From 7aa199afc08420380683a64901957dd9f0d1d3cd Mon Sep 17 00:00:00 2001
From: Rob Berwick <rob.berwick@gmail.com>
Date: Sat, 27 Jul 2024 20:05:41 +0100
Subject: [PATCH] Add docker based grype backend

---
 pygrype/__init__.py             |  1 +
 pygrype/core/backends/docker.py | 50 +++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 pygrype/core/backends/docker.py

diff --git a/pygrype/__init__.py b/pygrype/__init__.py
index ae61536..b69333a 100644
--- a/pygrype/__init__.py
+++ b/pygrype/__init__.py
@@ -1,3 +1,4 @@
 from .grype import Grype
 from .core.backends.binary import GrypeBinaryBackend
+from .core.backends.docker import GrypeDockerBackend
 
diff --git a/pygrype/core/backends/docker.py b/pygrype/core/backends/docker.py
new file mode 100644
index 0000000..d1e977f
--- /dev/null
+++ b/pygrype/core/backends/docker.py
@@ -0,0 +1,50 @@
+import subprocess
+from subprocess import CompletedProcess
+
+from pygrype.core.backends.base import GrypeBackend
+
+
+DOCKER_EXE = 'docker'
+IMAGE_NAME = 'anchore/grype'
+
+
+class GrypeDockerBackend(GrypeBackend):
+
+    def __init__(self, tag: str = "latest") -> None:
+        self.tag: str = tag
+        super().__init__()
+
+    @property
+    def docker_image(self) -> str:
+        return f"{IMAGE_NAME}:{self.tag}"
+
+    def ensure_backend(self):
+        try:
+            # Check if Docker is installed
+            subprocess.run(
+                [DOCKER_EXE, '--version'],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE
+            )
+        except subprocess.CalledProcessError:
+            raise Exception("Docker is not installed or not available in the PATH.")
+
+        try:
+            # Ensure the required Docker image is available
+            subprocess.run(
+                [DOCKER_EXE, 'pull', self.docker_image],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE
+            )
+        except subprocess.CalledProcessError:
+            raise Exception(f"Failed to pull the required Docker image '{self.docker_image}'.")
+
+    @property
+    def executable_string(self) -> str:
+        return DOCKER_EXE
+
+    def execute(self, *args) -> CompletedProcess:
+        docker_args = ['run', '--rm', self.docker_image] + list(args)
+        return super().execute(*docker_args)