Change error handling in CmdRunner to handle stderr errors

The training_db_sync script  does not break when errors are thrown while running commands with Ruby module Open3.

This edit changes the error handling in the script to check for errors present in stderr. This allows us to capture any such errors, and raise an exception if any are present. If errors are present in stderr while capturing data from source; copying data; or loading data to the destination, the script will delete sessions and tempfiles before exiting.

script/training_db_sync.rb

@@ -63,14 +63,26 @@ def capture_data_from_source
               --no-owner
     CMD
     Kernel.puts "Running pg_dump on #{source} ==> #{cmd}"
-    CmdRunner.run(cmd)
+    begin
+      CmdRunner.run(cmd)
+    rescue => e
+      clear_sessions
+      remove_temp_files
+      raise e
+    end
   end
 
   def copy_data_to_destination
     authenticate_to(destination)
     cmd = %(cat #{data_filename} | cf ssh beis-roda-#{destination} -c "cat > #{data_filename}")
     Kernel.puts "Copying data to #{destination} ==> #{cmd}"
-    CmdRunner.run(cmd)
+    begin
+      CmdRunner.run(cmd)
+    rescue => e
+      clear_sessions
+      remove_temp_files
+      raise e
+    end
   end
 
   def load_source_data_to_destination
@@ -80,7 +92,13 @@ def load_source_data_to_destination
           psql < #{data_filename}
     CMD
     Kernel.puts "Loading data from #{source} to #{destination} ==> #{cmd}"
-    CmdRunner.run(cmd)
+    begin
+      CmdRunner.run(cmd)
+    rescue => e
+      clear_sessions
+      remove_temp_files
+      raise e
+    end
   end
 
   def force_password_reset_for_users
@@ -138,13 +156,11 @@ class CmdRunner
     require "open3"
 
     def self.run(command)
-      begin
-        stdout, _stderr, _status = Open3.capture3(command)
-      rescue => error
-        raise "'#{command}' failed (#{error})"
-      end
+      _stdout, stderr, _status = Open3.capture3(command)
 
-      Kernel.puts stdout.chomp
+      if stderr
+        raise StandardError.new("Command: '#{command}' FAILED with error: '#{stderr}'")
+      end
     end
   end
 end