brn: Introduce BRN as a class

.pylintrc

@@ -0,0 +1,5 @@
+[MASTER]
+ignored-classes=Column
+load-plugins=pylint_flask,pylint_flask_sqlalchemy
+py-version=3.8
+suggestion-mode=yes

app/brm/__init__.py

@@ -0,0 +1,3 @@
+"""
+Bypass Censorship Resource Management API.
+"""

app/brm/brn.py

@@ -0,0 +1,58 @@
+"""
+Bypass Censorship Resource Names.
+"""
+
+from __future__ import annotations
+from dataclasses import dataclass, field
+from typing import Any
+
+from flask import current_app
+
+from app.brm.utils import is_integer
+
+
+def global_namespace() -> str:
+    return str(current_app.config["GLOBAL_NAMESPACE"])
+
+
+@dataclass
+class BRN:
+    group_id: int
+    product: str
+    provider: str
+    resource_type: str
+    resource_id: str
+    global_namespace: str = field(default_factory=global_namespace)
+
+    @classmethod
+    def from_str(cls, s: str) -> BRN:
+        parts = s.split(":")
+        if len(parts) != 6 or parts[0].lower() != "brn" or not is_integer(parts[2]):
+            raise TypeError(f"Expected a valid BRN but got {repr(s)}.")
+        resource_parts = parts[4].split("/")
+        if len(resource_parts) != 5:
+            raise TypeError(f"Expected a valid BRN but got {repr(s)}.")
+        return cls(
+            global_namespace=parts[1],
+            group_id=int(parts[2]),
+            product=parts[3],
+            provider=parts[4],
+            resource_type=resource_parts[0],
+            resource_id=resource_parts[1]
+        )
+
+    def __eq__(self, other: Any) -> bool:
+        return str(self) == str(other)
+
+    def __str__(self) -> str:
+        return ":".join([
+            "brn",
+            self.global_namespace,
+            str(self.group_id),
+            self.product,
+            self.provider,
+            f"{self.resource_type}/{self.resource_id}"
+        ])
+
+    def __repr__(self) -> str:
+        return f"<BRN {str(self)}>"

app/brm/utils.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from typing import Any
+
+
+def is_integer(n: Any) -> bool:
+    """
+    Determine if a string (or other object type that can be converted automatically) represents an integer.
+
+    Thanks to https://note.nkmk.me/en/python-check-int-float/.
+
+    :param n: object to test
+    :return: true if it's an integer
+    """
+    try:
+        float(n)
+    except ValueError:
+        return False
+    else:
+        return float(n).is_integer()

app/models/__init__.py

@@ -3,6 +3,7 @@ from datetime import datetime
 from typing import Union, List, Optional, Any
 
 from app.alarms import alarms_for
+from app.brm.brn import BRN
 from app.extensions import db
 from app.models.alarms import Alarm
 
@@ -73,7 +74,7 @@ class AbstractResource(db.Model):  # type: ignore
 
     @property
     @abstractmethod
-    def brn(self) -> str:
+    def brn(self) -> BRN:
         raise NotImplementedError()
 
     def deprecate(self, *, reason: str) -> None:

app/models/mirrors.py

@@ -3,6 +3,7 @@ from typing import Optional, List
 from flask import current_app
 from tldextract import extract
 
+from app.brm.brn import BRN
 from app.extensions import db
 from app.models import AbstractConfiguration, AbstractResource
 from app.models.onions import Onion
@@ -53,8 +54,14 @@ class Proxy(AbstractResource):
     origin = db.relationship("Origin", back_populates="proxies")
 
     @property
-    def brn(self) -> str:
-        return f"brn:{current_app.config['GLOBAL_NAMESPACE']}:{self.origin.group_id}:mirror:{self.provider}:proxy/{self.id}"
+    def brn(self) -> BRN:
+        return BRN(
+            group_id=self.origin.group_id,
+            product="mirror",
+            provider=self.provider,
+            resource_type="proxy",
+            resource_id=self.id
+        )
 
     @classmethod
     def csv_header(cls) -> List[str]:
@@ -72,5 +79,11 @@ class SmartProxy(AbstractResource):
     group = db.relationship("Group", back_populates="smart_proxies")
 
     @property
-    def brn(self) -> str:
-        return f"brn:{current_app.config['GLOBAL_NAMESPACE']}:{self.group_id}:mirror:{self.provider}:smart-proxy/1"
+    def brn(self) -> BRN:
+        return BRN(
+            group_id=self.group_id,
+            product="mirror",
+            provider=self.provider,
+            resource_type="smart_proxy",
+            resource_id=str(1)
+        )

app/models/onions.py

@@ -1,5 +1,4 @@
-from flask import current_app
-
+from app.brm.brn import BRN
 from app.extensions import db
 from app.models import AbstractConfiguration, AbstractResource
 
@@ -21,5 +20,11 @@ class Eotk(AbstractResource):
     group = db.relationship("Group", back_populates="eotks")
 
     @property
-    def brn(self) -> str:
-        return f"brn:{current_app.config['GLOBAL_NAMESPACE']}:{self.group_id}:eotk:{self.provider}:instance/{self.region}"
+    def brn(self) -> BRN:
+        return BRN(
+            group_id=self.group_id,
+            provider=self.provider,
+            product="eotk",
+            resource_type="instance",
+            resource_id=self.region
+        )

requirements.txt

@@ -10,6 +10,8 @@ flask-wtf
 flask~=2.0.2
 jinja2~=3.0.2
 pydantic
+pylint-flask-sqlalchemy
+pylint-flask
 pyyaml~=6.0
 requests~=2.27.1
 sqlalchemy~=1.4.32