Saturday, November 28, 2009

Terminating app due to uncaught exception 'NSInternalInconsistencyException'

One reason for getting this exception may be due to a typo in the name of the NIB file used to init an object.

In my case I was loading a view controller like so:


YellowViewController *yellowController = [[YellowViewController alloc] initWithNibName:@"YellowViev" bundle:nil];



whilst my bundle contained an YellowView.xib. I was using an "v" instead "w" in my NIB name.

So, yeah, check the names. XCode is pretty forgiving (and misleading) here. It would instantiate an object (from an non-existent NIB), in my case a view controller with a view member set to nil. Perhaps a better approach would be to return nil instead a half-baked, incorrect object. Instead it set me to a wild goose chase, to check the view outlet in the NIB and the ensuing scratching of the head.

The error message before the crash wasn't too helpful either:

ViewSwitcher[30112:20b] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UIViewController loadView] loaded the "YellowViev" nib but no view was set.'

Monday, November 09, 2009

Solving the (HY000/2002): Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' on Mac OS 10.5

I've been using the Apache version that comes pre-installed with the Leopard, and its companion installation of PHP, that can be enabled as described here. I figured that if Apple took the trouble to pre-install these, I'd better use them instead of re-installing them from scratch.

I also installed MySQL using the dmg package from mysql.com.

At this point PHP and MySQL seemed to be working fine on my system, each tried separately.

Things went ugly when I tried to call MySQL from within a PHP script. Calling $dbc = mysqli_connect(MSQL_HOST, MYSQL_USER, MYSQL_PASSWD, MYSQL_DB) yielded the HY000/2002 error, complaining about the inability to connect through /var/mysql/mysql.sock.

The docs for mysqli_connect indicate that if the host to connect to is the local host, the system will attempt to use a pipe instead of TCP/IP, perhaps for improved efficiency. So it looks like the /var/mysql/mysql.sock pipe is not present. A netstat -a | grep mysql indicates that that's indeed the case, instead there seems to be a /tmp/mysql.sock pipe on my system.

Nice, all I have to do is make use of that. A quick change to $dbc = mysqli_connect(MSQL_HOST, MYSQL_USER, MYSQL_PASSWD, MYSQL_DB, ini_get("mysqli.default_port"), '/tmp/mysql.sock') makes it work. Good times.

Not this is clearly a thing peculiar to my setup, I'd rather fix my setup instead of changing my code to work around this, especially since I need the code to be generic enough to run on a production server, with a different setup. So I take a look at the output provided by phpinfo. Here I see that MYSQL_SOCKET is /var/mysql/mysql.sock and mysqli.default_socket is not set. Then all I need to fix my system is to set mysqli.default_socket to '/tmp/mysql.sock'. To do that, I changed my /private/etc/php.ini to have the 'mysqli.default_socket =' line changed to 'mysqli.default_socket = /tmp/mysql.sock' and restart Apache (System Preferences -> Sharing -> Web Sharing disable and enable again).

Now my system is good to go, I can connect to MySQL from within PHP simply with $dbc = mysqli_connect(MSQL_HOST, MYSQL_USER, MYSQL_PASSWD, MYSQL_DB).

Note: The same issue may affect connecting through the regular mysql_connect, in which case you'll have to change your mysql.default_socket setting in a similar way.

Friday, September 18, 2009

Push To My Phone wins Judge's Choice Award in the 2009 Calling All Innovators Contest, presented by Forum Nokia

My latest project, Push To My Phone, has been awarded a prize in a competition I entered.

It's been an interesting experience, now having participated in 2 editions of the contest. I don't think I will enter in future editions, mainly because the way people at Nokia treat the participants. Basically if you're not one of the top price winners, who get monetary awards, you won't get much. As a Judge's Choice Award winner you're supposed to get a membership in their Launchpad program, though I'm still waiting on that. If you're one of the thousands of participants that don't get an award you don't get anything. No recognition at all, not even a thank you.

After the first edition I posted some feedback that was acknowledged, but promptly ignored in the second edition. Actually things went downhill, at least in my perception. I have more suggestions for improvement, but why bother.

