Add configurable requests cache directory

As I expected, on Google App Engine we can't write the cache file
to the current working directory. I modified csv-metadata-quality
CLI to check for the REQUESTS_CACHE_DIR environment variable so we
don't really have to do anything different other than setting the
variable.

main.py

@@ -68,12 +68,22 @@ def process():
         if "experimental" in request.form:
             args.append("-e")
 
+        # Set cache dir to our upload path so we can tell csv-metadata-quality
+        # to store its requests-cache database there instead of in the current
+        # working directory (we can only write to /tmp on Google App Engine).
+        # Also, make sure to keep our PATH!
+        env = {
+            "REQUESTS_CACHE_DIR": app.config["UPLOAD_PATH"],
+            "PATH": os.environ["PATH"],
+        }
+
         # run subprocess and capture output as UTF-8 so we get a string instead of
         # bytes for ansi2html
         results = subprocess.run(
             ["csv-metadata-quality"] + args,
             capture_output=True,
             encoding="UTF-8",
+            env=env,
         )
         # convert the output to HTML using ansi2html
         conv = Ansi2HTMLConverter()

poetry.lock

@@ -107,8 +107,8 @@ xlrd = "^1.2.0"
 [package.source]
 type = "git"
 url = "https://github.com/ilri/csv-metadata-quality.git"
-reference = "1008acf35e2753d9194755dd186c5428a0c520e6"
-resolved_reference = "1008acf35e2753d9194755dd186c5428a0c520e6"
+reference = "0e9176f0a6f694e85d38bf15c6b80708402bfa8b"
+resolved_reference = "0e9176f0a6f694e85d38bf15c6b80708402bfa8b"
 
 [[package]]
 name = "decorator"

pyproject.toml

@@ -7,7 +7,7 @@ license = "AGPL-3.0-only"
 
 [tool.poetry.dependencies]
 python = "^3.7.1"
-csv-metadata-quality = {git = "https://github.com/ilri/csv-metadata-quality.git", rev = "1008acf35e2753d9194755dd186c5428a0c520e6"}
+csv-metadata-quality = {git = "https://github.com/ilri/csv-metadata-quality.git", rev = "0e9176f0a6f694e85d38bf15c6b80708402bfa8b"}
 Flask = "^1.1.2"
 ansi2html = "^1.6.0"
 gunicorn = "^20.0.4"