Fix handling of prefixed Asset IDs and sorting of the asset list (#382)

* FIX: Remove misleading admin site title

* Moved across assets_id sorting to use proper numeric values. Also mofifies SQL command to find free asset IDs so that it works on postgres.

* Changed generateSampleAssetsData.py to include prefices on some cables.

* Fixed pep8

* Fixed missed migration

* Ensured hidden asset fields are completed on every database write

* CMULTI is a thing, and therefore a max prefix length of 5 cannot be a thing

assets/admin.py

@@ -30,8 +30,3 @@ class AssetAdmin(admin.ModelAdmin):
 @admin.register(assets.Connector)
 class ConnectorAdmin(admin.ModelAdmin):
     list_display = ['id', '__str__', 'current_rating', 'voltage_rating', 'num_pins']
-
-
-admin.AdminSite.site_header = 'PyAssets - TEC\'s Asset System'
-admin.AdminSite.site_title = 'PyAssets Admin'
-admin.AdminSite.index_title = 'System Administration'

assets/forms.py

@@ -7,6 +7,7 @@ class AssetForm(forms.ModelForm):
     class Meta:
         model = models.Asset
         fields = '__all__'
+        exclude = ['asset_id_prefix', 'asset_id_number']
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)

assets/management/commands/generateSampleAssetsData.py

@@ -1,8 +1,7 @@
+import random
 from django.core.management.base import BaseCommand, CommandError
 from django.utils import timezone
-
 from assets import models
-import random
 
 
 class Command(BaseCommand):
@@ -50,7 +49,7 @@ class Command(BaseCommand):
         suppliers = models.Supplier.objects.all()
 
         for i in range(100):
-            asset = models.Asset.objects.create(
+            asset = models.Asset(
                 asset_id='{}'.format(models.Asset.get_available_asset_id()),
                 description=random.choice(asset_description),
                 category=random.choice(categories),
@@ -63,11 +62,12 @@ class Command(BaseCommand):
 
             if i % 3 == 0:
                 asset.purchased_from = random.choice(suppliers)
-
+            asset.clean()
             asset.save()
 
     def create_cables(self):
         asset_description = ['The worm', 'Harting without a cap', 'Heavy cable', 'Extension lead', 'IEC cable that we should remember to prep']
+        asset_prefixes = ["C", "C4P", "CBNC", "CDMX", "CDV", "CRCD", "CSOCA", "CXLR"]
 
         csas = [0.75, 1.00, 1.25, 2.5, 4]
         lengths = [1, 2, 5, 10, 15, 20, 25, 30, 50, 100]
@@ -79,7 +79,7 @@ class Command(BaseCommand):
         connectors = models.Connector.objects.all()
 
         for i in range(100):
-            asset = models.Asset.objects.create(
+            asset = models.Asset(
                 asset_id='{}'.format(models.Asset.get_available_asset_id()),
                 description=random.choice(asset_description),
                 category=random.choice(categories),
@@ -95,12 +95,17 @@ class Command(BaseCommand):
                 cores=random.choice(circuits)
             )
 
+            if i % 5 == 0:
+                prefix = random.choice(asset_prefixes)
+                asset.asset_id = prefix + str(models.Asset.get_available_asset_id(wanted_prefix=prefix))
+
             if i % 4 == 0:
                 asset.parent = models.Asset.objects.order_by('?').first()
 
             if i % 3 == 0:
                 asset.purchased_from = random.choice(suppliers)
 
+            asset.clean()
             asset.save()
 
     def create_connectors(self):

assets/migrations/0008_auto_20191205_1937_squashed_0009_auto_20191205_2041.py

@@ -0,0 +1,64 @@
+# Generated by Django 2.0.13 on 2019-12-05 20:42
+
+from django.db import migrations, models
+import django.db.migrations.operations.special
+
+def forwards(apps, schema_editor):
+    AssetModel = apps.get_model('assets', 'Asset')
+    
+    for row in AssetModel.objects.all():
+
+        row.asset_id = row.asset_id.upper()
+        asset_search = re.search("^([A-Z0-9]*?[A-Z]?)([0-9]+)$", row.asset_id)
+        if asset_search is None: # If the asset_id doesn't have a number at the end
+            row.asset_id += "1"
+        
+        asset_search = re.search("^([A-Z0-9]*?[A-Z]?)([0-9]+)$", row.asset_id)
+        row.asset_id_prefix = asset_search.group(1)
+        row.asset_id_number = int(asset_search.group(2))
+
+        row.save(update_fields=['asset_id', 'asset_id_prefix', 'asset_id_number'])
+
+# Functions from the following migrations need manual copying.
+# Move them and any dependencies into this file, then update the
+# RunPython operations to refer to the local versions:
+# assets.migrations.0008_auto_20191205_1937
+
+class Migration(migrations.Migration):
+
+    replaces = [('assets', '0008_auto_20191205_1937'), ('assets', '0009_auto_20191205_2041')]
+
+    dependencies = [
+        ('assets', '0007_auto_20190108_0202_squashed_0014_auto_20191017_2052'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='asset',
+            name='asset_id_number',
+            field=models.IntegerField(default=1),
+        ),
+        migrations.AddField(
+            model_name='asset',
+            name='asset_id_prefix',
+            field=models.CharField(default='', max_length=5),
+        ),
+        migrations.RunPython(
+            code=forwards,
+            reverse_code=django.db.migrations.operations.special.RunPython.noop,
+        ),
+        migrations.AlterModelOptions(
+            name='asset',
+            options={'ordering': ['asset_id_prefix', 'asset_id_number'], 'permissions': (('asset_finance', 'Can see financial data for assets'), ('view_asset', 'Can view an asset'))},
+        ),
+        migrations.AlterField(
+            model_name='asset',
+            name='asset_id',
+            field=models.CharField(max_length=15, unique=True),
+        ),
+        migrations.AlterField(
+            model_name='asset',
+            name='asset_id_prefix',
+            field=models.CharField(default='', max_length=8),
+        ),
+    ]

