How to clear phpFastCache when path set to /tmp/ - caching

I'm using phpFastCache in a frontend-application, setting the path to the server's "/tmp/" directory:
phpFastCache::setup('path',"/tmp/");
I do not want to use phpFastCache's automatically found cache-directory, because it clutters my home directory with an extra directoy for every domain through which users are reaching the application (several are connected).
In the backend I would like to display cache-statistics and be able to clear the cache. This doesn't work anymore, now that I have set /tmp/ as the cache path. Statistics show up empty and the cache is not cleared. I did configure the cache-directoy to the same "/tmp/" in the backend-application as well.
How can phpFastCache be configured to be able to achieve this?

After looking at the phpFastCache-code, I'm able to answer my own question:
To achieve what I wanted (have only ONE cache-directory, regardless of domain used; be able to list statistics and clear cache from a separate application) I had to make two config-settings:
phpFastCache::setup('path', '/path-to-my-home-dir');
phpFastCache::setup('securityKey', 'phpfastcache');
I'm setting these identically in both my frontend- and backend-applications.
This will make phpFastCache use /path-to-my-home-dir/phpfastcache as its only cache-directory.
Had I not set the 'securityKey', phpFastCache would have generated one from the current domain (in most cases), therefore my backend application would have only "seen" that part of the cache residing in the directory for the currently used domain.

Related

existdb: identify database server

We have a number of (developer) existDb database servers, and some staging/production servers.
Each have their own configuration, that are slightly different.
We need to select which configuration to load and use in queries.
The configuration is to be stored in an XML file within the repository.
However, when syncing the content of the servers, a single burnt-in XML file is not sufficient, since it is overwritten during copying from the other server.
For this, we need the physical name of the actual database server.
The only function found, request:get-server-name that is not quite stable since a single eXist server can be accessed through a number of various (localhost, intranet or external) URLs. However, that leads to unnecessary duplication of the configuration, one for each external URL...
(Accessing some local files in the file system is not secure and not fast.)
How to get the physical name of the existDb server from XQuery?
I m sorry but I don't fully understand your question, are you talking about exist's default conf.xml or your own configuration file that you need to store in a VCS repo? Should the xquery be executed on one instance and trigger an event in all others, or just some, or...? Without some code it is difficult to see why and when something gets overwritten.
you could try console:jmx-token which does not vary depending on URL (at least it shouldn't)
Also you might find it much easier to use a docker based approach. Either with multiple instances coordinated via docker-compose or to keep the individual configs from not interfering with each other when moving from dev to staging to production https://github.com/duncdrum/exist-docker
If I understand correctly, you basically want to be able to get the hostname or the IP address of a server from XQuery. If the functions in the XQuery Request module are not doing as you wish, then another option would be to set a Java System Property when starting eXist-db. This system property could be the internal DNS name or IP of your server, for example: -Dour-server-name=server1.mydomain.com
From XQuery you could then read that Java System property using util:system-property("our-server-name").

How do I disable Symfony from writing _sess files to my /tmp directory

I am new to symfony and am responsible for a site that I didn't build. For some reason the site is on a live server but running in dev mode. - Im not sure why??
That aside - The website keeps writing _sess files to my /tmp directory. The contents of each _sess file is exactly the same. See below:
_symfony2|a:3:{s:10:"attributes";a:0:{}s:7:"flashes";a:0:{}s:6:"locale";s:2:"en";}
Do I really need all of these files? Can anyone suggest a way of disabling this feature?
Thanks in advance
The default session storage of Symfony2 writes the session information to file(s). The location these files are written to is determined by the config parameter framework.session.save_path. The default value for this is %kernel.cache.dir%/sessions. This means that in a default installation of symfony the session files would be written to the cache directory for the environment.
However, this can be a problem as the cache directory has to be cleared each time an app is deployed, thus logging all the users out. Therefore presumably your app has been configured (most likely in config.yml) to store the session files in /tmp.
As I understand it, sessions that have expired should be garbage-collected at some point. Symfony also has some config params that affect this - see the FrameworkBundle Configuration. I don't know how much traffic your website has but obviously you do need the session files for active sessions. If you think you have a lot of expired sessions you could try tweaking the gc config params.
Alternatively, if having the session files in /tmp is specifically the problem you could relocate them (by changing the value of the framework.session.save_path) or use PDOSessionHandler to store sessions in the database.
I have this problem with symfony 1.4.20 on a web site I inherited.
It is writing files to
/var/lib/php/sessions
every second, until the server runs out of iNodes.
I've tried changing settings in settings.yml. app.yml and PHP session variables.
Nothing sees to be working though, the only way I can stop it is to change the ownership of /var/lib/php/sessions to root and that prevents any session files being created.

