#165: Allow tmp directory to be configured for nox sessions

README.md

@@ -30,7 +30,8 @@ machine.
 To start, install [pyenv](https://github.com/pyenv/pyenv). There is a Windows version of
 this tool ([pyenv-win](https://github.com/pyenv-win/pyenv-win)), however this is
 currently untested on this repo. This is used to manage the various versions of Python
-that will be used to test/lint Python during development. Install by executing the following:
+that will be used to test/lint Python during development. Install by executing the
+following:
 
 ```bash
 curl https://pyenv.run | bash
@@ -154,6 +155,21 @@ Currently, the following Nox sessions have been created:
   dependencies (pulled directly from Poetry) for any known vulnerabilities. This session
   gives the output in a full ASCII style report.
 
+Each Nox session builds an environment using the repo's dependencies (defined using
+Poetry) using `install_with_constraints()`. This stores the dependencies in a
+`requirements.txt`-like format temporarily during this process, using the OS' default
+temporary location. This could result in permissions issues (this has been seen by a
+colleague on Windows), so adding the `--tmpdir [DIRECTORY PATH]` allows the user to
+define where this file should be stored. Due to Nox session being initiated in the
+command line, this argument needs to be a positional argument (denoted by the `--` in
+the Nox command). This argument is optional, but **must** be the final argument avoid
+interference with Nox's argument parsing. An example:
+
+```bash
+nox -s lint -- util datagateway_api --tmpdir /root
+```
+
+
 ### Pre Commit (Automated Checks during Git Commit)
 To make use of Git's ability to run custom hooks, [pre-commit](https://pre-commit.com/)
 is used. Like Nox, Pip is used to install this tool:

datagateway_api/src/swagger/initialise_spec.py

@@ -145,7 +145,7 @@ def initialise_spec(spec):
                 "lt": {"value": [{"id": {"lt": 10}}]},
                 "lte": {"value": [{"id": {"lte": 50}}]},
                 "gt": {"value": [{"id": {"gt": 10}}]},
-                "gte": {"value": [{"id": {"gte": 50}}]},  
+                "gte": {"value": [{"id": {"gte": 50}}]},
                 "in": {"value": [{"id": {"in": [1, 2, 3]}}]},
             },
         },

noxfile.py

@@ -1,13 +1,15 @@
-import nox
 import tempfile
 
+import nox
+
+
 # Separating Black away from the rest of the sessions
 nox.options.sessions = "lint", "safety"
 code_locations = "datagateway_api", "test", "util", "noxfile.py"
 
 
-def install_with_constraints(session, *args, **kwargs):
-    with tempfile.NamedTemporaryFile() as requirements:
+def install_with_constraints(session, req_dir=None, *args, **kwargs):
+    with tempfile.NamedTemporaryFile(dir=req_dir) as requirements:
         session.run(
             "poetry",
             "export",
@@ -19,18 +21,35 @@ def install_with_constraints(session, *args, **kwargs):
         session.install(f"--constraint={requirements.name}", *args, **kwargs)
 
 
+def get_tmp_dir(session):
+    tmp_dir = None
+
+    try:
+        if session.posargs[-2] == "--tmpdir":
+            tmp_dir = session.posargs.pop(-1)
+            session.posargs.remove("--tmpdir")
+    except IndexError:
+        session.log("Info: No --tmpdir option given")
+
+    return tmp_dir
+
+
 @nox.session(python="3.6", reuse_venv=True)
 def format(session):
+    tmp_dir = get_tmp_dir(session)
     args = session.posargs or code_locations
-    install_with_constraints(session, "black")
+
+    install_with_constraints(session, tmp_dir, "black")
     session.run("black", *args, external=True)
 
 
 @nox.session(python="3.6", reuse_venv=True)
 def lint(session):
+    tmp_dir = get_tmp_dir(session)
     args = session.posargs or code_locations
     install_with_constraints(
         session,
+        tmp_dir,
         "flake8",
         "flake8-bandit",
         "flake8-black",
@@ -48,8 +67,9 @@ def lint(session):
 
 @nox.session(python="3.6", reuse_venv=True)
 def safety(session):
-    install_with_constraints(session, "safety")
-    with tempfile.NamedTemporaryFile() as requirements:
+    tmp_dir = get_tmp_dir(session)
+    install_with_constraints(session, tmp_dir, "safety")
+    with tempfile.NamedTemporaryFile(dir=tmp_dir) as requirements:
         session.run(
             "poetry",
             "export",