Re: AW: Basic question about application configuration
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Hash: SHA256
Mathieu,
On 10/24/19 14:26, Mathieu Dubois wrote:
> Dear Christopher,
>
> Le 24/10/2019 à 00:36, Christopher Schultz a écrit :
>> -BEGIN PGP SIGNED MESSAGE- Hash: SHA256
>>
>> Mathieu,
>>
>> On 10/23/19 17:23, Mathieu Dubois wrote:
>>> I noticed that the application also need to access to a
>>> directory to store the result of some computation usually
>>> outside the location of tomcat (the results can be rather
>>> large). As for the DB this depends on each instance of the
>>> application. Is there a similar mechanism for such a case ?
>> It's not exactly clear what you are asking, but it sounds like
>> you are looking for a configuration similar to the JNDI binding
>> that can be split between conf/server.xml and
>> META-INF/context.xml for connecting to a database.
>>
>> You have some choices, here, and the "right one" probably will
>> require you to make a decision based upon your requirements.
>>
>> In WEB-INF/web.xml, there are some optional configuration data
>> called "context parameters". They look something like this:
>>
>> > xmlns="http://java.sun.com/xml/ns/javaee;
>> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance;
>> xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
>> http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd; version="3.0"
>> metadata-complete="true"> You can
>> put whatever you want in here. It's just documentation for human
>> readers.
>> my-configuration-property-name
>> my value ...
>>
>>
>> If you want to put, for example, a directory path in here for
>> storing temporary files, you could do it like this:
>>
>> Path to the temporary file
>> directory where we write filed.
>> fr.cns.genoscope.appname.tmpfiledir
>> /tmp/app/temp-files
>> ...
>>
>> In order to use these configuration values, your code needs to
>> read them explicitly, so you'll need to make some code changes in
>> order to put your configuration into WEB-INF/web.xml. Something
>> like this in your servlet:
>>
>> String tmpDir =
>> getServletContext().getInitParam("fr.cns.genoscope.appname.tmpfiledir
");
>>
>>
// ... use the tmpDir for all your file-writing needs
>>
>> Now, WEB-INF/web.xml is bundled inside your WAR file and, as
>> you've mentioned, it's not very flexible with your builds. So,
>> here's what you can do:
>>
>> The file META-INF/context.xml (also bundled within your
>> application's WAR file -- hold that thought for a minute) can be
>> used to override the values of your context-param values, like
>> this:
>>
>> > name="fr.cns.genoscope.appname.tmpfiledir"
>> value="/usr/local/other/location/for/client/X" override="true"/>
>> ...
>>
>> More info can be found at:
>> http://tomcat.apache.org/tomcat-9.0-doc/config/context.html#Context_P
ara
>>
>>
meters
>>
>> So, you could put the right value into WEB-INF/web.xml (which is
>> inconvenient) or into META-INF/context.xml (which is also
>> inconvenient) or -- and here's where things get a little
>> interesting - -- you can copy the file META-INF/context.xml from
>> the WAR file and put it into Tomcat's configuration directory
>> structure like this:
>>
>> conf/[enginename]/[hostname]/[appname].xml
>>
>> ...and it will *override* the file supplied by the WAR file in
>> META-INF/context.xml. So you get to use the same WAR file
>> everywhere and customize those XML files on a per-client basis.
>>
>> Above, the [enginename] is almost always "Catalina" and matches
>> the "name" attribute of the in your conf/server.xml
>> file. By default, it's name="Catalina" and pretty much nobody
>> ever changes it. Your [hostname] comes from the "name" attribute
>> of the in which your context/webapp is defined, and is
>> often just "localhost" although it would be anything depending
>> upon your environment. The [appname] is whatever you want it to
>> be: the [appname] sets the context-path of the application. But
>> the [appname].xml must match your [appname].war file name.
>>
>> So if you don't mind modifying your code a little, this can get
>> your a lot of flexibility.
>>
>> This feature goes back to Tomcat 5.5, so you should be able to
>> use it. I'd of course encourage you to look at upgrading to at
>> least Tomcat 8.5 in the near-term. You may find that you can just
>> drop-in the latest Tomcat 8.5.x in place of your Tomcat 5.5 and
>> everything still works. (You will have to re-write your
>> conf/server.xml file from scratch, as those files are not
>> compatible between major releases.)
>
> Thanks for your in-depth explanation, it really helps. If I
> summarize, I can use conf/[enginename]/[hostname]/[appname].xml to
> configure both the DB connection (with a Resource) and the
> directory where to write files (with a param). That sounds exactly
> like what we need.