assets/models.py

@@ -3,6 +3,9 @@ from django.core.exceptions import ValidationError
 from django.db import models, connection
 from django.urls import reverse
 
+from django.db.models.signals import pre_save
+from django.dispatch.dispatcher import receiver
+
 
 class AssetCategory(models.Model):
     class Meta:
@@ -54,14 +57,14 @@ class Connector(models.Model):
 
 class Asset(models.Model):
     class Meta:
-        ordering = ['asset_id']
+        ordering = ['asset_id_prefix', 'asset_id_number']
         permissions = (
             ('asset_finance', 'Can see financial data for assets'),
             ('view_asset', 'Can view an asset')
         )
 
     parent = models.ForeignKey(to='self', related_name='asset_parent', blank=True, null=True, on_delete=models.SET_NULL)
-    asset_id = models.CharField(max_length=10, unique=True)
+    asset_id = models.CharField(max_length=15, unique=True)
     description = models.CharField(max_length=120)
     category = models.ForeignKey(to=AssetCategory, on_delete=models.CASCADE)
     status = models.ForeignKey(to=AssetStatus, on_delete=models.CASCADE)
@@ -83,18 +86,24 @@ class Asset(models.Model):
     circuits = models.IntegerField(blank=True, null=True)
     cores = models.IntegerField(blank=True, null=True)
 
-    def get_available_asset_id():
+    # Hidden asset_id components
+    # For example, if asset_id was "C1001" then asset_id_prefix would be "C" and number "1001"
+    asset_id_prefix = models.CharField(max_length=8, default="")
+    asset_id_number = models.IntegerField(default=1)
+
+    def get_available_asset_id(wanted_prefix=""):
         sql = """
-        SELECT MIN(CAST(a.asset_id AS int))+1
+        SELECT a.asset_id_number+1
         FROM assets_asset a
         LEFT OUTER JOIN assets_asset b ON
-            (CAST(a.asset_id AS int) + 1 = CAST(b.asset_id AS int))
+            (a.asset_id_number + 1 = b.asset_id_number AND
-        WHERE b.asset_id IS NULL AND CAST(a.asset_id AS int) >= %s;
+            a.asset_id_prefix = b.asset_id_prefix)
+        WHERE b.asset_id IS NULL AND a.asset_id_number >= %s AND a.asset_id_prefix = %s;
         """
         with connection.cursor() as cursor:
-            cursor.execute(sql, [9000])
+            cursor.execute(sql, [9000, wanted_prefix])
             row = cursor.fetchone()
-            if row[0] is None:
+            if row is None or row[0] is None:
                 return 9000
             else:
                 return row[0]
@@ -114,8 +123,9 @@ class Asset(models.Model):
             errdict["date_sold"] = ["Cannot sell an item before it is acquired"]
 
         self.asset_id = self.asset_id.upper()
-        if re.search("^[a-zA-Z0-9]+$", self.asset_id) is None:
+        asset_search = re.search("^([a-zA-Z0-9]*?[a-zA-Z]?)([0-9]+)$", self.asset_id)
-                errdict["asset_id"] = ["An Asset ID can only consist of letters and numbers"]
+        if asset_search is None:
+                errdict["asset_id"] = ["An Asset ID can only consist of letters and numbers, with a final number"]
 
         if self.purchase_price and self.purchase_price < 0:
             errdict["purchase_price"] = ["A price cannot be negative"]
@@ -139,3 +149,14 @@ class Asset(models.Model):
 
         if errdict != {}:  # If there was an error when validation
             raise ValidationError(errdict)
+
+
+@receiver(pre_save, sender=Asset)
+def pre_save_asset(sender, instance, **kwargs):
+    """Automatically fills in hidden members on database access"""
+    asset_search = re.search("^([a-zA-Z0-9]*?[a-zA-Z]?)([0-9]+)$", instance.asset_id)
+    if asset_search is None:
+        instance.asset_id += "1"
+    asset_search = re.search("^([a-zA-Z0-9]*?[a-zA-Z]?)([0-9]+)$", instance.asset_id)
+    instance.asset_id_prefix = asset_search.group(1)
+    instance.asset_id_number = int(asset_search.group(2))