After calling RegConnectRegistry(...) to open the registry on a remote machine, is it not possible to expand environment variables? I have looked at ExpandEnvironmentStrings and ExpandEnvironmentStringsForUser, but that only appears to be useful on the local machine. I think it must be possible considering that RegistryKey.GetValue() in .NET does expand the variables after calling RegistryKey.OpenRemoteBaseKey(), but I need to do this outside of .NET.
Any ideas?
Given that the environment variables running in a given process is based on the currently logged on user, how would you determine the set of environment variables that would be active on the remote machine?
Even if you could read that information (it's in the registry after all), what would you do about processes that change their environment?
Related
We use Pivotal Cloud Foundry's YML file to set up the environment. Everything is fine. According to DEVOPS if we have to modify/create an environment variable, we have to modify YML and push the app again. I am wondering if it is possible to modify/create an environment variable while the PCF app is running. It will be really cool if it can be done without having to redeploy the app. If it can't be done, is it because of Java's way of handling the environment?
Thanks
Can we change/modify the environment in PCF (Pivotal Cloud Foundy) at Runtime?
Yes and no.
You can modify environment variables associated with an application while the application is running using the cf set-env (to set or update) and cf unset-env (to delete).
This will update the environment variable in Cloud Controller at the time you run the command. However, this will not update the environment variable inside of a running application container. In order for your application to see the change that you made, you must cf restart, cf restage or cf push.
This has nothing to do with language specifics (i.e. it doesn't matter what language you're using). It is a requirement because the container where your application is running gets created with a fixed set of environment variables. When those change, the container must be recreated. That said, even if the container could be changed at runtime, in Linux a process' environment variables cannot be updated externally at runtime either (there are technically some ways to do this, but it's really unlikely you'd do this in practice). The process itself should be restarted for environment variables to change.
If you want to have your configuration update at runtime, you can look at something like Spring Cloud Config server & its refresh capabilities. That said, it turns out that most applications and frameworks assume configuration is read once while the app is starting up, so your application would need to support changing the configuration you want to change at runtime as well.
In Google shell which is a part of Google cloud, I set environment variable GOOGLE_APPLICATION_CREDENTIALS because It is need it for PHP NLP project [info: https://cloud.google.com/natural-language/docs/quickstart-client-libraries#client-libraries-install-php]. My project worked fine, but I notice that variable GOOGLE_APPLICATION_CREDENTIALS lasts on my sistem only one day. This is my third time that I am setting it. My project doesn't work when I am missing required variable. Am I doing something wrong?
EDIT:
It is default OS (Debian) when you create new App on Google App engine.
When I type help in Google shell I get info with:
Your 5GB home directory will persist across sessions, but the VM is ephemeral and will be reset
approximately 20 minutes after your session ends. No system-wide change will persist beyond that.
You are completely right, Cloud Shell is running on an ephemeral instance that resets some minutes after the session has ended, reason why you are losing the content of the environment variable you mentioned.
The documentation about limitations in Cloud Shell clearly states that it is intended for interactive use only, and any non-interactive session or intensive usage can be automatically terminated with (or without) a warning.
Therefore, and understanding from your question that you have a background script that is working with Cloud Natural Language, I would strongly advise you to move to a "real" instance of Compute Engine, in which you will have much more control about what is happening. This will allow more flexibility and you will be able to use a bigger machine type, given that Cloud Shell runs on a g1-small GCE instance which, in general, is not enough to run an application. Also, depending on your use case, you may even consider App Engine.
That being said, I have found that when constructing the LanguageClient instance, you may also not use Application Default Credentials and, instead, use the keyFile or keyFilePath variables (explained in the PHP Client Library reference) to pass the path to the JSON key directly to your code, instead of reading it from the environment variable.