I'm not sure what the goal of this contest is for Nokia, but I can tell you that they managed to alienate a few developers. If you look at the number of views on their discussion boards, in the threads related to the contest, you can see that the interest is waning from one edition to another.

There are way better opportunities out there.

Thursday, August 13, 2009

dynamically added web content in IE fails to display properly

If you're doing content modifications through DOM operations driven by JavaScript you must be aware that IE doesn't pick the CSS style dictated by the class name of the newly added elements.

So if you add an element like this:

<div id="test_id" class="test_class">example<div>

and your style comes from a CSS include like this:

<link rel="Stylesheet" href="css/default.css" type="text/css" media="screen,print" />

and you have styles corresponding to test_class (e.g. .test_class selector) in the externally included default.css file, they won't be applied.

This is a rather egregious issue, affecting only IE, that bit me several times.

One workaround is to use inline CSS, through the style attribute of the element. That seems to be working fine.

It'd be interesting to see if inline CSS in the <style> element gets picked up too. Also I wonder if the same issue is present for id selectors (e.g. #test_id selector).

Wednesday, July 29, 2009

Error when running Xcode sample projects

I've been through some sample code downloaded from the net and after opening a project and attempting to build it I was greeted with the following error:

"There is no SDK with specified name or path 'Unknown Path'". This is likely because those samples were built with a different version of the SDK than those I had installed.

A simple fix is to go to Project->Edit Project Settings, then go to "Base SDK for All Configurations" drop-down list and pick a version that you have installed on your system instead of the grayed (missing) one that's displayed.

Saturday, July 18, 2009

installing/upgrading Python + MySQLdb on Mac OS X

I've been working on a project that required the use of the urllib2.urlopen that takes a 3rd argument to indicate the guard timeout to break the blocking on an unresponsive socket. Alas this handy feature is only available in the versions of Python starting with 2.6. As Leopard comes with 2.5, I was faced with the prospect of upgrading to 2.6, hopefully without breaking existent functionality.

First step is to see where Python is installed by default:
which python
yields
/usr/bin/python
and
ls -l /usr/bin/python
yields
lrwxr-xr-x 1 root wheel 72 21 Feb 2008 /usr/bin/python -> ../../System/Library/Frameworks/Python.framework/Versions/2.5/bin/python

So there are the goodies. Good to know.


Next download Python for Mac from here.
Unpack and run
python setup.py build:
Traceback (most recent call last)
File "setup.py", line 5, in
from setuptools import setup, Extension
ImportError: No module named setuptools

BUMMER !

Go to http://pypi.python.org/packages/2.6/s/setuptools/ and download the current .egg version. I got a setuptools-0.6c9-py2.6.egg.sh.

Ok, now I do:
chmod u+x ./setuptools-0.6c9-py2.6.egg.sh
./setuptools-0.6c9-py2.6.egg.sh

to get greeted by
./setuptools-0.6c9-py2.6.egg.sh is not the correct name for this egg file.
Please rename it back to setuptools-0.6c9-py2.6.egg and try again.

Fine,
mv ./setuptools-0.6c9-py2.6.egg.sh ./setuptools-0.6c9-py2.6.egg
./setuptools-0.6c9-py2.6.egg



Processing setuptools-0.6c9-py2.6.egg
Copying setuptools-0.6c9-py2.6.egg to /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages
Adding setuptools 0.6c9 to easy-install.pth file
Installing easy_install script to /Library/Frameworks/Python.framework/Versions/2.6/bin
Installing easy_install-2.6 script to /Library/Frameworks/Python.framework/Versions/2.6/bin

Installed /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/setuptools-0.6c9-py2.6.egg
Processing dependencies for setuptools==0.6c9
Finished processing dependencies for setuptools==0.6c9


