Improve command output with text banner, colour and alignment

cats/__init__.py

@@ -14,6 +14,7 @@
 from .configure import get_runtime_config
 from .forecast import CarbonIntensityAverageEstimate
 from .optimise_starttime import get_avg_estimates  # noqa: F401
+from .constants import CATS_ASCII_BANNER_COLOUR, CATS_ASCII_BANNER_NO_COLOUR
 
 __version__ = "1.0.0"
 
@@ -182,6 +183,12 @@ def positive_integer(string):
         type=positive_integer,
         help="Amount of memory used by the job, in GB",
     )
+    parser.add_argument(
+        "-n",
+        "--no-colour",  # or could use American spelling like many other CLIs?
+        action="store_true",
+        help="Disable all terminal output colouring",
+    )
 
     return parser
 
@@ -194,19 +201,41 @@ class CATSOutput:
     carbonIntensityOptimal: CarbonIntensityAverageEstimate
     location: str
     countryISO3: str
+    colour: bool
     emmissionEstimate: Optional[Estimates] = None
 
     def __str__(self) -> str:
-        out = f"""Best job start time {self.carbonIntensityOptimal.start}
-Carbon intensity if job started now       = {self.carbonIntensityNow.value:.2f} gCO2eq/kWh
-Carbon intensity at optimal time          = {self.carbonIntensityOptimal.value:.2f} gCO2eq/kWh"""
+        if self.colour:
+            # Default colour
+            col_normal = "\33[0m"  # reset any colour
+
+            # Optimal information colours
+            col_dt_opt = "\33[32m"  # green i.e. 'good' in traffic light rating
+            col_ci_opt = "\33[32m"  # green
+            col_ee_opt = "\33[32m"  # green
+
+            # 'NOw' non-optimal colours
+            col_ci_now = "\33[31m"  # red i.e. 'bad' in traffic light rating
+            col_ee_now = "\33[31m"  # red
+        else:
+            col_normal = ""
+            col_dt_opt = ""
+            col_ci_opt = ""
+            col_ci_now = ""
+            col_ee_now = ""
+            col_ee_opt = ""
+
+        out = f"""
+Best job start time                       = {col_dt_opt}{self.carbonIntensityOptimal.start}{col_normal}
+Carbon intensity if job started now       = {col_ci_now}{self.carbonIntensityNow.value:.2f} gCO2eq/kWh{col_normal}
+Carbon intensity at optimal time          = {col_ci_opt}{self.carbonIntensityOptimal.value:.2f} gCO2eq/kWh{col_normal}"""
 
         if self.emmissionEstimate:
             out += f"""
-Estimated emissions if job started now    = {self.emmissionEstimate.now}
-Estimated emissions at optimal time       = {self.emmissionEstimate.best} (- {self.emmissionEstimate.savings})"""
+Estimated emissions if job started now    = {col_ee_now}{self.emmissionEstimate.now}{col_normal}
+Estimated emissions at optimal time       = {col_ee_opt}{self.emmissionEstimate.best} (- {self.emmissionEstimate.savings}){col_normal}"""
 
-        out += "\n\nUse --format=json to get this in machine readable format"
+        logging.info("Use '--format=json' to get this in machine readable format")
         return out
 
     def to_json(self, dateformat: str = "", **kwargs) -> str:
@@ -222,6 +251,15 @@ def to_json(self, dateformat: str = "", **kwargs) -> str:
         return json.dumps(data, **kwargs)
 
 
+def print_banner(colour):
+    """Print an ASCII art banner with the CATS title, optionally in colour.
+    """
+    if colour:
+        print(CATS_ASCII_BANNER_COLOUR)
+    else:
+        print(CATS_ASCII_BANNER_NO_COLOUR)
+
+
 def schedule_at(
     output: CATSOutput, args: list[str], at_command: str = "at"
 ) -> Optional[str]:
@@ -251,6 +289,10 @@ def schedule_at(
 def main(arguments=None) -> int:
     parser = parse_arguments()
     args = parser.parse_args(arguments)
+
+    # Print CATS ASCII art banner, before any output from printing or logging
+    print_banner(not args.no_colour)
+
     if args.command and not args.scheduler:
         print(
             "cats: To run a command with the -c or --command option, you must\n"
@@ -287,7 +329,7 @@ def main(arguments=None) -> int:
     # Find best possible average carbon intensity, along
     # with corresponding job start time.
     now_avg, best_avg = get_avg_estimates(CI_forecast, duration=duration)
-    output = CATSOutput(now_avg, best_avg, location, "GBR")
+    output = CATSOutput(now_avg, best_avg, location, "GBR", not args.no_colour)
 
     ################################
     ## Calculate carbon footprint ##

cats/constants.py

@@ -1 +1,20 @@
 MEMORY_POWER_PER_GB = 0.3725  # W/GB
+
+CATS_ASCII_BANNER_COLOUR = """
+\33[34mThe\33[35m.\33[34m\33[37m____ \33[35m..... \33[37m__ \33[35m.... \33[37m________ \33[35m. \33[37m______\33[35m...
+\33[35m.. \33[37m/  __)\33[35m.....\33[37m/  \\\33[35m....\33[37m(__    __)\33[35m.\33[37m)  ____)\33[35m....
+\33[35m..\33[37m|  /\33[35m.......\33[37m/    \\\33[35m......\33[37m|  |\33[35m...\33[37m(  (___\33[35m........
+\33[35m..\33[37m| |\33[34mlimate\33[35m.\33[37m/  ()  \\\33[34mware\33[35m.\33[37m|  |\33[34mask\33[35m.\33[37m\\___  \\\33[34mcheduler
+\33[35m..\33[37m|  \\__\33[35m...\33[37m|   __   |\33[35m....\33[37m|  |\33[35m....\33[37m____)  )\33[35m....
+\33[35m...\33[37m\\    )\33[35m..\33[37m|  (\33[35m..\33[37m)  |\33[35m....\33[37m|  |\33[35m...\33[37m(      (\33[35m..\33[0m
+"""
+
+# Same as above but without the colour codes, so not given custom colouring
+CATS_ASCII_BANNER_NO_COLOUR = """
+The.____ ..... __ .... ________ . ______ ...
+.. /  __)...../  \\....(__    __).)  ____)....
+..|  /......./    \\......|  |...(  (___........
+..| |limate./  ()  \\ware.|  |ask.\\___  \\cheduler
+..|  \\__...|   __   |....|  |....____)  )....
+...\\    )..|  (..)  |....|  |...(      (..
+"""