Develop Reference

How to set password for snowchange

Trying to run snowchange as explained in the README.
python snowchange/cli.py -a SNOWFLAKE_ACCOUNT -u SNOWFLAKE_USER -r SNOWFLAKE_ROLE -w SNOWFLAKE_WAREHOUSE -d SNOWFLAKE_DATABASE --create-change-history-table
However I do not understand how to set the environment variable for the password.
Tried: Setting the password in an interactive python. It doesn't work as the variable is set only for the current process and when going out of the python command line to execute the command, I don't have access anymore.

You can pass by Powershell command as below
setx SNOWFLAKE_PASSWORD passwordvalue
But make sure when you have a $ sign in password, it can't work from client, you have to add it from GUI User-specific windows envs.
Ref: https://rajivgupta780184.medium.com/database-change-management-tool-schemachange-with-snowflake-overview-b62dec744e0a

sbin/start-stop-daemon not able to start python - ubuntu docker container

I have a simple python script which I want to start a daemon-service in background in docker container
/sbin/start-stop-daemon --start --user root --make-pidfile --pidfile /var/lock/subsys/my-application.pid --exec 'python /opt/app/uc/monitor/bin/my-application.py'
when I execute this command in a shell I get
/sbin/start-stop-daemon: unable to stat //python /opt/app/uc/monitor/bin/my-application.py (No such file or directory)
However when execute just the below command in shell it works
python /opt/app/uc/monitor/bin/my-application.py
I'm sure the python is installed and all the links have been setup.
Thanks for the help

That error message implies that start-stop-daemon is looking for a file to open (the stat operation is a check before it opens the file) and treating your 'python ... ' argument as if it was a file.
See this example which confirms this. You may need to read the man page for start-stop-daemon, for your Ubuntu version, to check what a valid command would be for your setup.
Simplest solution is probably to create a shell script (say /opt/app/uc/monitor/bin/run-my-application.sh), and put this into it:
#!/bin/bash
python /opt/app/uc/monitor/bin/my-application.py
Be sure to do chmod +x on this file. If python is not found, use which python to find the path to python and use that in the script.
Now try:
/sbin/start-stop-daemon --start --user root --make-pidfile --pidfile /var/lock/subsys/my-application.pid --exec '/opt/app/uc/monitor/bin/run-my-application.sh'

Executing shell command using docker-py

I'm trying to run a shell command with docker-py on an already-running container, but get an error:
exec: "export": executable file not found in $PATH
here's how I wrote the script:
exe = client.exec_create(container=my_container, cmd='export MYENV=1')
res = client.exec_start(exec_id=exe)
so my question is how can I run a shell command (inside the container) using docker-py?

You did it quite right. But you confused shell commands with linux executables. exec_create and and exec_start are all about running executables. Like for example bash. export in your example is a shell command. You can only use it in a shell like bash running inside the container.
Additionally what you are trying to achieve (setting a environment variable) is not going to work. As soon as your exec finishes (where you set the env var) the exec process will finish and its environment is been torn down.
You can only create global container environment variables upon creation of a container. If you want to change the env vars, you have to tear down the container and recreate it with your new vars. As you probably know, all data in the container is lost upon a remove unless you use volumes to store your data. Reconnect the volumes on container creation.
That said your example was nearly correct. This should work and create an empty /somefile.
exe = client.exec_create(container=my_container, cmd=['touch', '/somefile'])
res = client.exec_start(exec_id=exe)
To execute shell commands, use this example. It calls sh and tells it to run the interpreter on the given command string (-c)
exe = client.exec_create(container=my_container,
cmd=['/bin/sh', '-c', 'touch /somefile && mv /somefile /bla'])
res = client.exec_start(exec_id=exe)

For actually , when execute cmd docker exec in docker container export MYENV=1. It will fail and report this error
exec: "export": executable file not found in $PATH
Because export is a shell builtin, could run the cmd in shell.
whereis export
type export
can not find export in /usr/bin/ or somewhere else.
There is some ways to pass through this problem.
case1: use -c parameter
/bin/bash -c 'export MYENV=1 ; /bin/bash'
case2: append export cmds to a rcfile, then use this file.
echo "exprot MYENV=1" >> <some_file_path> ; /bin/bash --rcfile <some_file_path>
case3: open a terminal, then enter the cmds to export env parameters , then open a new terminal, the env parameters will work.
/bin/bash
exprot MYENV=1
/bin/bash # open a new terminal

Writing Shell Commands to VirtualEnv?