You can do exactly that.
In order to use context-params, though, you will probably need to
modify your code to pick-up that configuration. Hopefully, it's not
too much trouble to do
Re: AW: Basic question about application configuration
Dear Christopher,
Le 24/10/2019 à 00:36, Christopher Schultz a écrit :
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256
Mathieu,
On 10/23/19 17:23, Mathieu Dubois wrote:
I noticed that the application also need to access to a directory
to store the result of some computation usually outside the
location of tomcat (the results can be rather large). As for the DB
this depends on each instance of the application. Is there a
similar mechanism for such a case ?
It's not exactly clear what you are asking, but it sounds like you are
looking for a configuration similar to the JNDI binding that can be
split between conf/server.xml and META-INF/context.xml for connecting
to a database.
You have some choices, here, and the "right one" probably will require
you to make a decision based upon your requirements.
In WEB-INF/web.xml, there are some optional configuration data called
"context parameters". They look something like this:
http://java.sun.com/xml/ns/javaee;
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance;
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd;
version="3.0"
metadata-complete="true">
You can put whatever you want in here. It's just documentation
for human readers.
my-configuration-property-name
my value
...
If you want to put, for example, a directory path in here for storing
temporary files, you could do it like this:
Path to the temporary file directory where we write
filed.
fr.cns.genoscope.appname.tmpfiledir
/tmp/app/temp-files
...
In order to use these configuration values, your code needs to read
them explicitly, so you'll need to make some code changes in order to
put your configuration into WEB-INF/web.xml. Something like this in
your servlet:
String tmpDir =
getServletContext().getInitParam("fr.cns.genoscope.appname.tmpfiledir");
// ... use the tmpDir for all your file-writing needs
Now, WEB-INF/web.xml is bundled inside your WAR file and, as you've
mentioned, it's not very flexible with your builds. So, here's what
you can do:
The file META-INF/context.xml (also bundled within your application's
WAR file -- hold that thought for a minute) can be used to override
the values of your context-param values, like this:
...
More info can be found at:
http://tomcat.apache.org/tomcat-9.0-doc/config/context.html#Context_Para
meters
So, you could put the right value into WEB-INF/web.xml (which is
inconvenient) or into META-INF/context.xml (which is also
inconvenient) or -- and here's where things get a little interesting
- -- you can copy the file META-INF/context.xml from the WAR file and
put it into Tomcat's configuration directory structure like this:
conf/[enginename]/[hostname]/[appname].xml
...and it will *override* the file supplied by the WAR file in
META-INF/context.xml. So you get to use the same WAR file everywhere
and customize those XML files on a per-client basis.
Above, the [enginename] is almost always "Catalina" and matches the
"name" attribute of the in your conf/server.xml file. By
default, it's name="Catalina" and pretty much nobody ever changes it.
Your [hostname] comes from the "name" attribute of the in which
your context/webapp is defined, and is often just "localhost" although
it would be anything depending upon your environment. The [appname] is
whatever you want it to be: the [appname] sets the context-path of the
application. But the [appname].xml must match your [appname].war file
name.
So if you don't mind modifying your code a little, this can get your a
lot of flexibility.
This feature goes back to Tomcat 5.5, so you should be able to use it.
I'd of course encourage you to look at upgrading to at least Tomcat
8.5 in the near-term. You may find that you can just drop-in the
latest Tomcat 8.5.x in place of your Tomcat 5.5 and everything still
works. (You will have to re-write your conf/server.xml file from
scratch, as those files are not compatible between major releases.)
Thanks for your in-depth explanation, it really helps. If I summarize, I
can use conf/[enginename]/[hostname]/[appname].xml to configure bith the
DB connection (with a Resource) and the directory where to write files
(with a param). That sounds exactly like what we need.
Thanks again,
Mathieu
--
Mathieu Dubois - IR - UMR 8030 équipe LABGeM
CEA - Genoscope. 2 rue Gaston Crémieux. 91057 Evry Cedex France.
Bureau B07
+33 1 60 87 53 35
-
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
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Re: AW: Basic question about application configuration
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256
Mathieu,
On 10/23/19 17:23, Mathieu Dubois wrote:
> I noticed that the application also need to access to a directory
> to store the result of some computation usually outside the
> location of tomcat (the results can be rather large). As for the DB
> this depends on each instance of the application. Is there a
> similar mechanism for such a case ?
It's not exactly clear what you are asking, but it sounds like you are
looking for a configuration similar to the JNDI binding that can be
split between conf/server.xml and META-INF/context.xml for connecting
to a database.
