super verbose python tracebacks

traceback.py

import sys
import traceback
import linecache

def printlocals(frame, truncate=500, truncate__=True):
    sep = '.' * 50
    msg = '    %s\n' % sep
    for name, value in sorted(frame.f_locals.items()):
        if hasattr(value, '__repr__'):
            try:
                val_str = value.__repr__()
            except:
                val_str = "<error when calling __repr__>"
        else:
            try:
                val_str = str(value)
            except:
                val_str = "<error calling str()>"

        if truncate and len(val_str) > truncate:
            val_str = "%s..." % val_str[:truncate]
        if truncate__ and name.startswith('__') and len(val_str) > 50:
            val_str = "%s..." % val_str[:50]

        val_str = val_str.replace('\n', '\n        %s' % (' ' * (len(name) + 2)))
        msg += "       %s = %s\n" % (name, val_str)
    msg += '    %s' % sep
    return msg

def tb2string(tb, context=5):
    frame_strings = []
    while tb:
        frame = tb.tb_frame
        filename, name = (frame.f_code.co_filename, frame.f_code.co_name)
        lineno = tb.tb_lineno - 1
        msg = "%s in %s\n" % (filename, frame.f_code.co_name)

        lines = linecache.getlines(filename)
        start = max(lineno - context, 0)
        stop = lineno + 1
        for line_idx in range(start, stop+1):
            if line_idx == lineno:
                line_str = "--> %s " % line_idx
            else:
                line_str = "    %s " % line_idx
            try:
                line_str += lines[line_idx]
            except IndexError:
                line_str += '<error reading line>'
            msg += line_str

        msg += printlocals(frame)
        frame_strings.append(msg)
        tb = tb.tb_next

    return '\n\n\n'.join(frame_strings)

def format_traceback(tb, etype=None, evalue=None):
    msg = tb2string(tb)
    if etype is not None and evalue is not None:
        exc_str = ' '.join(traceback.format_exception_only(etype, evalue))
        msg += '\n\n' + exc_str
    return msg



if __name__ == '__main__':
    import numpy as np
    np.set_printoptions(linewidth=70)
    rng = np.random.RandomState()

    def a_broken_function(foo):
        list_of_things = [foo, foo]
        somestring = "yet another string"
        somearray = rng.randint(0,9,size=(100,100))
        for k in range(10):
            if k == 9:
                raise Exception('hello!')

    def some_function(boing):
        foo = boing + "world"
        a_broken_function(foo)

    try:
        some_function("hello")
    except:
        etype, exc, tb = sys.exc_info()
        print(format_traceback(tb, etype, exc))
        
        
        
    

verbose_python_tracebacks.md

Extra verbose python traceback formatting with current variable values (because sometimes there's no debugger, only a log file)

Before:

Traceback (most recent call last):
  File "tracebacks.py", line 85, in <module>
    some_function("hello")
  File "tracebacks.py", line 82, in some_function
    a_broken_function(foo)
  File "tracebacks.py", line 78, in a_broken_function
    raise Exception('hello!')
Exception: hello!

After:

(...)

/home/.../projects/tracebacks/tracebacks.py in some_function
    76             if k == 9:
    77                 raise Exception('hello!')
    78 
    79     def some_function(boing):
    80         foo = boing + "world"
--> 81         a_broken_function(foo)
    82 
    ..................................................
       boing = 'hello'
       foo = 'helloworld'
    ..................................................


/home/.../projects/tracebacks/tracebacks.py in a_broken_function
    72         list_of_things = [foo, foo]
    73         somestring = "yet another string"
    74         somearray = rng.randint(0,9,size=(100,100))
    75         for k in range(10):
    76             if k == 9:
--> 77                 raise Exception('hello!')
    78 
    ..................................................
       foo = 'helloworld'
       k = 9
       list_of_things = ['helloworld', 'helloworld']
       somearray = array([[6, 4, 1, ..., 0, 4, 6],
                          [5, 7, 0, ..., 4, 3, 2],
                          [8, 6, 8, ..., 3, 8, 1],
                          ...,
                          [4, 1, 0, ..., 0, 4, 7],
                          [6, 5, 1, ..., 5, 6, 4],
                          [0, 4, 5, ..., 6, 6, 1]])
       somestring = 'yet another string'
    ..................................................

Exception: hello!