add docs for --watch flag on :dev-start alias

- A path object cannot be printed via warnf and %s.
- Some paths from all-paths-to-watch were causing beholder to choke

deps.edn

@@ -247,11 +247,13 @@
     com.clojure-goes-fast/clj-memory-meter
     {:mvn/version "0.4.0"}                     ; Enables easy memory measurement
     com.gfredericks/test.chuck   {:mvn/version "0.2.15"}                    ; generating strings from regexes (useful with malli)
+    com.nextjournal/beholder     {:mvn/version "1.0.2"}                     ; watcher
     criterium/criterium          {:mvn/version "0.4.6"}                     ; benchmarking library
     dev.weavejester/hashp        {:mvn/version "0.4.0"}                     ; debugging/spying utility
     djblue/portal                {:mvn/version "0.59.0"}                    ; ui for inspecting values
-    io.github.camsaul/humane-are {:mvn/version "1.0.2"}
-    io.github.metabase/hawk      {:mvn/version "1.0.7"}
+    io.github.camsaul/humane-are {:mvn/version "1.0.2"}                     ; cleaner test output
+    io.github.metabase/hawk      {:mvn/version "1.0.7"}                     ; test runner
+    io.github.tonsky/clj-reload  {:mvn/version "0.9.5"}                     ; reloader
     jonase/eastwood              {:mvn/version "1.4.3"                      ; inspects namespaces and reports possible problems using tools.analyzer
                                   :exclusions
                                   [org.ow2.asm/asm-all]}
@@ -306,6 +308,9 @@
   ;; 1. Runs (dev) (start!) for you
   ;; 2. This starts the repl too: just like the :nrepl alias below. (see [[user/-main]])
   ;; clj -M:dev:dev-start:drivers:drivers-dev:ee:ee-dev
+  ;;
+  ;; To start it with hot code reloading, use:
+  ;; clj -M:dev:dev-start:drivers:drivers-dev:ee:ee-dev --watch
   :dev-start {:main-opts ["-m" "user"]
               :jvm-opts ["-Dmb.run.mode=dev"
                          "-Dmacaw.run.mode=dev"
@@ -868,13 +873,6 @@
   :test/kondo
   {:exec-args {:only [".clj-kondo/test"]}}
 
-  ;; watch and reload clojure namespaces
-  :watch {:extra-deps
-          {com.nextjournal/beholder     {:mvn/version "1.0.2"} ;; watcher
-           io.github.tonsky/clj-reload {:mvn/version "0.9.5"}} ;; reloader
-          :extra-paths "dev/src/watch"
-          :main-opts ["-m" "watch.watcher"]}
-
   ;; DB configs -- start DBs with:
 
   ;; ./bin/mage start-db postgres oldest

dev/src/user.clj

@@ -51,11 +51,19 @@
   (in-ns 'dev)
   :loaded)
 
+(defn watch? []
+  (contains? (set *command-line-args*) "--watch"))
+
 (defn -main
   "This is called by the `:dev-start` cli alias.
 
-  Try it out: `clj -M:dev:dev-start:drivers:drivers-dev:ee:ee-dev`"
+  Try it out: `clj -M:dev:dev-start:drivers:drivers-dev:ee:ee-dev`
+
+  Command line options:
+   - `--watch` - start the hot-reload clojure code watcher"
   [& _args]
   (future (nrepl.cmdline/-main "-p" "50605" "-b" "0.0.0.0"))
+  (when (watch?)
+    (future (requiring-resolve 'watch.watcher/watcher)))
   ((requiring-resolve 'dev/start!))
   (deref (promise)))

dev/src/watch/watcher.clj

@@ -1,51 +1,29 @@
-(ns watch.watcher
-  (:require [clj-reload.core :as reload]
-            [clojure.edn :as edn]
-            [clojure.string :as str]
-            [dev :as dev]
-            [metabase.util.log :as log]
-            [nextjournal.beholder :as beholder]
-            [user :as user])
+(ns ^:clj-reload/no-unload
+ ^:clj-reload/no-reload
+ watch.watcher
+  (:require
+   [clj-reload.core :as reload]
+   [dev :as dev]
+   [metabase.util.log :as log]
+   [nextjournal.beholder :as beholder]
+   [user :as user])
   (:gen-class))
 
 (set! *warn-on-reflection* true)
 
-(def all-paths-to-watch
-  "Returns all paths that contain code. These are the paths we should watch."
-  (memoize
-   (fn all-paths-to-watch* []
-     (->> (str (System/getProperty "user.dir") "/deps.edn")
-          slurp
-          edn/read-string
-          :aliases
-          vals
-          (keep :extra-paths)
-          (mapv #(if (coll? %) % [%]))
-          (apply concat)
-          (map (comp first #(str/split % #"/")))
-          (concat ["dev" "src" "test"])
-          distinct
-          vec))))
-
 (defn watch-fn
   "Reloads the system when a file changes."
-  [{:keys [type path]}]
-  (log/warnf "type: %s | path: %s" type path)
-  (let [before (System/currentTimeMillis)
-        _ (log/warn
-           (-> (reload/reload {:throw false
-                               :no-reload '#{watch.watcher user dev}})
-               (update :unloaded count)
-               (update :loaded count)))
-        after (System/currentTimeMillis)
-        _ (log/warn (str "Reloaded in " (- after before) " ms"))]))
+  [change]
+  (log/warn "Change detected. Reloading system. " (pr-str change) " ...")
+  (reload/reload {:throw :false}))
+
+(def ^:private paths
+  ["src" "test" "enterprise/backend" "modules"])
 
-#_:clj-kondo/ignore
 (defonce watcher
   (do
-    (log/warn "Watching paths:" (all-paths-to-watch))
-    (reload/init {:dirs (all-paths-to-watch)})
-    (apply (partial beholder/watch watch-fn) (all-paths-to-watch))))
+    (log/warn "Watching paths:" paths)
+    (apply beholder/watch watch-fn paths)))
 
 (defn -main "Watcher main function"
   [& _args]
@@ -54,6 +32,6 @@
 
 (comment
 
-  (beholder/stop watcher)
+  (reload/reload)
 
-  )
+  (beholder/stop watcher))

mage/mage/be_dev.clj

@@ -45,7 +45,12 @@
   "Evaluate Clojure code in a running nREPL server. With one arg, reads port from .nrepl-port file.
    With two args, uses the provided port number. Returns and formats the evaluation results."
   ([nns code]
-   (nrepl-eval (or nns "user") code (slurp ".nrepl-port")))
+   (nrepl-eval (or nns "user") code (try (slurp ".nrepl-port")
+                                         (catch Exception _
+                                           (throw (ex-info
+                                                   (str
+                                                    "Unable to find .nrepl-port, is the server's repl running?"
+                                                    " See: the :dev-start alias in deps.edn") {}))))))
   ([nns code port]
    (try (let [port (safe-parse-int port)
               s (java.net.Socket. "localhost" port)
@@ -94,6 +99,11 @@
 
   (nrepl-eval "metabase.logger-test" "(do (println :!! hi) hi)" 59498)
 
-  (nrepl-eval "metabase.logger-test" "*ns*" 59498)
+  (nrepl-eval "metabase.logger-test" "*ns*")
+
+  (nrepl-eval "dev.migrate" "(do (rollback! :count 1) ::rollback-done)")
+  (nrepl-eval "dev.migrate" "(do (migrate! :up) ::migrate-up-done)")
+
+  (nrepl-eval "")
 
   (println code-str))