Add use-beholder component, deprecate use-hawk

deps.edn

@@ -2,10 +2,10 @@
         buddy/buddy-sign               {:mvn/version "3.4.333"}
         cider/cider-nrepl              {:mvn/version "0.28.2"}
         clj-http/clj-http              {:mvn/version "3.12.3"}
+        com.nextjournal/beholder       {:mvn/version "1.0.0"}
         com.xtdb/xtdb-core             {:mvn/version "1.21.0-beta2"}
         com.xtdb/xtdb-jdbc             {:mvn/version "1.21.0-beta2"}
         com.xtdb/xtdb-rocksdb          {:mvn/version "1.21.0-beta2"}
-        hawk/hawk                      {:mvn/version "0.2.11"}
         info.sunng/ring-jetty9-adapter {:mvn/version "0.17.2"}
         jarohen/chime                  {:mvn/version "0.3.3"}
         lambdaisland/uri               {:mvn/version "1.13.95"}
@@ -18,7 +18,9 @@
         org.postgresql/postgresql      {:mvn/version "42.3.2"}
         ring/ring-defaults             {:mvn/version "0.3.3"}
         rum/rum                        {:mvn/version "0.12.8"
-                                        :exclusions [cljsjs/react cljsjs/react-dom]}}
+                                        :exclusions [cljsjs/react cljsjs/react-dom]}
+        ;; deprecated
+        hawk/hawk                      {:mvn/version "0.2.11"}}
  :aliases {:dev {:extra-deps {org.slf4j/slf4j-simple {:mvn/version "2.0.0-alpha5"}}
                  :main-opts ["-m" "nrepl.cmdline"]}
            :format {:extra-deps {cljfmt/cljfmt {:mvn/version "0.8.2"}}

src/com/biffweb.clj

@@ -1,5 +1,6 @@
 (ns com.biffweb
-  (:require [clojure.string :as str]
+  (:require [clojure.stacktrace :as st]
+            [clojure.string :as str]
             [com.biffweb.impl.middleware :as middle]
             [com.biffweb.impl.misc :as misc]
             [com.biffweb.impl.rum :as brum]
@@ -131,6 +132,14 @@
   [& body]
   `(try ~@body (catch Exception ~'_ nil)))
 
+(defmacro catchall-verbose
+  [& body]
+  "Like catchall, but prints exceptions."
+  `(try
+    ~@body
+    (catch Exception e#
+      (st/print-stack-trace e#))))
+
 (defmacro letd
   "Like let, but transparently wraps all bindings with delay.
 
@@ -177,20 +186,30 @@
 ;;;; misc
 
 (defn use-hawk
-  "A Biff component that runs code when files are changed, via Hawk.
+  "Deprecated. Use use-beholder instead.
+
+  use-beholder is a drop-in replacement for use-hawk, except that keys must be
+  prefixed with :biff.beholder/ instead of :biff.hawk/"
+  [{:biff.hawk/keys [on-save exts paths]
+    :or {paths ["src" "resources"]}
+    :as sys}]
+  (misc/use-hawk sys))
+
+(defn use-beholder
+  "A Biff component that runs code when files are changed, via Beholder.
 
-  See (https://github.com/wkf/hawk).
+  See https://github.com/nextjournal/beholder.
 
   on-save:  A single-argument function to call whenever a file is saved.
-            Receives the system map as a parameter. The function is called no
-            more than once every 500 milliseconds.
+            Receives the system map as a parameter. Subsequent file saves
+            that occur within one second are ignored.
   paths:    A collection of root directories to monitor for file changes.
   exts:     If exts is non-empty, files that don't end in one of the extensions
             will be ignored."
-  [{:biff.hawk/keys [on-save exts paths]
+  [{:biff.beholder/keys [on-save exts paths]
     :or {paths ["src" "resources"]}
     :as sys}]
-  (misc/use-hawk sys))
+  (misc/use-beholder sys))
 
 (defn reitit-handler
   "Convenience wrapper for reitit.ring/ring-handler.

src/com/biffweb/impl/misc.clj

@@ -3,14 +3,35 @@
             [buddy.sign.jwt :as jwt]
             [chime.core :as chime]
             [clj-http.client :as http]
+            [clojure.stacktrace :as st]
             [clojure.string :as str]
             [clojure.tools.logging :as log]
             [com.biffweb.impl.time :as time]
             [com.biffweb.impl.util :as util]
             [hawk.core :as hawk]
+            [nextjournal.beholder :as beholder]
             [reitit.ring :as reitit-ring]
             [ring.adapter.jetty9 :as jetty]))
 
+(defn use-beholder [{:biff.beholder/keys [on-save exts paths]
+                     :or {paths ["src" "resources"]}
+                     :as sys}]
+  (let [;; Poor man's debouncer -- don't want to pull in core.async just for
+        ;; this, and don't want to spend time figuring out how else to do it.
+        last-called (atom #inst "1970")
+        watch (apply beholder/watch
+                     (fn [{:keys [path]}]
+                       (when (and (or (empty? exts)
+                                      (some #(str/ends-with? path %) exts))
+                                  (time/elapsed? @last-called :now 1 :seconds))
+                         ;; Give all the files some time to get written before invoking the callback.
+                         (Thread/sleep 100)
+                         (util/catchall-verbose (on-save sys))
+                         (reset! last-called (java.util.Date.))))
+                     paths)]
+    (update sys :biff/stop conj #(beholder/stop watch))))
+
+;; Deprecated
 (defn use-hawk [{:biff.hawk/keys [on-save exts paths]
                  :or {paths ["src" "resources"]}
                  :as sys}]

src/com/biffweb/impl/util.clj

@@ -3,11 +3,19 @@
             [clojure.java.shell :as shell]
             [clojure.pprint :as pp]
             [clojure.spec.alpha :as spec]
+            [clojure.stacktrace :as st]
             [clojure.string :as str]
             [clojure.tools.logging :refer [info]]
             [clojure.tools.namespace.repl :as tn-repl]
             [clojure.walk :as walk]))
 
+(defmacro catchall-verbose
+  [& body]
+  `(try
+    ~@body
+    (catch Exception e#
+      (st/print-stack-trace e#))))
+
 (defn start-system [system-atom init]
   (reset! system-atom (merge {:biff/stop '()} init))
   (loop [{[f & components] :biff/components :as sys} init]