Add ability to download assignments

download.yml

@@ -0,0 +1,26 @@
+---
+- hosts: jupyterhub_host
+  vars_files:
+    - ['secrets.yml', 'secrets.vault.yml']
+    - ['users.yml', 'users.vault.yml']
+    - ['vars.local.yml', 'vars.yml']
+
+  vars_prompt:
+    assignment: "Which assignment?"
+
+  tasks:
+    - name: collect submissions
+      collect_submissions:
+        src: '.nbgrader/submissions/{{ assignment }}.tar.gz'
+        dest: '/srv/assignments/submissions.tar.gz'
+        users: "{{ instructors }}"
+        overwrite: yes
+      sudo: yes
+
+    - name: download submissions
+      fetch:
+        src: '/srv/assignments/submissions.tar.gz'
+        dest: '{{ assignment_path }}/{{ assignment }}/submissions.tar.gz'
+        flat: yes
+        fail_on_missing: yes
+      sudo: yes

library/collect_submissions.py

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+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+import os
+import tarfile
+
+def main():
+    module = AnsibleModule(
+        argument_spec={
+            'src': dict(required=True),
+            'dest': dict(required=True),
+            'users': dict(required=True, type='list'),
+            'overwrite': dict(default=False, type='bool')
+        }
+    )
+
+    src = module.params["src"]
+    dest = module.params["dest"]
+    users = module.params["users"]
+    overwrite = module.params["overwrite"]
+
+    if os.path.exists(dest) and not overwrite:
+        module.exit_json(changed=False)
+    elif os.path.exists(dest):
+        os.remove(dest)
+
+    tf = tarfile.open(dest, 'w:gz')
+
+    for user in users:
+        homedir = os.path.abspath('/home/{}'.format(user))
+        if not homedir.startswith('/home/'):
+            tf.close()
+            os.remove(dest)
+            module.fail_json(msg="Home directory is invalid: {}".format(homedir))
+        if not os.path.exists(homedir):
+            tf.close()
+            os.remove(dest)
+            module.fail_json(msg="Home directory does not exist: {}".format(homedir))
+
+        pth = os.path.join(homedir, src)
+        if not os.path.exists(pth):
+            continue
+
+        tf.add(pth, arcname="{}.tar.gz".format(user))
+
+    tf.close()
+
+    module.exit_json(changed=True)
+
+
+from ansible.module_utils.basic import *
+main()

script/download

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+#!/bin/bash
+
+ROOT=$(dirname $0)/..
+
+if [ ! -e ${ROOT}//inventory ]; then
+  echo "Please create an inventory file with your hosts."
+  echo " cp inventory.example inventory"
+  exit 1
+fi
+
+if [ -e ${ROOT}/secrets.yml ]; then
+  VAULT_ARG=
+else
+  VAULT_ARG=--ask-vault-pass
+fi
+
+exec ansible-playbook ${ROOT}/download.yml -i ${ROOT}/inventory ${VAULT_ARG} $@