RE: SmtpAppender not working

Baron Schwartz 7 Apr 2005 00:47:24 -0000

Yes, there is much to criticize about that architecture. I'm not sure if anything else needs to load System.Web.dll, but that's kind of a monster DLL to load, too. I'm also wondering if there's much need for passing through the credentials of the process, for environments that support that. I know it's not a really big deal to have the conditionally compiled code, but that's not compatible across platforms; just one more thing to think about. I'd hate to get into saving and restoring the SMTP value. That would be a tough bug to track down in a multi-threaded situation, blegh.

Well, I'm not a super socket programmer, and not the best at architecting this kind of stuff, but I'd be willing to give it a shot if anyone else thinks it's worth doing. I don't want to do something that isn't welcome or useful, though.

Baron

--
"I am as bad as the worst, but, thank God, I am as good as the best."
    - Walt Whitman

On Thu, 7 Apr 2005, Nicko Cadell wrote:

I agree that the .NET API is not great with regard to the
SmtpMail.SmtpServer. I would have preferred it if the server could have
been passed on a per message basis. Also why did they choose to deliver
mail functionality in the System.Web assembly?

We could change the appender to store the current SmtpMail.SmtpServer
value, set the configured server before sending the mail, and then
restore the previous value. That would probably reduce the impact down
to 0.1% but make it even harder to track down!

Nicko

-----Original Message-----
From: Baron Schwartz [mailto:[EMAIL PROTECTED]
Sent: 06 April 2005 20:47
To: Log4NET User
Subject: RE: SmtpAppender not working

Right - sorry, I didn't word that very well.  You know what I
mean, but in case others don't, here is the source code in
src/Appender/SmtpAppender.cs:

280 :                   MailMessage mailMessage = new
MailMessage();
281 :                   mailMessage.Body = writer.ToString();
282 :                   mailMessage.From = m_from;
283 :                   mailMessage.To = m_to;
284 :                   mailMessage.Subject = m_subject;

... and further on,

334 :                   if (m_smtpHost != null &&
m_smtpHost.Length > 0)
335 :                   {
336 :                   SmtpMail.SmtpServer = m_smtpHost;
337 :                   }
338 :
339 :                   SmtpMail.Send(mailMessage);

Personally, I don't like bugs that only occur 1% of the time.
 They are the hardest to track down and reproduce.

Baron

--
"I am as bad as the worst, but, thank God, I am as good as the best."
     - Walt Whitman

On Wed, 6 Apr 2005 [EMAIL PROTECTED] wrote:

SmtpServer is a static property of the SmtpMail class, but

MailMessage

is an object - unique for each message.

I guess you might care which mail server you send the message from,
but I can't see why it would matter for 99% of the cases.

-----Original Message-----
From: Baron Schwartz [mailto:[EMAIL PROTECTED]
Sent: Wednesday, April 06, 2005 12:24 PM
To: Log4NET User
Subject: RE: SmtpAppender not working

I agreed with you until I just thought of something:

MailMessage uses

static properties to set the SMTP server etc. Tell me if

I'm wrong,

but that affects anything that's using MailMessage, on a

per-process basis.

So, if my system is using MailMessage to send email, and I set my
message up and get it ready to send but then make a call to logging
functionality before actually sending the mail, it might go

through a

different SMTP server than I intended, right?

I'm not sure if this is a big problem, but it could be a subtle one.
And multi-threading issues could come into play too.  That

could get

tough to debug.

Baron

--
"I am as bad as the worst, but, thank God, I am as good as

the best."

    - Walt Whitman
On Sat, 2 Apr 2005, Nicko Cadell wrote:
Baron,
The runtime provides SMTP support through the MailMessage.

Microsoft

have chosen to implement it using their CDO library. Usually CDO
works

fine, however it is possible for it to be disabled.

While it should be simple to implement a system that sends mail
directly via port 25 I'm not sure it this is necessarily

the best use

of resources as CDO works out of the box.

If someone wants to look at doing this it may be best to make the
mail

sending functionality of the SmtpAppender pluggable between the
current MailMessage and an independent implementation.

Nicko

-----Original Message-----
From: Baron Schwartz [mailto:[EMAIL PROTECTED]
Sent: 24 March 2005 14:27
To: Log4NET User
Subject: RE: SmtpAppender not working

Thanks Nicko.

I have searched more on the various error messages and found that
indeed it is a problem with CDO on my laptop.  When I

configure the

logging on the production machines, it works fine. I'm

not familiar

with what CDO is or how/why it's not working on my laptop, other
than
maybe I borked it up when I turned off every

non-essential service

(I

believe the Systems staff has all sorts of stuff running on the
production servers... not my job).

I did try using the fully qualified name of the SMTP machine, and
even its IP address; like I said I've had no problems

with sending

to

that machine with the SMTP software I've written (telnet, too).