And we give it another try:

python setup.py build

yields


running build
running build_py
creating build
creating build/lib.macosx-10.3-fat-2.6
copying _mysql_exceptions.py -> build/lib.macosx-10.3-fat-2.6
creating build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/__init__.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/converters.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/connections.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/cursors.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/release.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
copying MySQLdb/times.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
creating build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/__init__.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/CR.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/ER.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/FLAG.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/REFRESH.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
copying MySQLdb/constants/CLIENT.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb/constants
running build_ext
building '_mysql' extension
creating build/temp.macosx-10.3-fat-2.6
gcc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -O3 -Dversion_info=(1,2,3,'gamma',1) -D__version__=1.2.3c1 -I/usr/local/mysql/include -I/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -c _mysql.c -o build/temp.macosx-10.3-fat-2.6/_mysql.o -Os -arch i386 -fno-common
gcc -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -g -bundle -undefined dynamic_lookup build/temp.macosx-10.3-fat-2.6/_mysql.o -L/usr/local/mysql/lib -lmysqlclient_r -lz -lm -o build/lib.macosx-10.3-fat-2.6/_mysql.so
ld warning: in build/temp.macosx-10.3-fat-2.6/_mysql.o, file is not of required architecture
ld warning: in /usr/local/mysql/lib/libmysqlclient_r.dylib, file is not of required architecture


I think the 2 warnings have to do with the "-arch ppc" in the 2nd invocation of gcc, but given that we also have the "-arch i386" there we're probably OK.

Next

sudo python setup.py install

Password:
running install
running bdist_egg
running egg_info
writing MySQL_python.egg-info/PKG-INFO
writing top-level names to MySQL_python.egg-info/top_level.txt
writing dependency_links to MySQL_python.egg-info/dependency_links.txt
reading manifest file 'MySQL_python.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'MySQL_python.egg-info/SOURCES.txt'
installing library code to build/bdist.macosx-10.3-fat/egg
running install_lib
running build_py
copying MySQLdb/release.py -> build/lib.macosx-10.3-fat-2.6/MySQLdb
running build_ext
creating build/bdist.macosx-10.3-fat
creating build/bdist.macosx-10.3-fat/egg
copying build/lib.macosx-10.3-fat-2.6/_mysql.so -> build/bdist.macosx-10.3-fat/egg
copying build/lib.macosx-10.3-fat-2.6/_mysql_exceptions.py -> build/bdist.macosx-10.3-fat/egg
creating build/bdist.macosx-10.3-fat/egg/MySQLdb
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/__init__.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/connections.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
creating build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/__init__.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/CLIENT.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/CR.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/ER.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/FIELD_TYPE.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/FLAG.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/constants/REFRESH.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb/constants
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/converters.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/cursors.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/release.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
copying build/lib.macosx-10.3-fat-2.6/MySQLdb/times.py -> build/bdist.macosx-10.3-fat/egg/MySQLdb
byte-compiling build/bdist.macosx-10.3-fat/egg/_mysql_exceptions.py to _mysql_exceptions.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/__init__.py to __init__.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/connections.py to connections.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/__init__.py to __init__.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/CLIENT.py to CLIENT.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/CR.py to CR.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/ER.py to ER.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/FIELD_TYPE.py to FIELD_TYPE.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/FLAG.py to FLAG.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/constants/REFRESH.py to REFRESH.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/converters.py to converters.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/cursors.py to cursors.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/release.py to release.pyc
byte-compiling build/bdist.macosx-10.3-fat/egg/MySQLdb/times.py to times.pyc
creating stub loader for _mysql.so
byte-compiling build/bdist.macosx-10.3-fat/egg/_mysql.py to _mysql.pyc
creating build/bdist.macosx-10.3-fat/egg/EGG-INFO
copying MySQL_python.egg-info/PKG-INFO -> build/bdist.macosx-10.3-fat/egg/EGG-INFO
copying MySQL_python.egg-info/SOURCES.txt -> build/bdist.macosx-10.3-fat/egg/EGG-INFO
copying MySQL_python.egg-info/dependency_links.txt -> build/bdist.macosx-10.3-fat/egg/EGG-INFO
copying MySQL_python.egg-info/top_level.txt -> build/bdist.macosx-10.3-fat/egg/EGG-INFO
writing build/bdist.macosx-10.3-fat/egg/EGG-INFO/native_libs.txt
zip_safe flag not set; analyzing archive contents...
creating dist
creating 'dist/MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg' and adding 'build/bdist.macosx-10.3-fat/egg' to it
removing 'build/bdist.macosx-10.3-fat/egg' (and everything under it)
Processing MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg
Copying MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg to /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages
Adding MySQL-python 1.2.3c1 to easy-install.pth file

