up the database file regularly.")
+           (trs "See https://metabase.com/docs/latest/operations-guide/start.html#migrating-from-using-the-h2-database-to-mysql-or-postgres for more information.")))))
+   (or @connection-string-details
+       (case (db-type)
+         :h2       {:type     :h2 ; TODO - we probably don't need to specifc `:type` here since we can just call (db-type)
+                    :db       @db-file}
+         :mysql    {:type     :mysql
+                    :host     (config/config-str :mb-db-host)
+                    :port     (config/config-int :mb-db-port)
+                    :dbname   (config/config-str :mb-db-dbname)
+                    :user     (config/config-str :mb-db-user)
+                    :password (config/config-str :mb-db-pass)}
+         :postgres {:type     :postgres
+                    :host     (config/config-str :mb-db-host)
+                    :port     (config/config-int :mb-db-port)
+                    :dbname   (config/config-str :mb-db-dbname)
+                    :user     (config/config-str :mb-db-user)
+                    :password (config/config-str :mb-db-pass)}))))
 
 (defn jdbc-details
   "Takes our own MB details map and formats them properly for connection details for JDBC."

test/metabase/sync/analyze/fingerprint/insights_test.clj

 (ns metabase.sync.analyze.fingerprint.insights-test
   (:require [expectations :refer :all]
-            [metabase.sync.analyze.fingerprint.insights :refer :all :as i]))
+            [metabase.sync.analyze.fingerprint.insights :as i :refer :all]))
 
 (def ^:private cols [{:base_type :type/DateTime} {:base_type :type/Number}])