use env variables in pre-|post-consume scripts

+ instead of positional arguments because it's easier to use in the
shell script and easier to read in the python code.

docs/advanced_usage.rst

@@ -121,10 +121,10 @@ Pre-consumption script
 ======================
 
 Executed after the consumer sees a new document in the consumption folder, but
-before any processing of the document is performed. This script receives exactly
-one argument:
+before any processing of the document is performed. This script can access the
+following relevant environment variables set:
 
-* Document file name
+* ``DOCUMENT_SOURCE_PATH``
 
 A simple but common example for this would be creating a simple script like
 this:
@@ -134,7 +134,7 @@ this:
 .. code:: bash
 
     #!/usr/bin/env bash
-    pdf2pdfocr.py -i ${1}
+    pdf2pdfocr.py -i ${DOCUMENT_SOURCE_PATH}
 
 ``/etc/paperless.conf``
 
@@ -157,16 +157,16 @@ Post-consumption script
 =======================
 
 Executed after the consumer has successfully processed a document and has moved it
-into paperless. It receives the following arguments:
+into paperless. It receives the following environment variables:
 
-* Document id
-* Generated file name
-* Source path
-* Thumbnail path
-* Download URL
-* Thumbnail URL
-* Correspondent
-* Tags
+* ``DOCUMENT_ID``
+* ``DOCUMENT_FILE_NAME``
+* ``DOCUMENT_SOURCE_PATH``
+* ``DOCUMENT_THUMBNAIL_PATH``
+* ``DOCUMENT_DOWNLOAD_URL``
+* ``DOCUMENT_THUMBNAIL_URL``
+* ``DOCUMENT_CORRESPONDENT``
+* ``DOCUMENT_TAGS``
 
 The script can be in any language, but for a simple shell script
 example, you can take a look at `post-consumption-example.sh`_ in this project.

scripts/post-consumption-example.sh

@@ -1,14 +1,5 @@
 #!/usr/bin/env bash
 
-DOCUMENT_ID=${1}
-DOCUMENT_FILE_NAME=${2}
-DOCUMENT_SOURCE_PATH=${3}
-DOCUMENT_THUMBNAIL_PATH=${4}
-DOCUMENT_DOWNLOAD_URL=${5}
-DOCUMENT_THUMBNAIL_URL=${6}
-DOCUMENT_CORRESPONDENT=${7}
-DOCUMENT_TAGS=${8}
-
 echo "
 
 A document with an id of ${DOCUMENT_ID} was just consumed.  I know the

src/documents/consumer.py

@@ -134,8 +134,11 @@ class Consumer(LoggingMixin):
 
         self.log("info", f"Executing pre-consume script {settings.PRE_CONSUME_SCRIPT}")
 
+        script_env = os.environ.copy()
+        script_env["DOCUMENT_SOURCE_PATH"] = os.path.normpath(self.path)
+
         try:
-            Popen((settings.PRE_CONSUME_SCRIPT, self.path)).wait()
+            Popen(settings.PRE_CONSUME_SCRIPT, env=script_env).wait()
         except Exception as e:
             self._fail(
                 MESSAGE_PRE_CONSUME_SCRIPT_ERROR,
@@ -159,19 +162,29 @@ class Consumer(LoggingMixin):
             f"Executing post-consume script {settings.POST_CONSUME_SCRIPT}",
         )
 
+        script_env = os.environ.copy()
+
+        script_env["DOCUMENT_ID"] = str(document.pk)
+        script_env["DOCUMENT_FILE_NAME"] = document.get_public_filename()
+        script_env["DOCUMENT_SOURCE_PATH"] = os.path.normpath(document.source_path)
+        script_env["DOCUMENT_THUMBNAIL_PATH"] = os.path.normpath(
+            document.thumbnail_path
+        )
+        script_env["DOCUMENT_DOWNLOAD_URL"] = reverse(
+            "document-download", kwargs={"pk": document.pk}
+        )
+        script_env["DOCUMENT_THUMBNAIL_URL"] = reverse(
+            "document-thumb", kwargs={"pk": document.pk}
+        )
+        script_env["DOCUMENT_CORRESPONDENT"] = str(document.correspondent)
+        script_env["DOCUMENT_TAGS"] = str(
+            ",".join(document.tags.all().values_list("name", flat=True))
+        )
+
         try:
             Popen(
-                (
-                    settings.POST_CONSUME_SCRIPT,
-                    str(document.pk),
-                    document.get_public_filename(),
-                    os.path.normpath(document.source_path),
-                    os.path.normpath(document.thumbnail_path),
-                    reverse("document-download", kwargs={"pk": document.pk}),
-                    reverse("document-thumb", kwargs={"pk": document.pk}),
-                    str(document.correspondent),
-                    str(",".join(document.tags.all().values_list("name", flat=True))),
-                ),
+                settings.POST_CONSUME_SCRIPT,
+                env=script_env,
             ).wait()
         except Exception as e:
             self._fail(