Installed /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg
Processing dependencies for MySQL-python==1.2.3c1
Finished processing dependencies for MySQL-python==1.2.3c1


Looks good. Let's try it:


python
Python 2.6.2 (r262:71600, Apr 16 2009, 09:17:39)
[GCC 4.0.1 (Apple Computer, Inc. build 5250)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import MySQLdb
/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg/_mysql.py:3: UserWarning: Module _mysql was already imported from /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/MySQL_python-1.2.3c1-py2.6-macosx-10.3-fat.egg/_mysql.pyc, but /Users/bhapca/Downloads/MySQL-python-1.2.3c1 is being added to sys.path

huh ?

>>> dir(MySQLdb)
['BINARY', 'Binary', 'Connect', 'Connection', 'DATE', 'DATETIME', 'DBAPISet', 'DataError', 'DatabaseError', 'Date', 'DateFromTicks', 'Error', 'FIELD_TYPE', 'IntegrityError', 'InterfaceError', 'InternalError', 'MySQLError', 'NULL', 'NUMBER', 'NotSupportedError', 'OperationalError', 'ProgrammingError', 'ROWID', 'STRING', 'TIME', 'TIMESTAMP', 'Time', 'TimeFromTicks', 'Timestamp', 'TimestampFromTicks', 'Warning', '__all__', '__author__', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__', '__revision__', '__version__', '_mysql', 'apilevel', 'connect', 'connection', 'constants', 'debug', 'escape', 'escape_dict', 'escape_sequence', 'escape_string', 'get_client_info', 'paramstyle', 'release', 'result', 'server_end', 'server_init', 'string_literal', 'test_DBAPISet_set_equality', 'test_DBAPISet_set_equality_membership', 'test_DBAPISet_set_inequality', 'test_DBAPISet_set_inequality_membership', 'thread_safe', 'threadsafety', 'times', 'version_info']
>>>

Seems OK I guess.

Bottom line. The steps above seem to result in 2 different versions of Python coexisting side by side, one that came from Apple in

/System/Library/Frameworks/Python.framework/Versions/2.5/bin/python

and the one I installed in

/Library/Frameworks/Python.framework/Versions/2.6/bin/python

Monday, July 06, 2009

cron jobs terminate prematurely on Godaddy accounts

I've been using a large tarball file to upload my online store updates to godaddy and a cron job to unpack the tarball.

As the size of that tarball increased, due to adding more products, I noticed that the tar process would terminate prematurely, causing big issues, with the store left half-updated, in an inconsistent state.

I've been suspecting the folks at godaddy running some sort of watchdog timer and killing off processes that take longer to run.

Well, according to some reports, that indeed seems to be the case.

One option to go around this would be to break the large tarball in several smaller ones, that won't keep tar humming for too long. Also I should perhaps consider sending only actual delta changes instead overwriting the whole store in one go.

Friday, July 03, 2009

connection pools time-outs in GlassFish

I've been using JDBC connection pools and JMS connection factories for a recent project and upon deployment on GlassFish I did a sanity test to confirm that everything is OK. It passed the test.

So off I go, leaving it running on an Amazon EC2 instance. When I check on it about 3 days later I notice that it doesn't work anymore ... "server error", the UI informs me (which is a bad error message for the end users, whom might not know what a server (those working in restaurants) has to do with it). Anyway, by looking at the logs I see a few of these:


Exception: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

and

Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after statement closed.


Now the way I implemented this was in the "init" method of the servlet I would create my instances of javax.jms.Connection and java.sql.Connection as member fields of the servlet, hoping to reuse them for the lifetime of the servlet.

The errors in the logs seem to indicate that those connections get yanked out while my servlet is running, albeit idle. Not cool.

Looking at the admin console I see an "Idle Timeout:" configuration setting which defaults to 300 sec for both my JDBC connection pool and JMS connection factory. I changed that to 300000000. I have the feeling that this is going to fix the issue, but I need to run it for a while to confirm.

I'm not sure if this is the right thing of approaching this, so if you know any better please add a comment.

