service: add basic cron support

Library/Homebrew/service.rb

@@ -145,10 +145,8 @@ module Homebrew
       case T.unsafe(value)
       when nil
         @run_type
-      when :immediate, :interval
+      when :immediate, :interval, :cron
         @run_type = value
-      when :cron
-        raise TypeError, "Service#run_type does not support cron"
       when Symbol
         raise TypeError, "Service#run_type allows: '#{RUN_TYPE_IMMEDIATE}'/'#{RUN_TYPE_INTERVAL}'/'#{RUN_TYPE_CRON}'"
       else
@@ -168,6 +166,64 @@ module Homebrew
       end
     end
 
+    sig { params(value: T.nilable(String)).returns(T.nilable(Hash)) }
+    def cron(value = nil)
+      case T.unsafe(value)
+      when nil
+        @cron
+      when String
+        @cron = parse_cron(T.must(value))
+      else
+        raise TypeError, "Service#cron expects a String"
+      end
+    end
+
+    sig { returns(T::Hash[Symbol, T.any(Integer, String)]) }
+    def default_cron_values
+      {
+        Month:   "*",
+        Day:     "*",
+        Weekday: "*",
+        Hour:    "*",
+        Minute:  "*",
+      }
+    end
+
+    sig { params(cron_statement: String).returns(T::Hash[Symbol, T.any(Integer, String)]) }
+    def parse_cron(cron_statement)
+      parsed = default_cron_values
+
+      case cron_statement
+      when "@hourly"
+        parsed[:Minute] = 0
+      when "@daily"
+        parsed[:Minute] = 0
+        parsed[:Hour] = 0
+      when "@weekly"
+        parsed[:Minute] = 0
+        parsed[:Hour] = 0
+        parsed[:Weekday] = 0
+      when "@monthly"
+        parsed[:Minute] = 0
+        parsed[:Hour] = 0
+        parsed[:Day] = 1
+      when "@yearly", "@annually"
+        parsed[:Minute] = 0
+        parsed[:Hour] = 0
+        parsed[:Day] = 1
+        parsed[:Month] = 1
+      else
+        cron_parts = cron_statement.split
+        raise TypeError, "Service#parse_cron expects a valid cron syntax" if cron_parts.length != 5
+
+        [:Minute, :Hour, :Day, :Month, :Weekday].each_with_index do |selector, index|
+          parsed[selector] = Integer(cron_parts.fetch(index)) if cron_parts.fetch(index) != "*"
+        end
+      end
+
+      parsed
+    end
+
     sig { params(variables: T::Hash[String, String]).returns(T.nilable(T::Hash[String, String])) }
     def environment_variables(variables = {})
       case T.unsafe(variables)
@@ -246,6 +302,10 @@ module Homebrew
       base[:StandardErrorPath] = @error_log_path if @error_log_path.present?
       base[:EnvironmentVariables] = @environment_variables unless @environment_variables.empty?
 
+      if @cron.present? && @run_type == RUN_TYPE_CRON
+        base[:StartCalendarInterval] = @cron.reject { |_, value| value == "*" }
+      end
+
       base.to_plist
     end
 
@@ -295,9 +355,15 @@ module Homebrew
 
       instance_eval(&@service_block)
       options = []
-      options << "Persistent=true=" if @run_type == RUN_TYPE_CRON
+      options << "Persistent=true" if @run_type == RUN_TYPE_CRON
       options << "OnUnitActiveSec=#{@interval}" if @run_type == RUN_TYPE_INTERVAL
 
+      if @run_type == RUN_TYPE_CRON
+        minutes = @cron[:Minute] == "*" ? "*" : format("%02d", @cron[:Minute])
+        hours   = @cron[:Hour] == "*" ? "*" : format("%02d", @cron[:Hour])
+        options << "OnCalendar=#{@cron[:Weekday]}-*-#{@cron[:Month]}-#{@cron[:Day]} #{hours}:#{minutes}:00"
+      end
+
       timer + options.join("\n")
     end
   end

Library/Homebrew/test/service_spec.rb

@@ -32,16 +32,20 @@ describe Homebrew::Service do
     end
   end
 
-  describe "#run_type" do
+  describe "#process_type" do
-    it "throws for cron type" do
+    it "throws for unexpected type" do
       f.class.service do
         run opt_bin/"beanstalkd"
-        run_type :cron
+        process_type :cow
       end
 
-      expect { f.service.manual_command }.to raise_error TypeError, "Service#run_type does not support cron"
+      expect {
+        f.service.manual_command
+      }.to raise_error TypeError, "Service#process_type allows: 'background'/'standard'/'interactive'/'adaptive'"
     end
+  end
 
+  describe "#run_type" do
     it "throws for unexpected type" do
       f.class.service do
         run opt_bin/"beanstalkd"
@@ -206,6 +210,40 @@ describe Homebrew::Service do
       EOS
       expect(plist).to eq(plist_expect)
     end
+
+    it "returns valid cron plist" do
+      f.class.service do
+        run opt_bin/"beanstalkd"
+        run_type :cron
+        cron "@daily"
+      end
+
+      plist = f.service.to_plist
+      plist_expect = <<~EOS
+        <?xml version="1.0" encoding="UTF-8"?>
+        <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+        <plist version="1.0">
+        <dict>
+        \t<key>Label</key>
+        \t<string>homebrew.mxcl.formula_name</string>
+        \t<key>ProgramArguments</key>
+        \t<array>
+        \t\t<string>#{HOMEBREW_PREFIX}/opt/formula_name/bin/beanstalkd</string>
+        \t</array>
+        \t<key>RunAtLoad</key>
+        \t<false/>
+        \t<key>StartCalendarInterval</key>
+        \t<dict>
+        \t\t<key>Hour</key>
+        \t\t<integer>0</integer>
+        \t\t<key>Minute</key>
+        \t\t<integer>0</integer>
+        \t</dict>
+        </dict>
+        </plist>
+      EOS
+      expect(plist).to eq(plist_expect)
+    end
   end
 
   describe "#to_systemd_unit" do
@@ -314,6 +352,53 @@ describe Homebrew::Service do
       EOS
       expect(unit).to eq(unit_expect)
     end
+
+    it "throws on incomplete cron" do
+      f.class.service do
+        run opt_bin/"beanstalkd"
+        run_type :cron
+        cron "1 2 3 4"
+      end
+
+      expect {
+        f.service.to_systemd_timer
+      }.to raise_error TypeError, "Service#parse_cron expects a valid cron syntax"
+    end
+
+    it "returns valid cron timers" do
+      styles = {
+        "@hourly":   "*-*-*-* *:00:00",
+        "@daily":    "*-*-*-* 00:00:00",
+        "@weekly":   "0-*-*-* 00:00:00",
+        "@monthly":  "*-*-*-1 00:00:00",
+        "@yearly":   "*-*-1-1 00:00:00",
+        "@annually": "*-*-1-1 00:00:00",
+        "5 5 5 5 5": "5-*-5-5 05:05:00",
+      }
+
+      styles.each do |cron, calendar|
+        f.class.service do
+          run opt_bin/"beanstalkd"
+          run_type :cron
+          cron cron.to_s
+        end
+
+        unit = f.service.to_systemd_timer
+        unit_expect = <<~EOS
+          [Unit]
+          Description=Homebrew generated timer for formula_name
+
+          [Install]
+          WantedBy=timers.target
+
+          [Timer]
+          Unit=homebrew.formula_name
+          Persistent=true
+          OnCalendar=#{calendar}
+        EOS
+        expect(unit).to eq(unit_expect.chomp)
+      end
+    end
   end
 
   describe "#timed?" do