Looking at the documentation for SBWatchpoint at http://lldb.llvm.org/python_reference/index.html, I do not see a method for assigning a python callback function for when a watchpoint is triggered.
Is there a way to do this with the Python API?
There is a
watchpoint command add
command that supports doing that
watchpoint command add [-e <boolean>] [-s <none>] [-F <python-function>] <watchpt-id>
If you have an SBWatchpoint, you can query for its ID, and then craft an appropriate command line to pass down to SBDebugger.HandleCommand
You will need your Python module to contain the script function you want executed, and pass it by qualified name on the command line. For instance, if you have
# myfile.py
def callback(wp_no):
# stuff
# more stuff
mywatchpoint = ...
debugger.HandleCommand("watchpoint command add -F myfile.callback %s" % mywatchpoint.GetID())
would be the way to tell LLDB about your callback
Currently, there is no way to pass Python functions directly to LLDB API calls.
There is no reason why that is impossible, but it is a little tricky to get right in a world where multiple scripting languages could coexist, and given the lack of a viable alternative strategy, there's not much pressure to get it working.
Related
This question already has answers here:
When to wrap quotes around a shell variable?
(5 answers)
How to pass all arguments passed to my Bash script to a function of mine? [duplicate]
(7 answers)
Closed 3 years ago.
The problem:
I'm writing a program that performs actions in python based on links, and possibly expanding it to do things beyond that. This program is meant to be quickly used through bash. So, I'm using a custom function to do that.
function youtube() {python3 <youtube program path here> $1}
As for the python file; I'm using sys, os, and re in order to make it function. sys, in order to use both sys.exit() and var = sys.argv[<argNum>], the former in order to exit the program using custom exceptions, like error.searchError() or error.usageError(), and the later for actualling using the arguments from the command itself. os is just for os.system('{}'.format(<your command here>)). And re is for removing the spaces from the second argument, where my problem lies, and replacing them with '+', as per query = re.sub(' ', '+', query).
Now, as for the problem itself. As I mentioned before, the problem lies with the second bash argument, or sys.argv[2]. With sys.argv[0] being the python file, and sys.argv[1] being the option, in this case being -s.
sys.argv[2] is meant to be the actual youtube search query. But, according to whenever I use the command with all three arguments, youtube -s Hi this is a test., I get the following output, as per the custom error I made: No search query provided!. This only happens when python excepts an IndexError, which means that the program is not receiving the second argument from bash or zsh. What is actually supposed to happen, when the second arguments does exist, is:
os.system('open https://www.youtube.com/results?search_query=Hi+this+is+a+test.')
Which opens that link in my default browser. I have tried to add $2 to the custom function, and various ways of entering the second argument through the python source itself, including using a x = input('Search Query: ') statement. But that isn't optimal for what I'm doing.
The code:
The following is the source code for all the nonsense I just typed out.
The custom function:
function youtube() {python3 <python program path here> $1}
For those that have no idea what this means (i.e.; people that don't know much (or anything) about bash coding); The function method creates a bash object, in this case, youtube(). As for the code in the brackets ({}), this uses the function python3, which just pushes the program in argument 0 to the python 3.x interpreter, to open <python program path here>, which is a placeholder for the actual path of the program. As for $1, this is a variable that always equals the text inputted after the function name.
The custom errors:
class error:
def usageError():
usageError = '''Usage: youtube [-s] [<search_query>]
Help: Performs actions related to https://www.youtube.com
Options:
-s Opens https://www.youtube.com/results?search_query=<your query here>'''
print(usageError)
sys.exit()
def searchError():
searchError = 'No search query provided!'
print(searchError)
sys.exit()
Is this irrelevant? I'm not sure, but I'm putting it in anyway! Now, if you don't understand it, the following should explain it.
The error class contains all of the customs errors for this program, ok? Ok, so you get that, but what do these functions do? usageError is raised when argument 1 simply doesn't exist, and prints the usage information to the terminal. Then sys.exit()s the program, basically the equivalent of hitting Alt+f4 in video game. searchError, on the other hand, only happens if argument 2 doesn't exist, meaning there is no search query. It then tells you that you're stupid, and will need to actually enter your query for it to work.
Well, maybe not that exactly, but you get the point.
The Juicy Bits:
option = ''
try: option = sys.argv[1];
except IndexError: raise error.usageError()
if option == '-s':
try:
query = sys.argv[2]
query = re.sub(' ', '+', query)
os.system('open https://www.youtube.com/results?search_query={}'.format(query))
except IndexError: raise error.searchError();
Just to explain; First, the program creates the variable option and then sets it to an empty string. Then, it tries to set option to argument 1, or the option. If argument 1 doesn't exist, it raises the error error.usageError, as explained in The Custom Errors. After that, the program tries to create the variable query, and set it to argument 2, then replace all of the spaces in query with '+' signs. If all of that succeeds to happen, it then loads up the youtube search in your default browser. If not, it raises the error error.searchError().
The Edits
Edit 1. The error was in The Custom Function. Where I should have had an $#, I had an $1. As Jeshurun Roach explains in his answer, $1 only holds the argument 1, and no other arguments. While $# contains all variables.
function youtube() {python3 <python program path here> $#}
$1 refers to the first argument passed into the function. in bash, spaces delimit arguments. so in your example youtube -s Hi this is a test.,
$1 is -s,
$2 is Hi,
$3 is this etc...
What you're looking for is the $# symbol. This value stands for all the arguments.
But just plugging in $# instead of $1 won't fix all your problems. in your python script, each argument will be broken up again by spaces, just like the bash function.
To fix this, you can put quotes around the text after the flag like so: youtube -s 'Hi this is a test.'.
If you call your program like this: youtube -s something cool, then sys.argv[2] is going to be "something".
I'd suggest wrapping your query in quotes. For example youtube -s "something cool".
This question already has answers here:
Display help message with Python argparse when script is called without any arguments
(18 answers)
Closed 3 years ago.
I am writting a new script and would like for the -h or --help argument to be called by default when the script is called without any parameters. So for example if someone calls command_line_utility.py then I want it to print the output you would get with command_line_utility.py -h.
I have dug around in the docs and looked at some examples, but all of them were specifying default argument values and not actually having arg parse call a default argument.
# Setting up Main Argument Parser
main_parser = argparse.ArgumentParser(description="A set of python web utility scripts")
main_parser.add_argument("-v",'--version', action='version', version='kuws V0.0.1')
# Setting up the main subparser
subparsers = main_parser.add_subparsers(help="Available commands found below, for more info on a command use: python command_line_utility.py <command> -h or kuws <command> -h")
"""Code below handles 'redirects' command in the main script
i.e. >python command_line_utility.py redirects or kuws redirects
"""
redirects_parser = subparsers.add_parser('redirects', argument_default='-u',
help='Allows you to trace redirects and get other information')
redirects_parser.add_argument('-u', "--url",
help='usage: python main.py redirects -u <url>; Lets you see the trace for a url', nargs='?', dest="trace_url")
As it stands when I run the file nothing actually gets printed to the command line. No help text or errors or anything.
I'm afraid argparse doesn't have any built-in support for this, but you can identify this situation and print the help message:
import sys
if len(sys.argv)==1:
parser.print_help(sys.stderr)
sys.exit(1)
Checking that len(sys.argv)==1 and in that case calling the print_help method of the parser as described in this answer to a similar question is a possible way to print the help message defined in the parser when no arguments are given.
When using subparsers, a common scheme is using set_defaults(func=<function to be called>) and then calling this function (as explained in sub-commands).
You can simply define a first set_defaults(func=help) at first that will be overwritten with the functions of your command.
Note that you can also make the command required when you declare your subparsers (add_subparsers(..., required='True')) and thus, when the user invokes without a command, she will get an error with the usage.
when I issue git with tab , it can auto-complete with a list, I want to write a test.py, when I type test.py followed with tab, it can auto-complete with a given list defined in test.py, is it possible ?
$ git [tab]
add branch column fetch help mv reflog revert stash
am bundle commit filter-branch imap-send name-rev relink rm status
annotate checkout config format-patch init notes remote send-email submodule
apply cherry credential fsck instaweb p4 repack shortlog subtree
archive cherry-pick describe gc log pull replace show tag
bisect clean diff get-tar-commit-id merge push request-pull show-branch whatchanged
blame clone difftool grep mergetool rebase reset stage
The method you are looking for is: readline.set_completer . This method interacts with the readline of the bash shell. It's simple to implement. Examples: https://pymotw.com/2/readline/
That's not a feature of the git binary itself, it's a bash completion 'hack' and as such has nothing to do with Python per-se, but since you've tagged it as such let's add a little twist. Let's say we create a script aware of its acceptable arguments - test.py:
#!/usr/bin/env python
import sys
# let's define some sample functions to be called on passed arguments
def f1():
print("F1 called!")
def f2():
print("F2 called!")
def f3():
print("F3 called!")
def f_invalid(): # a simple invalid placeholder function
print("Invalid command!")
def f_list(): # a function to list all valid arguments
print(" ".join(sorted(arguments.keys())))
if __name__ == "__main__": # make sure we're running this as a script
arguments = { # a simple argument map, use argparse or similar in a real world use
"arg1": f1,
"arg2": f2,
"arg3": f3,
"list_arguments": f_list
}
if len(sys.argv) > 1:
for arg in sys.argv[1:]: # loop through all arguments
arguments.get(arg, f_invalid)() # call the mapped or invalid function
else:
print("At least one argument required!")
NOTE: Make sure you add an executable flag to the script (chmod +x test.py) so its shebang is used for executing instead of providing it as an argument to the Python interpreter.
Apart from all the boilerplate, the important argument is list_arguments - it lists all available arguments to this script and we'll use this output in our bash completion script to instruct bash how to auto-complete. To do so, create another script, let's call it test-completion.bash:
#!/usr/bin/env bash
SCRIPT_NAME=test.py
SCRIPT_PATH=/path/to/your/script
_complete_script()
{
local cursor options
options=$(${SCRIPT_PATH}/${SCRIPT_NAME} list_arguments)
cursor="${COMP_WORDS[COMP_CWORD]}"
COMPREPLY=( $(compgen -W "${options}" -- ${cursor}) )
return 0
}
complete -F _complete_script ${SCRIPT_NAME}
What it does is essentially adding to complete the _complete_script function to be called whenever a completion over test.py is invoked. The _complete_script function itself first calls list_arguments on test.py to retrieve its acceptable arguments, and then uses compgen to create a required structure for complete to be able to print it out.
To test, all you need is to source this script as:
source test-completion.bash
And then your bash will behave as:
$ ./test.py [tab]
arg1 arg2 arg3 list_arguments
And what's more, it's completely controllable from your Python script - whatever gets printed as a list on list_arguments command is what will be shown as auto-completion help.
To make the change permanent, you can simply add the source line to your .bashrc, or if you want more structured solution you can follow the guidelines for your OS. There are a couple of ways described on the git-flow-completion page for example. Of course, this assumes you actually have bash-autocomplete installed and enabled on your system, but your git autocompletion wouldn't work if you didn't.
Speaking of git autocompletion, you can see how it's implemented by checking git-completion.bash source - a word of warning, it's not for the fainthearted.
I am invoking Robot Framework on a folder with a command like following:
robot --name MyTestSuite --variablefile lib/global_variables.py --variable TARGET_TYPE:FOO --variable IMAGE_TYPE:BAR --prerunmodifier MyCustomModifier.py ./tests
MyCustomModifier.py contains a simple SuiteVisitor class, which includes/excludes tags and does a few other things based on some of the variable values set.