WindowsAzure: Is it possible to set directory permissions within the web.config?

A PHP scriptof mine wants to write into a log folder, the resulting error is:
Unable to open the log file "E:\approot\framework\log/dev.log" for writing.
When I set the writing permissions for the WebRole User RD001... manually it works fine.
Now I want to set the folder permissions automatically. Is there an easy way to get it done?
Please note that I'm very new to IIS and the stuff around, I would appreciate precise answers, thx.
Short/Technical Response:
You could probably set permissions on a particular folder using full-trust and a startup taks. However, you'd need to account for a stateless OS and changing drive letters (possible, not likely) in this script, which would make it difficult. Also, local storage is not persisted, so you'd have no way to ensure this data stayed in the case of a reboot.
Recommendation: Don't write local, read below ...
EDIT: Got to thinking about this, and while I still recommend against this, there is a 3rd option: You can allocate local storage in the service config, then access it from PHP using a dll reference, then you will have access to that folder. Please remember local storage is not persisted, so it's gone during a reboot.
Service Config for local:
http://blogs.mscommunity.net/blogs/dadamec/archive/2008/12/11/azure-reading-and-writing-with-localstorage.aspx
Accessing config from php:
http://phpazure.codeplex.com/discussions/64334?ProjectName=phpazure
Long / Detailed Response:
In Azure, you really are encouraged to approach things as a platform and not as "software on a server". What I mean there is that ideas such as "write something to a local log file" are somewhat incompatible with the cloud "idea". Depending on your usage, you could (and should) convert this script to output this data to some cloud-based or external storage, vs just placing it on the disk.
I would suggest modifying this script to leverage the PHP Azure SDK and write these log entries out to table or blob storage in Azure. If this sounds good, please provide the PHP and I can give an exact example.
The main reason for that (besides pushing the cloud idea) is that in Azure, you cannot assume the host machine ("role instance") will maintain an OS state, so while you can set some things such as folder permissions, you can't rely on them sticking that way. You have no real way to guarantee those permissions won't be reset when the fabric has to update your role and react to some lower level problem. For example, a hard-drive cage on the rack where your current instance lives could fail. If the failure were bad enough, the Fabric controller would need to rebuild your instance. When that happens, your code is moved to an entirely different server, so the need would arise to re-set those permissions. Also, depending on the changes, the E:\ could all of a sudden need to be the F:\ or X:\ drive and you wouldn't know.
Its much better to pretend (at some level) that your application is running "in Azure" and not "on a server in azure", so you make no assumptions about the hosting environment. So anything you need outside of your code (data, logs, audits, etc) should be stored somewhere you can control (Azure Storage, external call-out, etc)