UPDATE:
It seems that changing the configuration settings for GlassFish is not enough to fix the problem.

Likely the wait_timeout configuration setting of MySQL has something to do with this too. By default mysqld will close idle connections after 8 hours, so we'd need to increase that to up to the max value of 31536000. One way to do that is through a configuration file (e.g. /etc/my.cnf, where we'd add a line with 'wait_timeout= 31536000' under the [mysqld] section.

Yet a better approach would be to catch the exceptions mentioned above in the servlet code and recreate the connection to the DB.

ANOTHER UPDATE:
It seems that catching the exception and re-opening the connection in the servlet code doesn't work very well. I get the following exception when trying to re-establish the connection:


Exception:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
...


Other people have experienced this too. One workaround indicated there, like I mentioned above, is to tinker with wait_timeout configuration of MySQL.

Another avenue to explore would be the "Connection Validation" capabilities of the JDBC connection pool. That's easily available through GlassFish admin console. According to the docs "Optionally, the application server can validate connections before they are passed to applications. This validation allows the application server to automatically reestablish database connections if the database becomes unavailable due to network failure or database server crash. Validation of connections incurs additional overhead and slightly reduces performance."

It'd be interested to see if the "table" validation method fixes this issue.

Monday, June 29, 2009

java hangs after installing "Java for Mac OS X 10.5 Update 4"

I had been experiencing some issues with Java on my MacBook after an update was pushed by Apple.

Had to jump through some hoops, but I came up with a workaround. For more details see this post.

Tuesday, June 23, 2009

How to download and install Nokia .wgz widgets OTA

According to Nokia we should be using an "AddType x-nokia-widget .wgz" directive to change the settings of web server to add a new mapping from the filename to a new MIME type.

Tough some people don't have access to server settings, let alone that Nokia's instructions don't include the complete MIME type (application/x-nokia-widget) so I'm not sure that what they suggested would work well.

Another way is to include the appropriate HTTP response headers through a script running on the server side.

This one, writteh in PHP, seems to be doing the job just fine. Pointing the S60 browser to its URL downloads the widget and starts its installation.


$filename = 'example.wgz';

header('Content-type: application/x-nokia-widget');
header('Content-Disposition: attachment; filename="'.$filename.'"');
readfile($filename);

Friday, June 19, 2009

java.rmi.server.UID is not random

Well, here's an unfortunate result of having different ways of doing the same thing in Java.

I needed a way to generate a random unique ID to be used as an authentication token. So I thought hmmm a sort of UID ought to do it. So the first candidate that Google suggested was

java.rmi.server.UID

Running a quick test gave me the following results in 2 subsequent runs: '-31a4aa0:121f7402438:-7f1f' and '-31a4aa0:121f7402438:-7f1e'. Epic fail. So much for randomness.

Looking for alternatives,
java.util.UUID

seems to be a better choice. In particular its

randomUUID()

factory method seems to claim cryptographic strength.

Tuesday, June 09, 2009

How to run GlassFish on the default HTTP port 80 on Solaris

If GlassFish is run as non-root process, with reduced privileges, as recommended, it won't be able to bind to ports < 1024. You'll get an exception:


java.net.BindException: Permission denied: 80 at com.sun.enterprise.web.connector.grizzly.SelectorThread.initEndpoint


To get around this you could set up a domain that has the ability to bind to standard Unix ports, including the port 80. For this you use the --serviceproperties net_privaddr flag of asadmin create-service command.


You can use the following steps. Replace the italic portion with your specific settings.


/opt/gf21/glassfish/bin# ./asadmin create-domain --adminport 4848 --instanceport 80 --profile cluster --user admin --domaindir /opt/gf21/glassfish/domains ptmp

Please enter the admin password>

Please enter the admin password again>

Please enter the master password [Enter to accept the default]:>

Please enter the master password again [Enter to accept the default]:>

Using port 4848 for Admin.

Using port 80 for HTTP Instance.

Using default port 7676 for JMS.

Using default port 3700 for IIOP.

Using default port 8181 for HTTP_SSL.

Using default port 3820 for IIOP_SSL.

Using default port 3920 for IIOP_MUTUALAUTH.

