Replace positional argument template by optional

Replace positional argument template by optional argument. This
argument is now needed only in case we process several dates, since
the first date is now read from the NetCDF file.

Inst_eddies/Tests/long_tests.json

@@ -66,7 +66,8 @@
 	    "$build_dir/Inst_eddies/inst_eddies.py", "-b", "1.625", "15.625",
 	    "-38.375", "-30.375",
 	    "$large_input_dir/dt_global_allsat_phy_l4_20060101_20190101.nc",
-	    "dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l", "20060115"
+	    "--template=dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l",
+	    "20060115"
 	]
     },
     {
@@ -76,8 +77,8 @@
 	[
             "$build_dir/Inst_eddies/inst_eddies.py",
 	    "$large_input_dir/dt_global_allsat_phy_l4_20060101_20190101.nc",
-	    "dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l", "2006-01-02",
-	    "-b", "5.875", "12.125", "-32.125", "-26.875"
+	    "--template=dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l",
+	    "2006-01-02", "-b", "5.875", "12.125", "-32.125", "-26.875"
         ]
     }
 ]    

Inst_eddies/Tests/short_tests.json

@@ -303,7 +303,8 @@
 	    "$build_dir/Inst_eddies/inst_eddies.py", "-b", "16.125", "20.875",
 	    "-38.875", "-34.125",
 	    "$large_input_dir/dt_global_allsat_phy_l4_20060101_20190101.nc",
-	    "dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l", "20060102"
+	    "--template=dt_global_allsat_phy_l4_%Y%m%d_20190101.nc", "-l",
+	    "20060102"
 	]
     },
     {
@@ -313,7 +314,7 @@
 	[
             "$build_dir/Inst_eddies/inst_eddies.py",
 	    "$src_dir/Inst_eddies/Tests/Input/Region_1/huv_region_1_2006_01_01.nc",
-	    "huv_region_1_%Y_%m_%d.nc", "-l", "2006-01-04"
+	    "--template=huv_region_1_%Y_%m_%d.nc", "-l", "2006-01-04"
         ]
     },
     {

Inst_eddies/inst_eddies_in.py

@@ -13,13 +13,15 @@ import subprocess
 import shapefile
 import sys
 from dateutil import parser
+import netCDF4
 
 argparser = argparse.ArgumentParser()
 argparser.add_argument("first_file",
                        help = "NetCDF file containing SSH and velocity at a "
                        "single date")
-argparser.add_argument("template",
-                       help = "template of basename with date format")
+argparser.add_argument("--template",
+                       help = "template of basename with date format, only "
+                       "used for several dates")
 argparser.add_argument("-l", "--last_date", help = "%%Y-%%m-%%d")
 argparser.add_argument("-b", "--bbox", nargs=4, type = float,
                        metavar = ("xmin", "xmax", "ymin", "ymax"))
@@ -33,13 +35,23 @@ inst_eddies_exe = "@CMAKE_CURRENT_BINARY_DIR@/inst_eddies"
 if not os.access(inst_eddies_exe, os.X_OK):
     sys.exit(inst_eddies_exe + " not found or not executable")
 
-dirname, basename = path.split(args.first_file)
-my_date = datetime.datetime.strptime(basename, args.template).date()
+# Get the first date from the time coordinate in the NetCDF file:
+with netCDF4.Dataset(args.first_file) as f:
+    my_date = f["time"][:].item()
+
+my_date = round(my_date)
+my_date = datetime.date(1950, 1, 1) + datetime.timedelta(my_date)
+#--
+
+dirname = path.dirname(args.first_file)
 nc_file = args.first_file
 nco_instance = nco.Nco()
 
 if args.last_date:
     last_date = parser.parse(args.last_date).date()
+    
+    if last_date > my_date and not args.template:
+        sys.exit("template option required for several dates")
 else:
     last_date = my_date