I looked through the source code for the SmtpAppender more.
I'm not sure how many people would use the more advanced

settings,

such as sending through the credentials of the process

under which

log4net runs -- and I know it's bad to reinvent the wheel.  But,
just

to play devil's advocate, is there any justification for an SMTP
appender which sends via plain SMTP, without relying on
System.Web.Mail?  SMTP is trivial to implement, and this

might ease

the problems, and may even be more efficient as an

appender. I saw

a

lot of griping on the Internet about this CDO issue, with no real
resolutions.  It sounds like there may be some

Microsoftish "extend

the standard" issues with CDO. But I'm no expert on it,

as I said.

Baron
On Thu, 24 Mar 2005, Nicko Cadell wrote:
  "The transport failed to connect to the server"
It looks like the CDO implementation on the machine cannot
access the
mail server.
You config is fine for accessing an unauthenticated mail relay.
Can you try telneting directly into your mail server

from the box

running your app:
  telnet madrid 25
Type in "HELO" the server should respond with some

helpful message.

Type "QUIT" to exit. Does this work?
Have you tried specifying the smtpHost as a fully qualified
domain name?
or as an IP address? It may be that the CDO library cannot
resolve the
name.
Are you running any local firewall software that may be blocking
outbound connections, for some or all users or applications?
There seems to be several other people having the same

problem with

various fixes discussed here:

http://www.google.co.uk/search?q=transport+failed+to+connect+to+the+

s
e
rv
er+CDO
Nicko
-----Original Message-----
From: Baron Schwartz [mailto:[EMAIL PROTECTED]
Sent: 21 March 2005 16:57
To: [email protected]
Subject: SmtpAppender not working
Hi,
I've searched the web and read the manual and some of the
code, but
feel free to point me somewhere there's an answer... I

can't find

much on this.
My SmtpAppender isn't able to connect to the smtpHost.  I'm on
Windows using MS framework v1.1.  Here's my config file
([EMAIL PROTECTED]
is bogus -- I'm using a real value), test code, and the

error I'm

getting in the console window when the log fails to
email. The SMTP
server, madrid, is an open relay inside our firewall,
which requires
no authentication or anything.
I send mail with it from a bunch of other apps.
One thing I did notice, is that apparently there are some other
parameters I could be putting in the config file, but I'm
not sure
what they should be (the example config seems to be incomplete).
Starting at SmtpAppender.cs, and looking at its
properties, it looks
like username, password etc *could* be put in the

config file. I

didn't read through enough of the code to determine what the
parameters would be named, because they wouldn't be

necessary for

this application, but if someone points me to how I can

find it out

(short of stepping through the code) I'm happy to update the
example, or augment it with a more complete example.

Thanks for any help.

--- Snip ---
<?xml version="1.0" encoding="utf-8" ?> <configuration>
    <configSections>
        <section name="log4net"
type="log4net.Config.Log4NetConfigurationSectionHandler,

log4net" />

    </configSections>
    <log4net>
        <appender name="SmtpAppender"
type="log4net.Appender.SmtpAppender">
            <to value="[EMAIL PROTECTED]" />
            <from value="[EMAIL PROTECTED]" />
            <subject value="Baaaaad error" />
            <smtpHost value="madrid" />
            <bufferSize value="4" />
            <lossy value="true" />
            <evaluator type="log4net.Core.LevelEvaluator">
                <threshold value="WARN"/>
            </evaluator>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%-5p %-20t %d

%c line %L%n

%m%n" />
            </layout>
        </appender>
        <root>
            <appender-ref ref="SmtpAppender" />
        </root>
    </log4net>
    <appSettings>
    </appSettings>
</configuration>
--- Snip ---
using System;
using log4net;
using log4net.Config;
namespace TestHarness {
    public class TestHarness {
        static readonly ILog log =
LogManager.GetLogger(typeof(TestHarness));
        public static void Main(string[] args) {
            XmlConfigurator.Configure();
            log.Warn("hey, this is an error!");
        }
    }
}
--- Snip ---
log4net:ERROR [SmtpAppender] Error occurred while

sending e-mail

notification.
System.Web.HttpException: Could not access 'CDO.Message'
object. ---> System.Ref
lection.TargetInvocationException: Exception has been

thrown by the

target of an  invocation. --->
System.Runtime.InteropServices.COMException
(0x80040213): The
transport failed to connect to the server.

   --- End of inner exception stack trace ---
   at System.RuntimeType.InvokeDispMethod(String name,

BindingFlags

invokeAttr, Object target, Object[] args, Boolean[]

byrefModifiers,

Int32 culture, String[]
namedParameters)
   at System.RuntimeType.InvokeMember(String name, BindingFlags
invokeAttr, Bind er binder, Object target, Object[] args,
ParameterModifier[] modifiers, CultureI nfo culture, String[]
namedParameters)
   at System.Type.InvokeMember(String name, BindingFlags

invokeAttr,

Binder bind er, Object target, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(Type
type, Object obj, St ring methodName, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(Object
obj, String method Name, Object[] args)
   --- End of inner exception stack trace ---
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(Object
obj, String method Name, Object[] args)
   at System.Web.Mail.CdoSysHelper.Send(MailMessage message)
   at System.Web.Mail.SmtpMail.Send(MailMessage message)
   at log4net.Appender.SmtpAppender.SendBuffer(LoggingEvent[]
events)

RE: SmtpAppender not working

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