Using default port 8686 for JMX_ADMIN.

On Unix platform, port numbers below 1024 may require special privileges.

Domain being created with profile:cluster, as specified on command line or environment.

Security Store uses: JKS

Domain ptmp created.


You need to create a file with the admin credentials:


cat > /opt/gf21/glassfish/domains/ptmp/.aspass

AS_ADMIN_USER=admin

AS_ADMIN_PASSWORD=something

AS_ADMIN_MASTERPASSWORD=something

^D


/opt/gf21/glassfish/bin# ./asadmin create-service --passwordfile /opt/gf21/glassfish/domains/ptmp/.aspass --type das --serviceproperties net_privaddr /opt/gf21/glassfish/domains/ptmp

The Service was created successfully. Here are the details:

Name of the service:application/SUNWappserver/ptmp

Type of the service:Domain

Configuration location of the service:/opt/gf21/glassfish/domains

Manifest file location on the system:/var/svc/manifest/application/SUNWappserver/ptmp_opt_gf21_glassfish_domains/Domain-service-smf.xml.

The service could be enabled using svcadm command.

Command create-service executed successfully.


Ckeck that the newly created service is online. 


# svcs -a | grep ptmp

online         14:26:14 svc:/application/SUNWappserver/ptmp:default


If not make it so.

# svcadm enable svc:/application/SUNWappserver/ptmp:default


An extra sanity check:

# netstat -a | grep 80



Time-out when calling file_get_contents on PHP scripts hosted on Godaddy accounts

I noticed that if you're using a Godaddy shared web hosting plan you're limited to calling file_get_contents only on URLs that use the standard HTTP port 80


It may be a firewall rule that they have in place.


So if you have an url like http://app.example.com:8080/do?param=value, 

the call to file_get_contents will hang and eventually timeout, 

even if the same url is accessible directly from within a browser.


If you control the called web component you may be able to change it 

so that it would listen on the standard port 80.

Class name is wrong or classpath is not set for : com.mysql.jdbc.jdbc2.optional.MysqlDataSource

If you get this error when trying to ping a newly created JDBC connection pool from within GlassFish admin console, it's likely because you're missing the JDBC driver mysql-connector-java-5.1.*-bin.jar under the lib/ext folder on your domain. 


To fix it copy that file there (e.g. ~/glassfish-v2ur2/domains/domain1/lib/ext/mysql-connector-java-5.1.5-bin.jar ), restart the domain and try again.

You can get the latest copy of the driver from here.


Update: There was at least a comment below, indicating that this method may not work for GlassFish version 3.1.1 and the more recent JDBC connection drivers. Your best bet may be to use the official docs, for the particular version of GlassFish you're running. For 3.1.1 one doc and another doc indicates that mysql-connector-java-5.1.14-bin.jar should be placed under the lib folder, not under lib/ext folder. 

Saturday, June 06, 2009

How to troubleshoot the bootup of GlassFish + MySQL image on OpenSolaris

I've been using an Amazon image with GlassFish+MySQL+OpenSolaris. As I'm no sysadmin, I relied on a prebuilt image furnished by Sun as a base for my development.

Still I've been experiencing  various issues at bootup, when the app server wouldn't start. This is especially true when you reboot the instance with Amazon EC2 tools. It behaves better if you terminate and restart the instance.

So I devised a set of steps to ensure that the thing gets working. 


Check if the services are running:

svcs  | grep mysql

svcs  | grep glassfish


If not, start them:

svcadm restart svc:/application/mysql:default

svcadm restart svc:/application/glassfish/domain1:default


Keep an eye on the server log

e.g. tail -f /opt/gf21/glassfish/domains/domain1/logs/server.log


If that reports failure, you have work to do.


Sometimes the app server can't start due to a previous process not having released the essentials TCP ports. Do a

netstat -a | grep 3700 



if it shows some daemons listening do a

ps -ef

look for usr/jdk/instances/jdk1.6.0/jre/../bin/java -Dcom.sun.aas.instanceRoot=/opt/gf2


That may be a stale instance. Try to kill -9 and look for the process above to be vanished and the port 3700 to be free.


