Updated utils/printfmt.py

Module given docstrings to explain the purpose and function of defined
module functions. Giving parameter and return values of functions.

Module now contains `gen_log_header` moved from the `Logger` class,
along with global constants for the function.

utils/printfmt.py

@@ -1,7 +1,16 @@
 import textwrap
+import time
 from typing import Union
+
 from .common import LogLevel
 
+
+## log message constant format template
+__LOG_TMPL = "[{DATE}] [{0}] {TYPE}  "
+## string time format (ISO: 8601, long-form)
+__TIMESTAMP_FMT = "%Y-%m-%dT%H:%M:%S%z"
+
+
 class Colours:
     NORMAL = '\033[0m'
     RED    = '\033[91m'
@@ -11,6 +20,12 @@ class Colours:
 
 
 def loglevel_as_str(level: Union[LogLevel, int]) -> str:
+    """Convert an integer or enum value into its appropriate enum
+    attribute name.
+
+    `@Params`: level - `LogLevel | int`
+    `Returns`: LogLevel enum literal attribute name - `str`
+    """
     ## perform a lookup of each attribute of LogLevel and its associate
     ## value, and search for the attribute that has the matching level
     ## value passed to the function. 
@@ -20,10 +35,18 @@ def loglevel_as_str(level: Union[LogLevel, int]) -> str:
         if getattr(LogLevel, _) == level: # if the level matches
             return "{0: <5}".format(_) # return the attribute name
 
-    return "     "
+    return " " * 5
 
 
-def logAsCol(level: Union[int, LogLevel]) -> Colours:
+def log_as_col(level: Union[int, LogLevel]) -> Colours:
+    """Convert an integer or enum value into an associated ANSI escape
+    code terminal colour sequence. Depending on log level severity, an
+    associated colour is returned to give STDOUT text a distinct
+    separation of colour from regular STDOUT text.
+
+    `@Params`: level - `LogLevel | int`
+    `@Return`: Enum of `Colours`
+    """
     ## perform a colour lookup based on level number
     if level == LogLevel.DEBUG:
         return Colours.BLUE
@@ -36,6 +59,54 @@ def logAsCol(level: Union[int, LogLevel]) -> Colours:
     else:
         return Colours.NORMAL
 
+def gen_log_header(_type: Union[LogLevel, int, str]) -> str:
+    """Generate a header string for use of standardising log outputs.
+
+    The header is defined using the following standard header:
+    ```plaintext
+        "[YYYY-MM-DDTHH:MM:SS+OFFSET] [{CALLER}] <LogLevel>  {0}"
+    ```
+    
+    The first column defines the Date-Time following the ISO 8601 (long)
+    standard timestamp format, whereby `T` is the separator between Date
+    and Time. The `+OFFSET` is the number of hours ahead/behind UTC, the
+    currently timezone set by the PC. This is achieved using the following
+    string to time format:
+    `%Y-%m-%dT%H:%M:%S%z`.
+
+    The second column is reversed during the return value of the string.
+    This column is used to allow for a stacktrace to be attached to the
+    log message.
+
+    The third column defines the level of the log message. This will be
+    five blank space characters if a level is passed outside of the
+    defined scope of logging levels.
+
+    The fourth column is reserved during the return value of the string.
+    It represents the body of the message to be logged.
+
+
+    `@Params`: _type - `LogLevel | int | str`
+    `@Return`: Formattable string - `str`
+    """
+    ## if the _type represents a LogLevel value, convert it to str
+    if not isinstance(_type, str):
+        _type = loglevel_as_str(_type)
+
+    ## return newly formatted log message header 
+    return __LOG_TMPL.format('{CALLER}', DATE=\
+        time.strftime(__TIMESTAMP_FMT, time.localtime()),
+        TYPE=_type) + "{0}"
+
 
 def wrap(value: str, *, width: int = 120, tb_size: int = 4) -> str:
+    """Return a hard-wrapped string defined by a fixed width.
+
+    Wrapped text is separated by a `\\n` character and a fixed width of
+    120 characters. Each wrap is appended with a tab size of 4 characters
+    at the start of each line-wrap.
+
+    `@Params`: value - `str`, width = 120 - `int`, tb_size = 4 - `int`
+    `@Return`: `str`
+    """
     return "\n".join(textwrap.wrap(value, width=width, tabsize=tb_size))