You have some choices, here, and the "right one" probably will require
you to make a decision based upon your requirements.
In WEB-INF/web.xml, there are some optional configuration data called
"context parameters". They look something like this:
http://java.sun.com/xml/ns/javaee;
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance;
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd;
version="3.0"
metadata-complete="true">
You can put whatever you want in here. It's just documentation
for human readers.
my-configuration-property-name
my value
...
If you want to put, for example, a directory path in here for storing
temporary files, you could do it like this:
Path to the temporary file directory where we write
filed.
fr.cns.genoscope.appname.tmpfiledir
/tmp/app/temp-files
...
In order to use these configuration values, your code needs to read
them explicitly, so you'll need to make some code changes in order to
put your configuration into WEB-INF/web.xml. Something like this in
your servlet:
String tmpDir =
getServletContext().getInitParam("fr.cns.genoscope.appname.tmpfiledir");
// ... use the tmpDir for all your file-writing needs
Now, WEB-INF/web.xml is bundled inside your WAR file and, as you've
mentioned, it's not very flexible with your builds. So, here's what
you can do:
The file META-INF/context.xml (also bundled within your application's
WAR file -- hold that thought for a minute) can be used to override
the values of your context-param values, like this:
...
More info can be found at:
http://tomcat.apache.org/tomcat-9.0-doc/config/context.html#Context_Para
meters
So, you could put the right value into WEB-INF/web.xml (which is
inconvenient) or into META-INF/context.xml (which is also
inconvenient) or -- and here's where things get a little interesting
- -- you can copy the file META-INF/context.xml from the WAR file and
put it into Tomcat's configuration directory structure like this:
conf/[enginename]/[hostname]/[appname].xml
...and it will *override* the file supplied by the WAR file in
META-INF/context.xml. So you get to use the same WAR file everywhere
and customize those XML files on a per-client basis.
Above, the [enginename] is almost always "Catalina" and matches the
"name" attribute of the in your conf/server.xml file. By
default, it's name="Catalina" and pretty much nobody ever changes it.
Your [hostname] comes from the "name" attribute of the in which
your context/webapp is defined, and is often just "localhost" although
it would be anything depending upon your environment. The [appname] is
whatever you want it to be: the [appname] sets the context-path of the
application. But the [appname].xml must match your [appname].war file
name.
So if you don't mind modifying your code a little, this can get your a
lot of flexibility.
This feature goes back to Tomcat 5.5, so you should be able to use it.
I'd of course encourage you to look at upgrading to at least Tomcat
8.5 in the near-term. You may find that you can just drop-in the
latest Tomcat 8.5.x in place of your Tomcat 5.5 and everything still
works. (You will have to re-write your conf/server.xml file from
scratch, as those files are not compatible between major releases.)
Hope that helps,
- -chris
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Re: AW: Basic question about application configuration
Hi again, I noticed that the application also need to access to a directory to store the result of some computation usually outside the location of tomcat (the results can be rather large). As for the DB this depends on each instance of the application. Is there a similar mechanism for such a case ? Thanks in advance, Mathieu -- Mathieu Dubois - IR - UMR 8030 équipe LABGeM CEA - Genoscope. 2 rue Gaston Crémieux. 91057 Evry Cedex France. Bureau B07 +33 1 60 87 53 35 - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: AW: Basic question about application configuration
Hi Bernd, Le 23/10/2019 à 06:55, bernd.sch...@daimler.com a écrit : Hi Mathieu, -Ursprüngliche Nachricht- Von: Mathieu Dubois Gesendet: Mittwoch, 23. Oktober 2019 03:00 An: users@tomcat.apache.org [SNIP] I have read a bit about Tomcat and if I understand correctly, the correct way to do is to declare a Resource in the configuration of each server which represents the DB to use and then adapt the code (in particular Hibernate configuration) to use this Resource based on it's name. Then the same WAR file can be deployed on any servers provided it's configured without maven (i.e. I just have to upload the WAR file and voilà). Is that correct ? Yes, it is a common approach in the Java Application world called jndi. So your app would also work on a different application server like Wildfly or Liberty. But the way you define it in your application server differs, So see here for comparison: https://tomcat.apache.org/tomcat-8.0-doc/jndi-resources-howto.html https://developer.jboss.org/thread/279940 Thank you very much for your insight. It will sure help us to restructure the project. Namaste, Mathieu -- Mathieu Dubois - IR - UMR 8030 équipe LABGeM CEA - Genoscope. 2 rue Gaston Crémieux. 91057 Evry Cedex France. Bureau B07 +33 1 60 87 53 35 - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