Try again 

svcadm restart svc:/application/glassfish/domain1:default


transient error: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

While experimenting with an Amazon OpenSolaris+GlassFish+MySQL AMI. I have been getting some weird errors when launching mysql. 

-bash-3.2$ mysql -u root -p

Enter password: 

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)


I don't know if it has to do with this particular image (install/config issue) or if it's a side effect of the fact that's run on a virtual server, but a quick workaround seems to be:

svcadm restart mysql ran as root 

Friday, June 05, 2009

error when bundling OpenSolaris - based AMI on Amazon EC2

I needed a server in the cloud for a project, with Glassfish and MySQL installed. Having found a pre-built AMI (Amazon Machine Image) based on OpenSolaris it seemed to be fit for my purpose.

After kicking its tires I decided to place my customizations and re-bundle an image that would have them on upon reboot.

So I followed along the instruction from the Getting Started guide (http://docs.amazonwebservices.com/AWSEC2/latest/GettingStartedGuide/). Well, no good. The bundling failed with the following error reported by ec2-bundle-vol:


Cloning / into image file /mnt/ptmpimage...
Excluding:
/export/home
/rpool
/export
/
/mnt
/mnt
/mnt/ptmpimage
/mnt/ec2-bundle-workspace
Creating flash archive of file system...
Time: 0.086058s
Time: 0.023259s
Time: 0.229003s
Time: 0.023268s
Time: 0.113336s
Time: 0.023153s
Time: 0.036836s
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
devfsadm: disk_link: invalid disk device number (2051)
Time: 0.400378s
ERROR: Failed to evaluate 'flar create -n ec2.archive -S -R / -x /export/home/gf21 -x /export/home/mysql -x /rpool/boot -x /rpool/etc -x /export/home -x /bin -x /boot -x /dev -x /devices -x /etc -x /export -x /home -x /kernel -x /lib -x /lost+found -x /media -x /mnt -x /net -x /opt -x /platform -x /proc -x /.profile -x /root -x /rpool -x /sbin -x /sysbench -x /system -x /tmp -x /usr -x /var -x /mnt/cert-SGB3LC7W3STUADHK6YLJGLH45V6NGQQU.pem -x /mnt/ec2-bundle-workspace -x /mnt/pk-SGB3LC7W3STUADHK6YLJGLH45V6NGQQU.pem -x /mnt/cert-SGB3LC7W3STUADHK6YLJGLH45V6NGQQU.pem -x /mnt/ec2-bundle-workspace -x /mnt/pk-SGB3LC7W3STUADHK6YLJGLH45V6NGQQU.pem -x /mnt/ptmpimage -x /mnt/ec2-bundle-workspace /mnt/ec2-bundle-workspace/archive 2> /dev/null'. Reason: .




It turns out that Solaris AMIs have a different bundling procedure, so the instructions provided by Amazon in their guide don't apply (I think they're for Fedora (or other RedHat derrivatives) images).

For instructions specific to Solaris see
this.

Sunday, May 31, 2009

"The directory or file cannot be created (0x52)" error while installing S60 5th Edition SDK


While installing some of the newer SDK from Forum Nokia I'm getting greeted by the following error:



Nice, after looking at that bloated folder it's clearly that my FAT32 partition can't cope with the multitude of files that Nokia chose to dump there.

A quick look at FN reveals that others have the same problem (see here) and a suggestion for a fix, by deleting the resources for languages other than English.

So I went ahead an wrote the following script that does the trick:



import fnmatch
import os
import time

path = 'C:\\S60\\devices\\S60_5th_Edition_SDK_v1.0\\epoc32\\release\\winscw\\udeb\\z\\resource'

while True:

try:
for file in os.listdir(path):
if (fnmatch.fnmatch(file, '*.r0[023456789]') or
fnmatch.fnmatch(file, '*.r[123456789][0123456789]') or
fnmatch.fnmatch(file, '*.r[123456789][0123456789][0123456789]')):
print file
os.remove(path + '\\' + file)

except IOError as (errno, strerror):
print "I/O error({0}): {1}".format(errno, strerror)
except WindowsError as (errno, strerror):
print "Windows error({0}): {1}".format(errno, strerror)
except:
print "Unexpected error:", sys.exc_info()[0]
raise

time.sleep(10)



Update the path variable with your installation path and run this script after you hit the first error and chose retry. When you're done with the install kill the script.