Lets assume you are using Linux, make sure that:
The system is not being restarted, and if it is, make sure to set the environment variables accordingly (see how to set permantent environment variables)
I'm using AWS AppStream to stream a legacy .NET client. The app requires a parameter to start up correctly, which it gets via SessionContext passed into the create_streaming_url API call. I'd like to test this interaction locally without having to redeploy my app for every debug iteration as that takes well over half an hour. According to the AWS AppStream Docs session-context is stored in an environment variable that is only accessible via the AWS provided SessionContextRetriever.exe .NET application. The docs list the environment var as AppStream_Session_Context. I've tried setting this env var and running SessionContextRetriever.exe with no success. There is no documentation that I can find for SessionContextRetriever.exe but there's obviously something I'm missing here. Anybody have any experience with AppStream and session context?
The executable they provide doesn't come with a license, so I have to presume that it's copyrighted and licensed restrictively etc. So de-compiling it would be not be a good idea. But if somebody were to do such a thing, I would expect them to find something like
Console.Write(Environment.GetEnvironmentVariable("APPSTREAM_SESSION_CONTEXT", EnvironmentVariableTarget.Machine));
So I suggest that you try setting the environment variable at the system level for testing. That is, setting it in a script won't be visible to this executable because it's not looking at your current terminal session.
Setting the environment variable at the system level (using the Windows "Edit system environment variables) I see the output from this executable.
Run PS as Administrator:
PS C:\Users\Public\Apps> setx -m AppStream_Session_Context "Value"
PS C:\Users\Public\Apps> .\SessionContextRetriever.exe
Value
I have a Java application, using a jvm variable. Normally, I set it using a command like
APP_HOME="-DAPP_HOME=$CATALINA_HOME/myapp"
in order to point to the correct folder within my application structure on Tomcat.
Now I am trying to deploy my application to the MicroCloud virtual machine. Once deployed, I use the command
vmc env-add myapp APP_HOME="-DAPP_HOME=$HOME/myapp
to set my variable. But the problem is that the variable is set as a shell variable and not JVM variable. When I use System.getenv(); I can see that my variable is set, but when I use System.getProperty("APP_HOME") the variable is null.
Anyone had experience with this and could recommend what to do set it as a JVM variable on CF?
p.s.
I read all the existing topics on the CloudFoundry Q&A and here on stackoverflow, but I do not see an answer to this problem...
Thank you in advance!
What about
vmc env-add myapp JAVA_OPTS="-DAPP_HOME=$HOME/myapp"
(i.e. pass -DAPP_HOME as a property to the JVM)
However, why are you trying to do this - and why is it such a bad idea just to grab the value using getenv instead of looking for a system Property?
I'm trying to retrieve the path of the profiles directory across various versions of Windows. In older versions that might be [drive]:\Documents and Settings, on newer ones it's [drive]:\Users. There are several ways to do this locally without a problem, however I need to find the path on a remote machine that I've connected to.
Remote Registry is enabled.
I have an impersonation token and can successfully gather information from the remote host via the Net API, etc.
I have access to the administrative share, and therefore all the files on the remote drive.
Here's a list of other important caveats.
It's a C++ project.
It doesn't seem to be possible for GetProfilesDirectory or GetUserProfileDirectory to operate in a remote context. If I'm wrong about this please let me know but in all my experiments the function has returned something from the local machine.
I can't use WMI, we tried many times to integrate WMI functionality into our project and it just didn't work.
I would prefer to do as little "screen scraping" as possible. If you have an idea that doesn't involve reading from some text file and parsing the result, I'd love to hear it. But I'd appreciate any useful answer really.
The profile directory information in the registry don't seem to be useful because it contains environment variables, and like GetProfilesDirectory, the environment variable expansion function does not seem designed for work with remote hosts. This means that the solution wouldn't work if I was making the call from a newer Windows machine to an older Windows machine or vice versa.
The solution should be general enough to work between hosts that might be running any version of Windows from Windows Server 2003 to Windows 7.
Thanks in advance for whatever ideas you might have. Ideally I'd just like to be able to force GetProfilesDirectory to operate on the remote host so if you know how to do that I'll love you forever.
If you have access to the remote registry, you should be able to look at the key where the profile directory and the profile list is kept:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList