Re: Seeking Assistance with Python's IDLE for Blind Users
Jeff, there are a few specific programmer's resources for blind/VI programmers that might help more - I am myself a 100% blind programmer, and, would not necessarily recommend idol from our perspective, since most people use VS code, or things like edSharp or even pycharm, but, I am a user of NVDA, which is itself written in python, and not a jaws user, so you might do better to ask some of the other people in that context - general blind programmer's mailing list: https://www.freelists.org/list/program-l And, the pythonvis blind python programmer's mailing list: https://programmingforeveryone.groups.io/g/pythonvis But, besides that, I am a 100%/full-time python web-developer, who uses python for other things as well, and, besides VS code, edSharp programmer's text editor is still probably my code editor of choice. Jacob Kruger +2782 413 4791 "Resistance is futile!...Acceptance is versatile..." On 2024/11/11 00:28, Jeff via Python-list wrote: Dear Python Users Group, I am currently learning Python. I am blind and use the JAWS screen reader to assist me. I am trying to use Python's IDLE editor but find it quite challenging. When I move my cursor to a line of code, it reads out the letters or words from the line above, which makes it very difficult to edit the code accurately. I am reaching out to see if anyone knows how to configure IDLE to call out the letters or words that the cursor is actually on. Additionally, I have searched extensively online but have not been able to find any documentation specifically designed for blind users on how to effectively use Python's IDLE. Any guidance or resources you could provide would be greatly appreciated. Thank you for your assistance. Best regards, Jeff -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
On 12/11/2024 08:52, Loris Bennett via Python-list wrote:
Cameron Simpson writes:
Generally you should put a try/except around the smallest possible
piece of code.
That is excellent advice.
Best wishes
Rob Cliffe
So:
config = configparser.ConfigParser()
try:
config.read(args.config_file)
except FileNotFoundError as e:
print(f"Error: configuration file {args.config_file} not found: {e}")
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Re: FileNotFoundError thrown due to file name in file, rather than file itself
Chris Angelico writes: > On Tue, 12 Nov 2024 at 01:59, Loris Bennett via Python-list > wrote: >> 2. In terms of generating a helpful error message, how should one >>distinguish between the config file not existing and the log file not >>existing? > > By looking at the exception's attributes rather than assuming and > hard-coding the path in your message? Or, even better, just let the > exception bubble. I didn't consider letting the exception bubble as is the top of the code for a CLI program. I was hoping to just catch what I thought might be a common error of the config file being missing. -- This signature is currently under constuction. -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
Am Tue, Nov 12, 2024 at 09:52:31AM +0100 schrieb Loris Bennett via Python-list:
> Regarding your example above, if 'missingfile.py' contains the following
>
> import configparser
>
> config = configparser.ConfigParser()
>
> try:
> config.read('/foo/bar')
> except FileNotFoundError as e:
> print(f"Error: configuration file {config_file} not found: {e}")
>
> them
>
> python3 missingfile.py
>
> does not produce an any output for me and so does not seem to be a
> reliable way of handling the case where the config file does not exist.
Well:
>>> help(config.read)
Help on method read in module configparser:
read(filenames, encoding=None) method of configparser.ConfigParser
instance
Read and parse a filename or an iterable of filenames.
Files that cannot be opened are silently ignored; this is
designed so that you can specify an iterable of potential
configuration file locations (e.g. current directory, user's
home directory, systemwide directory), and all existing
configuration files in the iterable will be read. A single
filename may also be given.
Return list of successfully read files.
So, the very fact that it does not return any output AND
returns an empty list is the (intended) way of knowing the
error state.
Karsten
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Re: FileNotFoundError thrown due to file name in file, rather than file itself
On Wed, 13 Nov 2024 at 07:29, Mats Wichmann via Python-list wrote: > > On 11/12/24 12:10, Left Right via Python-list wrote: > > > Finally, if you want your logs to go to a file, and currently, your > > only option is stderr, your shell gives you a really, really simple > > way of redirecting stderr to a file. So, really, there aren't any > > excuses to do that. > > an awful lot of the programs that need to do extensive logging don't run > under control of a shell, and thus "shell redirection" helps not at all. > Redirection's still a thing. "Shell redirection" is just the shell syntax to request redirection. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
On 13/11/24 8:10 am, Left Right wrote: since logs are designed to grow indefinitely, the natural response to this design property is log rotation. I don't see how writing logs to stderr solves that problem in any way. Whatever stderr is sent to still has a potentially unlimited amount of data to deal with. But, it's impossible to reliably rotate a log file. There's always a chance that during the rotation some log entries will be written to the file past the point of rotation, but prior to the point where the next logs volume starts. Not sure I follow you there. You seem to be thinking of a particular way of rotating log files, where an external process tries to swap the program's log file out from under it without its knowledge. That could be vulnerable to race conditions. But if the program doing the logging handles the rotation itself, there's no reason it has to lose data. -- Greg -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
On 11/12/24 12:10, Left Right via Python-list wrote: Finally, if you want your logs to go to a file, and currently, your only option is stderr, your shell gives you a really, really simple way of redirecting stderr to a file. So, really, there aren't any excuses to do that. an awful lot of the programs that need to do extensive logging don't run under control of a shell, and thus "shell redirection" helps not at all. -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
Cameron Simpson writes:
> On 11Nov2024 18:24, dieter.mau...@online.de wrote:
>>Loris Bennett wrote at 2024-11-11 15:05 +0100:
>>>I have the following in my program:
>>>try:
>>>logging.config.fileConfig(args.config_file)
>>>config = configparser.ConfigParser()
>>>config.read(args.config_file)
>>>if args.verbose:
>>>print(f"Configuration file: {args.config_file}")
>>>except FileNotFoundError:
>>>print(f"Error: configuration file {args.config_file} not found.
>>> Exiting.")
>>
>>Do not replace full error information (including a traceback)
>>with your own reduced error message.
>>If you omit your "try ... except FileNotFoundError`
>>(or start the `except` clause with a `raise`), you
>>will learn where in the code the exception has been raised
>>and likely as well what was not found (Python is quite good
>>with such error details).
>
> Actually, file-not-found is pretty well defined - the except action
> itself is fine in that regard.
>
> [...]
>>>2. In terms of generating a helpful error message, how should one
>>> distinguish between the config file not existing and the log file not
>>> existing?
>
> Generally you should put a try/except around the smallest possible
> piece of code. So:
>
> config = configparser.ConfigParser()
> try:
> config.read(args.config_file)
> except FileNotFoundError as e:
> print(f"Error: configuration file {args.config_file} not found: {e}")
>
> This way you know that the config file was missing.
I appreciate the point you make about the smallest possible piece of
code, although I can imagine that this could potentially create a lot of
try/except clutter and I might just want a single block and then try to
catch various exceptions.
Regarding your example above, if 'missingfile.py' contains the following
import configparser
config = configparser.ConfigParser()
try:
config.read('/foo/bar')
except FileNotFoundError as e:
print(f"Error: configuration file {config_file} not found: {e}")
them
python3 missingfile.py
does not produce an any output for me and so does not seem to be a
reliable way of handling the case where the config file does not exist.
Cheers,
Loris
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Re: FileNotFoundError thrown due to file name in file, rather than file itself
Chris Angelico writes: > On Tue, 12 Nov 2024 at 01:59, Loris Bennett via Python-list > wrote: >> 2. In terms of generating a helpful error message, how should one >>distinguish between the config file not existing and the log file not >>existing? > > By looking at the exception's attributes rather than assuming and > hard-coding the path in your message? Or, even better, just let the > exception bubble. As Dieter also pointed out, I obviously made a mistake in assuming that I knew what 'FileNotFound' was referring to. However, it strikes me as not immediately obvious that the logging file must exist at this point. I can imagine a situation in which I want to configure a default log file and create it if it missing. Cheers, Loris -- This signature is currently under constuction. -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
Left Right writes:
> Poor error reporting is a very common problem in programming. Python
> is not anything special in this case. Of course, it would've been
> better if the error reported what file wasn't found. But, usually
> these problems are stacking, like in your code. Unfortunately, it's
> your duty, as the language user, to anticipate those problems and act
> accordingly. Now you've learned that the one file you believe that
> could be the source for the error isn't the only one--well, adjust
> your code to differentiate between those two (and potentially other?)
> cases. There's very little else you can do beside that.
>
> NB. On the system level, the error has no information about what file
> wasn't found. It simply returns some numeric value (the famous
> ENOENT) in case when the system call to open a file fails. Python
> could've been more helpful by figuring out what path caused the
> problem and printing that in the error message, but it doesn't...
> That's why I, myself, never use the vanilla FileNotFoundError, I
> always re-rise it with a customized version that incorporates the
> information about the missing file in the error message.
That sounds like a good idea.
> NB2. It's always a bad idea to print logs to files. Any sysadmin /
> ops / infra person worth their salt will tell you that. The only
> place the logs should go to is the standard error. There are true and
> tried tools that can pick up logs from that point on, and do with them
> whatever your heart desires. That is, of course, unless you are
> creating system tools for universal log management (in which case, I'd
> question the choice of Python as a suitable language for such a task).
> Unfortunately, even though this has been common knowledge for decades,
> it's still elusive in the world of application development :|
I am not entirely convinced by NB2. I am, in fact, a sort of sysadmin
person and most of my programs write to a log file. The programs are
also moderately complex, so a single program might access a database,
query an LDAP server, send email etc., so potentially quite a lot can go
wrong. They are also not programs whose output I would pipe to another
command. What would be the advantage of logging to stderr? Quite apart
from that, I find having a log file a useful for debugging when I am
developing.
Cheers,
Loris
> On Mon, Nov 11, 2024 at 4:00 PM Loris Bennett via Python-list
> wrote:
>>
>> Hi,
>>
>> I have the following in my program:
>>
>> try:
>> logging.config.fileConfig(args.config_file)
>> config = configparser.ConfigParser()
>> config.read(args.config_file)
>> if args.verbose:
>> print(f"Configuration file: {args.config_file}")
>> except FileNotFoundError:
>> print(f"Error: configuration file {args.config_file} not found.
>> Exiting.")
>> sys.exit(0)
>>
>> and when I ran the program I got the error
>>
>> Error: configuration file /usr/local/etc/sc_mailer not found. Exiting.
>>
>> However, this file *does* exist and *can* be read. By checking the
>> 'filename' attribute of the exception I discovered that the problem was
>> the log file defined *in* the config file, namely
>>
>> [handler_fileHandler]
>> class=FileHandler
>> level=DEBUG
>> formatter=defaultFormatter
>> args=('/var/log/my_prog.log', 'a')
>>
>> This log file did not exist. The exception is thrown by
>>
>> logging.config.fileConfig(args.config_file)
>>
>> My questions are:
>>
>> 1. Should I be surprised by this behaviour?
>> 2. In terms of generating a helpful error message, how should one
>>distinguish between the config file not existing and the log file not
>>existing?
>>
>> Cheers,
>>
>> Loris
>>
>> --
>> This signature is currently under constuction.
>> --
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Re: FileNotFoundError thrown due to file name in file, rather than file itself
> I am not entirely convinced by NB2. I am, in fact, a sort of sysadmin > person and most of my programs write to a log file. The programs are > also moderately complex, so a single program might access a database, > query an LDAP server, send email etc., so potentially quite a lot can go > wrong. They are also not programs whose output I would pipe to another > command. What would be the advantage of logging to stderr? Quite apart > from that, I find having a log file a useful for debugging when I am > developing. First, the problem with writing to files is that there is no way to make these logs reliable. This is what I mean by saying these are unreliable: since logs are designed to grow indefinitely, the natural response to this design property is log rotation. But, it's impossible to reliably rotate a log file. There's always a chance that during the rotation some log entries will be written to the file past the point of rotation, but prior to the point where the next logs volume starts. There are similar reliability problems with writing to Unix or Internet sockets, databases etc. For different reasons, but at the end of the day, whoever wants logs, they want them to be reliable. Both simplicity and convention selected for stderr as the only and the best source of logging output. Programs that write their output to log files will always irritate their users because users will have to do some detective work to figure out where those files are, and in some cases they will have to do administrative works to make sure that the location where the program wants to store the log files is accessible, has enough free space, is speedy enough etc. So, from the ops perspective, whenever I come across a program that tries to write logs to anything other than stderr, I make an earnest effort to throw that program into the gutter and never touch it again. It's too much headache to babysit every such program, to remember the location of the log files of every such program, the required permissions, to provision storage. If you are in that line of work, you just want all logs to go to the same place (journal), where you can later filter / aggregate / correlate and perform other BI tasks as your heart desires. Of course, if you only administer your own computer, and you have low single digits programs to run, and their behavior doesn't change frequently, and you don't care to drop some records every now and then... it's OK to log to files directly from a program. But then you aren't really in the sysadmin / infra / ops category, as you are more of a hobby enthusiast. Finally, if you want your logs to go to a file, and currently, your only option is stderr, your shell gives you a really, really simple way of redirecting stderr to a file. So, really, there aren't any excuses to do that. -- https://mail.python.org/mailman/listinfo/python-list
Re: FileNotFoundError thrown due to file name in file, rather than file itself
Cameron Simpson wrote at 2024-11-12 08:17 +1100:
>On 11Nov2024 18:24, dieter.mau...@online.de wrote:
>>Loris Bennett wrote at 2024-11-11 15:05 +0100:
>>>I have the following in my program:
>>>try:
>>>logging.config.fileConfig(args.config_file)
>>>config = configparser.ConfigParser()
>>>config.read(args.config_file)
>>>if args.verbose:
>>>print(f"Configuration file: {args.config_file}")
>>>except FileNotFoundError:
>>>print(f"Error: configuration file {args.config_file} not found.
>>> Exiting.")
>>
>>Do not replace full error information (including a traceback)
>>with your own reduced error message.
>>If you omit your "try ... except FileNotFoundError`
>>(or start the `except` clause with a `raise`), you
>>will learn where in the code the exception has been raised
>>and likely as well what was not found (Python is quite good
>>with such error details).
>
>Actually, file-not-found is pretty well defined - the except action
>itself is fine in that regard.
The original exception likely tells us which file was not found.
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