backups: email the administrator when there's a problem

Refactor by moving the email-the-admin code out of the status checks and into a new separate tool.

This is why I suppressed non-error output of the backups last commit - so it doesn't send a daily email.

CHANGELOG.md

@@ -12,6 +12,10 @@ Control Panel:
 
 * Report free memory usage.
 
+System:
+
+* The daily backup will now email the administrator if there is a problem.
+
 v0.15 (January 1, 2016)
 -----------------------
 

management/daily_tasks.sh

@@ -2,7 +2,7 @@
 # This script is run daily (at 3am each night).
 
 # Take a backup.
-management/backup.py
+management/backup.py | management/email_administrator.py "Backup Status"
 
 # Run status checks and email the administrator if anything changed.
-management/status_checks.py --show-changes --smtp
+management/status_checks.py --show-changes | management/email_administrator.py "Status Checks Change Notice"

management/email_administrator.py

+#!/usr/bin/python3
+
+# Reads in STDIN. If the stream is not empty, mail it to the system administrator.
+
+import sys
+
+import smtplib
+from email.message import Message
+
+from utils import load_environment
+
+# Load system environment info.
+env = load_environment()
+
+# Process command line args.
+subject = sys.argv[1]
+
+# Administrator's email address.
+admin_addr = "administrator@" + env['PRIMARY_HOSTNAME']
+
+# Read in STDIN.
+content = sys.stdin.read().strip()
+
+# If there's nothing coming in, just exit.
+if content == "":
+	sys.exit(0)
+
+# create MIME message
+msg = Message()
+msg['From'] = "\"%s\" <%s>" % (env['PRIMARY_HOSTNAME'], admin_addr)
+msg['To'] = admin_addr
+msg['Subject'] = "[%s] %s" % (env['PRIMARY_HOSTNAME'], subject)
+msg.set_payload(content, "UTF-8")
+
+# send
+smtpclient = smtplib.SMTP('localhost', 25)
+smtpclient.ehlo()
+smtpclient.sendmail(
+        admin_addr, # MAIL FROM
+        admin_addr, # RCPT TO
+        msg.as_string())
+smtpclient.quit()

management/status_checks.py

@@ -767,15 +767,11 @@ def check_miab_version(env, output):
 			output.print_error("A new version of Mail-in-a-Box is available. You are running version %s. The latest version is %s. For upgrade instructions, see https://mailinabox.email. "
 				% (this_ver, latest_ver))
 
-def run_and_output_changes(env, pool, send_via_email):
+def run_and_output_changes(env, pool):
 	import json
 	from difflib import SequenceMatcher
 
-	if not send_via_email:
-		out = ConsoleOutput()
-	else:
-		import io
-		out = FileOutput(io.StringIO(""), 70)
+	out = ConsoleOutput()
 
 	# Run status checks.
 	cur = BufferedOutput()
@@ -834,28 +830,6 @@ def run_and_output_changes(env, pool, send_via_email):
 				out.add_heading(category)
 				out.print_warning("This section was removed.")
 
-	if send_via_email:
-		# If there were changes, send off an email.
-		buf = out.buf.getvalue()
-		if len(buf) > 0:
-			# create MIME message
-			from email.message import Message
-			msg = Message()
-			msg['From'] = "\"%s\" <administrator@%s>" % (env['PRIMARY_HOSTNAME'], env['PRIMARY_HOSTNAME'])
-			msg['To'] = "administrator@%s" % env['PRIMARY_HOSTNAME']
-			msg['Subject'] = "[%s] Status Checks Change Notice" % env['PRIMARY_HOSTNAME']
-			msg.set_payload(buf, "UTF-8")
-
-			# send to administrator@
-			import smtplib
-			mailserver = smtplib.SMTP('localhost', 25)
-			mailserver.ehlo()
-			mailserver.sendmail(
-				"administrator@%s" % env['PRIMARY_HOSTNAME'], # MAIL FROM
-				"administrator@%s" % env['PRIMARY_HOSTNAME'], # RCPT TO
-				msg.as_string())
-			mailserver.quit()
-
 	# Store the current status checks output for next time.
 	os.makedirs(os.path.dirname(cache_fn), exist_ok=True)
 	with open(cache_fn, "w") as f:
@@ -886,7 +860,7 @@ class FileOutput:
 		words = re.split("(\s+)", message)
 		linelen = 0
 		for w in words:
-			if linelen + len(w) > self.width-1-len(first_line):
+			if self.width and (linelen + len(w) > self.width-1-len(first_line)):
 				print(file=self.buf)
 				print("   ", end="", file=self.buf)
 				linelen = 0
@@ -902,10 +876,22 @@ class FileOutput:
 class ConsoleOutput(FileOutput):
 	def __init__(self):
 		self.buf = sys.stdout
-		try:
-			self.width = int(shell('check_output', ['stty', 'size']).split()[1])
-		except:
-			self.width = 76
+		
+		# Do nice line-wrapping according to the size of the terminal.
+		# The 'stty' program queries standard input for terminal information.
+		if sys.stdin.isatty():
+			try:
+				self.width = int(shell('check_output', ['stty', 'size']).split()[1])
+			except:
+				self.width = 76
+
+		else:
+			# However if standard input is not a terminal, we would get
+			# "stty: standard input: Inappropriate ioctl for device". So
+			# we test with sys.stdin.isatty first, and if it is not a
+			# terminal don't do any line wrapping. When this script is
+			# run from cron, or if stdin has been redirected, this happens.
+			self.width = None
 
 class BufferedOutput:
 	# Record all of the instance method calls so we can play them back later.
@@ -933,7 +919,7 @@ if __name__ == "__main__":
 		run_checks(False, env, ConsoleOutput(), pool)
 
 	elif sys.argv[1] == "--show-changes":
-		run_and_output_changes(env, pool, sys.argv[-1] == "--smtp")
+		run_and_output_changes(env, pool)
 
 	elif sys.argv[1] == "--check-primary-hostname":
 		# See if the primary hostname appears resolvable and has a signed certificate.