Magento - Magento Cache

I am using memcache.
I want to understand what is stored in Magento cache and how?
Do magento stores cache variable with website scope or store scope?
I have googled and greped the code but couldnt conclude anything,
Please if someone can direct me to correct links and path
Thanks & Regards,
Saurabh
If you go to the Cache Management section of the admin area you can see what it caches (configuration, layout configuration, block html output, translations, eav types, etc). I am no expert on Magento's caching mechanisms but here are a few random tidbits that might be helpful (maybe). (Also note that I am only familiar with Magento 1.3.x, not 1.4.x so things could have changed).
The caching is actually stored in the var/cache directory. There are a ton of directories in there (mage--0, mage--1, mage--2) and each directory has the cache files. Do a ls var/cache/mage*/* to see all the files.
Configuration - This source for the configuration is varied. Your app/etc/local.xml, and all of the config.xml files (that are in each module's etc dir) are combined together to make one big configuration object. Then Magento reads from the core_config_data table to update the configuration object. Then the configuration is written to a cache file so that next time a request is made it doesn't need to open a ton of config files and hit the database. Somehow this info gets stored in a bunch of files under var/cache. For some insight do a ls var/cache/mage*/*CONF*.
Layout - This is a lot like the configuration... there are a bunch of xml files in the app/design/frontendOrAdminhtml/yournamespace/layout/ directory and all these are merged into one layout configuration object, then cached in the cache directory.
Block HTML - The actual html generated by a block is cached. Each block is able to decide how long it is going to be cached.
Lastly, to (not really) answer your question about if the cache is per website or store, I can't really say since I haven't had the need to setup a multi-website/multi-store shop yet. It looks like there may be some store/website-specific files, but I can't see that they are really organized in a logical way. For example, in one of my instances I see a var/cache/mage--f/mage---LAYOUT_FRONTEND_STORE0_DEFAULT_BLANK_SEO file and a var/cache/mage--f/mage---LAYOUT_FRONTEND_STORE1_DEFAULT_BLANK_SEO... but then again, I only have one store configured and those two files have the same contents. Good luck with that!
You could also use some of the very great memcached analysis and reporting tools available
http://code.google.com/p/memcached/wiki/Tools
The best solution I have come up with is to use a two level cache.
Consult app/etc/local.xml.additional to see how to put memcached server nodes in there. Note that within the <servers> tag you will have to have tags like <server1> and <server2> encapsulating each memcached node's settings.
<cache>
<backend>memcached</backend>
<slow_backend>database</slow_backend>
</cache>
In this way all cache is shared.
To clear it the way I do it is to:
1. shut down apache
2. connect to mysql and connect to the magento db and run truncate core_cache; truncate core_cache_tag.
3. I then bounce the memcached nodes.
4. I restart apache but I keep it out of the load balancer until I have hit it at least once to generate the APC opcode cache. Otherwise the load can shot up through the roof.
This all seems extreme but I have found it works for me. Clearing cache using the backend is REALLY slow. I have around 100k entries in the core_cache table and close to 1 million entries in core_cache_tag. If I don't do it this way sometimes I get strange behavior.
Your Memcache configuration in ./app/etc/local/xml will dictate what Memcache is actually caching.
If you are only using a the single-level cache (without ), then Magento will store its cache (in its entirety) in Memcache.
HOWEVER without the slow_backend defined - it is caching content, without cache_tags - ie. without the ability to differentiate cache items
Eg. configuration, block, layouts, translations etc.
So, without the defined, you cannot refresh caches individually, in-fact, you'll almost always have to rely on "Flush Cache Storage" to actually see updates take effect.
We wrote a nice article here which covers your very issue - http://www.sonassi.com/knowledge-base/magento-knowledge-base/what-is-memcache-actually-caching-in-magento/
Memcached is a distributed memory caching system. It speeds up websites having large dynamic databases by storing database objects in Dynamic Memory to reduce the pressure on a server whenever an external data source requests a read. A Memcached layer reduces the number of times database requests are made.
The caching is actually stored in the var/cache directory. There are a ton of directories in there (mage--0, mage--1, mage--2) and each directory has the cache files. Do a ls var/cache/mage*/* to see all the files.
Configure Memcache Magento 2
Magento 2 also supports Memcached for caching objects but it isn’t enabled by default. You need to make simple changes to the $Magento2Root/app/etc/env.php file to enable it.
In env.php, you will see a large number of PHP arrays with different settings and configurations. Open the file in your favorite code editor and locate the following code:
array (
session' =>
'save' => 'files',
),
Modify this chunk as:
'session' =>
array (
'save' => 'memcached',
'save_path' => '<memcache ip or host>:<memcache port>'
),
Note that the default value for memcache ip is 127.0.0.1:11211. Similarly, the default value for memcache port is 11211.
For complete manual please look into it:
https://www.cloudways.com/blog/magento-2-memcached/
https://devdocs.magento.com/guides/v2.4/config-guide/memcache/memcache_magento.html

What is my Eclipse-RCP application storing in $HOME/.eclipse, and how do I prevent it?

When I run my Eclipse RCP application, it creates a whole lot of directories in my $HOME/.eclipse directory. What is this?
I don't want the files there, how can I hinder them from getting there? The rational for this: the application must run very clean and only leave files at one specific location (not $HOME/.eclipse).
I'd figured it was controlled by osgi.instance.area so tried to set this to different values (a directory, #none, #noDfault etc...) but can't stop the application from creating directories in $HOME/.eclipse. -data and other arguments works as expected.
On my system the only thing that is stored in .eclipse is the Equinox Secure Storage. Here is the blurb on the doc page for that:
By default, secure storage is located in your home directory. On Windows that typically resolves to "C:\Documents and Settings\.eclipse\org.eclipse.equinox.security". This location is selected to allow multiple Eclipse-based applications to share the same secure storage.
If you would like to modify the location of the default secure storage, you can use the "-eclipse.keyring " runtime option. The is a path to the file which is used to persist the secure storage data.
Here is the online reference.

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