If I externalize part of my Grails configuration, must I restart my container for the change to be found? Is there any workaround to this if so? Thanks.
No, there's no automatic watch for changes to external config files. There's a good solution here that involves making a controller request to trigger a reload: http://jetlet.blogspot.com/2011/02/reload-external-config-file-dynamically.html
There's also this plugin, which looks like it hasn't been updated in a long time and may not work: http://www.grails.org/plugin/reloadable-config
Chiming in late here, but there's also
http://www.grails.org/plugin/external-config-reload
Related
In Grails 2 we used the "External configuration plugin", which included the method checkNow() for checking and refreshing values from an external config file.
Does it exist a simple approach for doing something similar in Grails 4+? I have seen references to Spring Cloud Config Server, but it seems a bit overkill for me. All I really want to do is be able to (now and then) update a config value in runtime. It could also be purely by a few lines of code, and does not have to originate from changes in the config file. This would avoid having to restart our server for minor changes in config. Thanks!
I'm replying to myself with a ridiculously simple answer: "just change it". Using the console plugin (or any other form of code execution), I can just assign grailsApplication.config.any.property a new value. It won't persist and it won't update any listeners or anything. But it is a glaringly obvious solution that I just assumed wouldn't work due to the getProperty() calls (I interpreted the name as reading from file) and googled discussions about Spring Cloud Config.
So, move on... nothing to see here. Just mild embarrassment :-P
change a config.properties file in a jar / war file in runtime and hotdeploy the changes ?
my requirement is something as follows, we have a "config.properties" in a jar/war file , i have to open the file through a webpage and after the user has made necessary changes to it, i have to update the "config.properties" in jar/war file and hot deploy it. can we achieve this feat ? if so can you please point me to relevant sites/documents so that i can jumpstart on this.
I will strongly recommend your architecht rethink this solution. What you describe should be done through JNDI or a similar technique, not through reloading properties.
Deployments should be considered static - that any given web container allows for magic trickery should not be depended on, and WILL break some day (most likely at the most inconvenient time).
You've got a couple of problems off the top of my head:
ensuring that nothing is holding static references to a java.util.Properties that has previously loaded your config.properties file.
most servlet engines will unpack your war to a working directory so the properties file you load won't be the one in the war, it will be the unpacked one. This means your changes
will be overwritten when you restart the servlet engine because this is typically one of the points the war is unpacked.
While these problems aren't insurmountable I've always found it much easier to implement this sort of behavior by storing the properties in JNDI (as Thorbjørn suggests) or a database (while being careful about the static references I mentioned in point 1).
The JNDI/database solution has the nice side effect of easing deployment into multiple environments because each typically has it's own registry/database.
Even that I agree with the comments explained before, I could suggest one solution:
Apache Commons Configuration extension gives you the posibility to do something like:
config.setReloadingStrategy(new FileChangedReloadingStrategy());
That could make the trick to change the configuration file on a runtime basis with no code at all.
However, like JNDI and other methods of web application configuration, the security is a concern. Be careful on which parameters you can/must be able to configure.
Apparently I'm terrible at Googling. All I want to do is have the ability to read my web service URL from a config file in my PhoneGap app. Also, be able to modify that value during the build process. Is this named alot different in Xcode? I think I need to save this value in the plist file. If that's the case, then I can just set a user-setting in my build configuration stuff to have it change depending on which build type, Dev/Release.
If that's true, how do I access this from PhoneGap?
I'm guessing this question will get closed, but where else do I go for help...
plist file for cordova project already depreciate since v2.2. Cordova v2.3 start using config.xml.
Target > Edit Scheme
You could probably use hooks to accomplish everything that you are trying to do without changing around the config.xml file, but I'm not entirely sure this is supported with Phonegap (it is with Cordova.)
Check out the official help page to use the /hooks/ folder to modify anything during the build process: https://github.com/apache/cordova-cli/blob/master/templates/hooks-README.md
This blog post also seems pretty useful: http://devgirl.org/2013/11/12/three-hooks-your-cordovaphonegap-project-needs/ it talks about changing things based on the environment and I'm sure it'd be easy to extend that to changing based on dev/release.
You could store the link to your web service probably as a config variable. I'm trying to figure out how you can add a config variable and will report back if I get it. In the mean time you could probably just have something like a server.txt file that you change with hooks.
I'm wondering where utility code can be placed, that doesn't cause a restart of container. Updating controllers doesn't cause a container restart & the updated code is available to run (great), but I wanted a more general library/utility place for my utility code.
Putting the code in /utils or in src/groovy does cause a restart on save, at least using Intellij, but I imagine this is the same regardless of where Grails is developed.
Perhaps you have some general info/insights on how Grails does this -- includes new code but doesn't need to restart the container, if that's only special to controllers?
(v. 1.3.7)
You're out of luck out of the box unless you want to use 2.0. The alternative is to turn off auto-reloading and add in something like jrebel. See this blog for details.
I have an app that runs as a service, and I'd like it to be able to check a URL to see if a new version is available, and if so to download and install it. I can manually hack something together, but would be great if I could create an MSI package to update the service, and any other components that are part of my distribution. I'd also like it to be done without any UI, so the user is unaware of the update.
Are there any good solutions for this?
This could be tricky depending on what your update might want to do.
If you intend on deleting and re-installing the service, this may require a reboot, which will certainly be visible to the user.
In order to replace the components of the service, the service has to be stopped first. If your service itself is detecting the update availability, it may have to kick off another process to stop the service, run the installer/updater and then restart the service.
Try installer.codeeffects.com. It has this feature.
You could try MEF (http://www.codeplex.com/MEF) and use
[Import("http://someUrl/someComponent")]
public ISomeComponent SomeService;
Its not actually an auto update, but the service could be always up to date. I am not sure if it works.. its just an idea :-)