shorten deploy notification commit list

lib/tasks/hook.rake

@@ -1,4 +1,6 @@
-COMPARE_URL_API = "https://api.github.com/repos/Farmbot/Farmbot-Web-App/compare/"
+BASE_URL_API = "https://api.github.com/repos/Farmbot/Farmbot-Web-App/"
+COMPARE_URL_API = "#{BASE_URL_API}compare/"
+DEPLOYS_URL_API = "#{BASE_URL_API}deployments"
 COMPARE_URL_WEB = "https://github.com/Farmbot/Farmbot-Web-App/compare/"
 COMMIT_SHA = ENV["HEROKU_BUILD_COMMIT"]
 DESCRIPTION = ENV["HEROKU_BUILD_DESCRIPTION"]
@@ -8,24 +10,44 @@ def open_json(url)
   begin
     JSON.parse(URI.parse(url).open.read)
   rescue *[OpenURI::HTTPError, SocketError] => exception
-    puts exception.message
+    puts exception.message + ": #{url}"
     return {}
   end
 end
 
-def commit_messages
+def commits_since_main
   base_head = "main...#{COMMIT_SHA}"
   url = "#{COMPARE_URL_API}#{base_head}"
   data = open_json(url)
-  commits = data.fetch("commits", [])
-  web_url = "#{COMPARE_URL_WEB}#{base_head}"
+  data.fetch("commits", [])
+end
+
+def last_deploy_commit
+  data = open_json(DEPLOYS_URL_API)
+  (data[0] || {}).fetch("sha", nil)
+end
+
+def commits_since_last_deploy
+  last_sha_deployed = last_deploy_commit()
+  commits = []
+  commits_since_main.reverse.map do |commit|
+    if commit.fetch("sha") == last_sha_deployed
+      break
+    end
+    commits.push(commit["commit"]["message"].gsub("\n", " "))
+  end
+  commits
+end
+
+def details
   output = "\n\n"
   if !DESCRIPTION.nil?
     output += "#{DESCRIPTION}\n\n"
   end
-  output += "<#{web_url}|compare>\n"
-  messages = commits.map do |x|
-    output += "\n + #{x["commit"]["message"].gsub("\n", " ")}"
+  web_compare_url = "#{COMPARE_URL_WEB}#{COMMIT_SHA}...#{last_deploy_commit}"
+  output += "<#{web_compare_url}|compare>\n"
+  messages = commits_since_last_deploy.reverse.map do |commit|
+    output += "\n + #{commit}"
   end
   output
 end
@@ -35,7 +57,7 @@ namespace :hook do
   task release_info: :environment do
     if WEBHOOK_URL
       notification_text = "A new release has been deployed to the server."
-      info = notification_text + commit_messages
+      info = notification_text + details
       payload = {
         "mrkdwn": true,
         "text": notification_text,