Monday, May 25, 2009

missing WRT widget components when packaging with Aptana Studio

I've been using the Aptana Studio Community Edition and its plugin for creating S60 WRT widgets. It has a few good features that increase productivity, like a decent editor with code formatting, integrated contextual help, packaging and deploying functioning.

One annoying issue I found was that after adding new components to the widget, e.g. new .js, .png files, they are not picked up for packaging, unless you do a project refresh (right-click on the project in the project pane on the left side of the screen and chose "Refresh").

Failing to do this may result in wasting time debugging the unexpected behavior. One such step in debugging could be renaming the .wgz package to .zip and exploring that zip's content to check for the newly added components. If they are missing, surely a refresh is needed.

Friday, May 15, 2009

Unneeded white space in textarea

I noticed an annoying behavior of textarea elements that have white space between the opening and closing tags. That space shows up as the initial value of that element in the browser. 

I've been using an edit control built on top of a textarea for a recent project and I noticed that upon clicking on the control to get focus, the caret cursor would not land in the top let corner of the control, instead it would have a few characters of left padding. 

That's because my Komodo Edit IDE was formatting the code by putting the end tag on a different line and would add sufficient white space for a balanced indentation. That was causing the padding to appear. 

The workaround is to keep the textarea element with a truly empty value like this:
<textarea></textarea>

Wednesday, May 13, 2009

How to install GlassFish on CentOS and other Redhat derivatives

First you need to have Java installed, I prefer OpenJDK, which is available from EPEL , a community-run project which makes Fedora packages available to users of Red Hat Enterprise Linux 5, CentOS 5, and other RHEL 5 derivatives. First install the package that enables the EPEL repository:

su -c "rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-2.noarch.rpm"


Then fetch the packages needed:

su -c "yum install java-1.6.0-openjdk"

su -c "yum install java-1.6.0-openjdk-devel"


Set the JAVA_HOME environment variable to point to the location of the JDK installation. To find that location you can do a which java and repeated  ls -l to follow the links to the concrete location.

Do the installation, e.g.:

java -Xmx256m -jar glassfish-installer-v2.1-b60e-linux.jar


Add the as-install/bin/ directory to the PATH environment variable.

To connect to the admin console, open a web browser to on http://hostname:4848

For login, the default admin user name is admin and the password is adminadmin






  

Tuesday, May 12, 2009

How to enable access logging in GlassFish

For debugging, monitoring and audit purposes it's sometimes useful to analyze access logs. 

By default Sun's GlassFish server has such logging disabled. It can be enabled by editing the domain.xml file (e.g. domains/domain1/config/domain.xml) and changing the accessLoggingEnabled attribute of the http-service element to true.

Following the restart of GlassFish the logs are available under the logs/access folder, (e.g. domains/domain1/logs/access/).

Driving Recorder at 5000 downloads

Following the posting of my Driving Recorder application on GetJar at the beginning of the year I just went through the milestone of passing the 5000th download. 

So far the feedback from these people trying the app has been mute. The popularity seem to be holding steady, but the lack of feedback, and purchases :), makes me think that either their reporting system is broken or those numbers are mostly the result of site duplication robots.

How to install VMWare tools on CentOS 5.0

VMWare tools are needed for a smooth integration between the guest and host OS. I'm currently using VMWare Fusion for Mac, and I needed CentOS for a project. Here are the steps I went through:

In CentOS do yum install gcc kernel-devel

Compare the version of OS, reported by the uname -r with that of kernel headers, reported by rpm -q kernel-devel. If there's a mismatch, update the headers with yum -y upgrade kernel kernel-devel and reboot.

In WMware Fusion go to the Virtual Machine menu -> Install VMware Tools. 

In CentOS do a mount /dev/cdrom /mnt. Now you should have a gzipped tar with the tools in /mnt. Extract them into the /tmp folder with tar -C /tmp -zxvf /mnt/VMwareTools*.tar.gz

cd /tmp/vmware-tools-distrib
./vmware-install.pl and follow the prompts.