fix: replication process detection

Author: hschne

lib/litestream.rb

@@ -90,54 +90,7 @@ def systemctl_command
     end
 
     def replicate_process
-      info = {}
-      if !`which systemctl`.empty?
-        systemctl_status = `#{Litestream.systemctl_command}`.chomp
-        # ["● litestream.service - Litestream",
-        #  "     Loaded: loaded (/lib/systemd/system/litestream.service; enabled; vendor preset: enabled)",
-        #  "     Active: active (running) since Tue 2023-07-25 13:49:43 UTC; 8 months 24 days ago",
-        #  "   Main PID: 1179656 (litestream)",
-        #  "      Tasks: 9 (limit: 1115)",
-        #  "     Memory: 22.9M",
-        #  "        CPU: 10h 49.843s",
-        #  "     CGroup: /system.slice/litestream.service",
-        #  "             └─1179656 /usr/bin/litestream replicate",
-        #  "",
-        #  "Warning: some journal files were not opened due to insufficient permissions."]
-        systemctl_status.split("\n").each do |line|
-          line.strip!
-          if line.start_with?("Main PID:")
-            _key, value = line.split(":")
-            pid, _name = value.strip.split(" ")
-            info[:pid] = pid
-          elsif line.start_with?("Active:")
-            value, _ago = line.split(";")
-            status, timestamp = value.split(" since ")
-            info[:started] = DateTime.strptime(timestamp.strip, "%a %Y-%m-%d %H:%M:%S %Z")
-            status_match = status.match(%r{\((?<status>.*)\)})
-            info[:status] = status_match ? status_match[:status] : nil
-          end
-        end
-      else
-        litestream_replicate_ps = `ps -ax | grep litestream | grep replicate`.chomp
-        litestream_replicate_ps.split("\n").each do |line|
-          next unless line.include?("litestream replicate")
-          pid, * = line.split(" ")
-          info[:pid] = pid
-          state, _, lstart = `ps -o "state,lstart" #{pid}`.chomp.split("\n").last.partition(/\s+/)
-
-          info[:status] = case state[0]
-          when "I" then "idle"
-          when "R" then "running"
-          when "S" then "sleeping"
-          when "T" then "stopped"
-          when "U" then "uninterruptible"
-          when "Z" then "zombie"
-          end
-          info[:started] = DateTime.strptime(lstart.strip, "%a %b %d %H:%M:%S %Y")
-        end
-      end
-      info
+      systemctl_info || process_info || {}
     end
 
     def databases
@@ -157,6 +110,70 @@ def databases
         end
       end
     end
+
+    private
+
+    def systemctl_info
+      return if `which systemctl`.empty?
+
+      systemctl_output = `#{Litestream.systemctl_command}`
+      systemctl_exit_code = $?.exitstatus
+      return unless systemctl_exit_code.zero?
+
+      # ["● litestream.service - Litestream",
+      #  "     Loaded: loaded (/lib/systemd/system/litestream.service; enabled; vendor preset: enabled)",
+      #  "     Active: active (running) since Tue 2023-07-25 13:49:43 UTC; 8 months 24 days ago",
+      #  "   Main PID: 1179656 (litestream)",
+      #  "      Tasks: 9 (limit: 1115)",
+      #  "     Memory: 22.9M",
+      #  "        CPU: 10h 49.843s",
+      #  "     CGroup: /system.slice/litestream.service",
+      #  "             └─1179656 /usr/bin/litestream replicate",
+      #  "",
+      #  "Warning: some journal files were not opened due to insufficient permissions."]
+
+      info = {}
+      systemctl_output.chomp.split("\n").each do |line|
+        line.strip!
+        if line.start_with?("Main PID:")
+          _key, value = line.split(":")
+          pid, _name = value.strip.split(" ")
+          info[:pid] = pid
+        elsif line.start_with?("Active:")
+          value, _ago = line.split(";")
+          status, timestamp = value.split(" since ")
+          info[:started] = DateTime.strptime(timestamp.strip, "%a %Y-%m-%d %H:%M:%S %Z")
+          status_match = status.match(%r{\((?<status>.*)\)})
+          info[:status] = status_match ? status_match[:status] : nil
+        end
+      end
+      info
+    end
+
+    def process_info
+      litestream_replicate_ps = `ps -ax | grep litestream | grep replicate`
+      systemctl_exit_code = $?.exitstatus
+      return unless systemctl_exit_code.zero?
+
+      info = {}
+      litestream_replicate_ps.chomp.split("\n").each do |line|
+        next unless line.include?("litestream replicate")
+        pid, * = line.split(" ")
+        info[:pid] = pid
+        state, _, lstart = `ps -o "state,lstart" #{pid}`.chomp.split("\n").last.partition(/\s+/)
+
+        info[:status] = case state[0]
+        when "I" then "idle"
+        when "R" then "running"
+        when "S" then "sleeping"
+        when "T" then "stopped"
+        when "U" then "uninterruptible"
+        when "Z" then "zombie"
+        end
+        info[:started] = DateTime.strptime(lstart.strip, "%a %b %d %H:%M:%S %Y")
+      end
+      info
+    end
   end
 end