Is there a way I can write commands to a virtual environment after it's been activated? For example lets say I have a Python or Bash script which does some, stuff i.e.
Make a virtualenv
Activates it.
Executes the commands to the shell of the newly created virtual environment?
For example I am doing something like this:
activate_this = subprocess.call("/bin/bash --rcfile " + "/home/" + os.getlogin() + "/mission-control/venv/bin/activate", shell=True)
process = execfile(activate_this, dict(__file__=activate_this))
process.communicate(subprocess.call(virtualenv.create_bootstrap_script(textwrap.dedent
("""
import subprocess
subprocess.call("pip install -r " + os.environ['VIRTUAL_ENV'] + "/requirements.txt", shell=True)
"""
))))
I would like to install the requirements.txt file after I activate the environment however I can't get the subprocess module to communicate with the shell after the virtual environment is created. I think it might have to do with me creating a new virtual environment via execfile, which therefore is creating a new process.
Also I know shell=True is bad practice but as of right now I am not concerned with the possibility of unsanitized input.

. "$VIRTUAL_ENV/bin/activate"
pip install -r "$VIRTUAL_ENV/requirements.txt"

First of all, thanks to #Ryne Everett for the help. So I solved this by just ditching the Python solution and creating a Bash file which I call from subprocess in my Python script. The subprocess call executes the Bash file which handles creating and executing within the virtualenv. I am not sure how to solve this using just Python. I am sure there is a way but this seems like a simpler solution. The Bash script is the following:
#!/bin/bash
MISSION_CONTROL="$PWD"
if [ ! -d "$MISSION_CONTROL/venv" ]; then
virtualenv $MISSION_CONTROL/venv --no-site-packages
echo "Welcome to Mission Control..."
/bin/bash --rcfile $MISSION_CONTROL/venv/bin/activate
fi
if [ -d "$MISSION_CONTROL/venv" ]; then
pip install -r $MISSION_CONTROL/requirements.txt
fi
EDIT: This may also be useful for people who are trying to do something similiar: How to source virtualenv activate in a Bash script

Running sudo command via CGI (Python)

I am writing a test suite for a web application using Selenium.
In the course of which I need to test behaviour of the app in case a certain service is running or not.
I wanted to create a cgi call to a Python script turning that service on and off.
I know that the cgi call is in the context of the webserver (Apache) however thought that issuing sudo calls like so:
import subprocess
import os
command = 'sudo -S launchctl unload /Library/LaunchAgents/com.my.daemon.plist'
pwd = 'pwd123'
test1 = subprocess.Popen( command, shell=True, stdin=subprocess.PIPE)
test1.communicate(input=pwd)
test2 = os.system( 'echo %s|%s' % (pwd,command) )
would do the trick, well they don't I get return code 256.
What can I do to have this call be executed w/o touching the context in which Apache runs?
As for security: this will only run on a test machine.

The user that Apache runs as needs to be in the /etc/sudoers file, or belong to the sudo group, which I guess it usually doesn't. You also need to make it not ask for a password, which is configured in /etc/sudoers
For Ubuntu, check these out: https://askubuntu.com/questions/7477/how-can-i-add-a-new-user-as-sudoer-using-the-command-line
https://askubuntu.com/questions/147241/execute-sudo-without-password

It could potentially be a pathing issue..
Have you tried writing out the full path like this:
command = '/usr/bin/sudo -S launchctl unload /Library/LaunchAgents/com.my.daemon.plist'

command should be a list, not a string. Try with:
command = ['sudo', '-S', 'launchctl', 'unload', '/Library/LaunchAgents/com.my.daemon.plist']

Cant run sudo this way -- sudo needs a controlling terminal to run.