How do I access TARGET_TYPE and IMAGE_TYPE in that class? The method shown here does not work, because I want access to the variables before tests start executing, and therefore I get a RobotNotRunningError with message Cannot access execution context.
After finding this issue report, I tried to downgrade to version 2.9.1 but nothing changed.
None of public API's seem to provide this information but debugging the main code does provide an alternative way of obtaining it. It has to be said that this example code will work with version 3.0.2, but may not work in the future as these are internal functions subject to change. That said, I do think that the approach will remain.
As Robot Framework is an application, it obtains the command line arguments through it's main function: run_cli (when running from command line). This function is filled with the arguments from the system itself and can be obtained throughout every python script via:
import sys
cli_args = sys.argv[1:]
Robot Framework has a function that interprets the commandline argument list and make it into a more readable object:
from robot.run import RobotFramework
import sys
options, arguments = RobotFramework().parse_arguments(sys.argv[1:])
The argument variable is a list where all the variables from the command line are added. An example:
arguments[0] = IMAGE_TYPE:BAR
This should allow you to access the information you need.
I am trying to write a custom step, that will run few commands, and return a pas or fail based on certain conditions.
So far I was able to subclass ShellCommand; so I can execute a shell command on the slave. Now the next step is to write something that will execute not only one shell command, but various ones, and will analyze the results of these commands and act accordingly.
Altho I've not been successful in this endeavor. So far I am only able to subclass ShellCommand; but this allow me to run just one command.
I have found that ShellCommand uses buildstep.remoteCommand and remoteShellCommand; but my attempts to subclass buildstep.BuildStep has been unsuccessful.
The objective that I want to accomplish is to run a finite amount of python or shell commands (without write a shell script and call it from python; I was able to accomplish that), and analyze the results coming from these operations, so I can dictate if a step pass or fail, and what is logged.
So far this is what I have:
class myclass(build step.BuildStep)
def __init__(self, **kwargs):
buildstep.BuildStep.__init__(self, **kwargs)
def start(self):
cmd=buildstep.RemoteShellCommand({'command':"ls -la"})
self.setupEnvironment(cmd)
d=self.runCommand(cmd)
return d
This will run, and I will get an error on the remoteShellCommand line, saying
exceptions.TypeError: __init__() takes at least 3 arguments (2 given)
I've tried with both remoteCommand and remoteShellCommand, and the result is the same.
Checking init for both, I can't see 3 arguments but just the command, so I am not really sure what is wrong. I even tried to use **kwargs but I get an error saying that kwarg is not defined (there was an example from a blog, that would use kwargs; so I tried and it didn't work anyway).
This is the original documentation for the remoteShellCommand:
[Original Buildbot API documentation][1]
Do you know where I could find an example that actually show me how to accomplish this, or at least how do you actually use remoteCommand/remoteShellCommand? The original docs are a mess, even google returns few results that are even more obscure than the original docs.
Any suggestion is welcome; I've been running in circles for the past 3 days, and have no idea about where to look next.
One way to have a shellcommand execute multiple commands is to pass it a script instead of a command as this example shows:
class CoverageReport(ShellCommand):
def __init__(self):
self.coverage_path = '/var/www/coverage'
command = '''rm -rf htmlcov
coverage html
cp htmlcov/* %s/''' % self.coverage_path
description = 'Generating coverage report'
workdir = 'build/python'
self.url = "https://XXXXXXXX/coverage"
ShellCommand.__init__(self, command=command, description=description, workdir=workdir)
This Shellcommand does three things:
remove old report
Generate a new report
Copy the report to the www folder
Returned value will be the one of equivalent bash script, you can probably play with bash to return whatever you want
The other option is to add multiple steps to your build