Introduce async operations in webapp (#485)

* Introduce run_async for system processes

* Remove redundant code for system shutdown and reboot endpoints

* Use async process with systemd_service

* Modify innerHTML to show progress messages

* Add docstring

src/web/file_cmds.py

@@ -14,6 +14,7 @@ from ractl_cmds import (
     list_devices,
     reserve_scsi_ids,
 )
+from pi_cmds import run_async
 from socket_cmds import send_pb_command
 from settings import CFG_DIR, CONFIG_FILE_SUFFIX, PROPERTIES_SUFFIX, RESERVATIONS
 import rascsi_interface_pb2 as proto
@@ -175,42 +176,42 @@ def unzip_file(file_name, member=False, members=False):
     members contains all of the full paths to each of the zip archive members
     Returns (dict) with (boolean) status and (list of str) msg
     """
-    from subprocess import run
-    from re import escape
+    from asyncio import run
     server_info = get_server_info()
     prop_flag = False
 
     if not member:
-        unzip_proc = run(
-            ["unzip", "-d", server_info["image_dir"], "-n", "-j", \
-                f"{server_info['image_dir']}/{file_name}"], capture_output=True
-            )
+        unzip_proc = run(run_async(
+            f"unzip -d {server_info['image_dir']} -n -j "
+            f"{server_info['image_dir']}/{file_name}"
+            ))
         for path in members:
             if path.endswith(PROPERTIES_SUFFIX):
                 name = PurePath(path).name
                 rename_file(f"{server_info['image_dir']}/{name}", f"{CFG_DIR}/{name}")
                 prop_flag = True
     else:
-        unzip_proc = run(
-            ["unzip", "-d", server_info["image_dir"], "-n", "-j", \
-                f"{server_info['image_dir']}/{file_name}", escape(member)], capture_output=True
-            )
+        from re import escape
+        member = escape(member)
+        unzip_proc = run(run_async(
+            f"unzip -d {server_info['image_dir']} -n -j "
+            f"{server_info['image_dir']}/{file_name} {member}"
+            ))
         # Attempt to unzip a properties file in the same archive dir
-        unzip_prop = run(
-            ["unzip", "-d", CFG_DIR, "-n", "-j", \
-                f"{server_info['image_dir']}/{file_name}", escape(member) + "." + PROPERTIES_SUFFIX], capture_output=False
-            )
-        if unzip_prop.returncode == 0:
+        unzip_prop = run(run_async(
+            f"unzip -d {CFG_DIR} -n -j "
+            f"{server_info['image_dir']}/{file_name} {member}.{PROPERTIES_SUFFIX}"
+            ))
+        if unzip_prop["returncode"] == 0:
             prop_flag = True
-    if unzip_proc.returncode != 0:
-        stderr = unzip_proc.stderr.decode("utf-8")
-        logging.warning("Unzipping failed: %s", stderr)
-        return {"status": False, "msg": stderr}
+    if unzip_proc["returncode"] != 0:
+        logging.warning("Unzipping failed: %s", unzip_proc["stderr"])
+        return {"status": False, "msg": unzip_proc["stderr"]}
 
     from re import findall
     unzipped = findall(
         "(?:inflating|extracting):(.+)\n",
-        unzip_proc.stdout.decode("utf-8")
+        unzip_proc["stdout"]
         )
     return {"status": True, "msg": unzipped, "prop_flag": prop_flag}
 
@@ -404,7 +405,6 @@ def write_drive_properties(file_name, conf):
         return {"status": False, "msg": f"Could not write to file: {file_path}"}
 
 
-
 def read_drive_properties(path_name):
     """
     Reads drive properties from json formatted file.

src/web/pi_cmds.py

@@ -3,6 +3,8 @@ Module for methods controlling and getting information about the Pi's Linux syst
 """
 
 import subprocess
+import asyncio
+import logging
 from settings import AUTH_GROUP
 
 
@@ -11,10 +13,8 @@ def systemd_service(service, action):
     Takes (str) service and (str) action
     Action can be one of start/stop/restart
     """
-    return (
-        subprocess.run(["sudo", "/bin/systemctl", action, service]).returncode
-        == 0
-    )
+    proc = asyncio.run(run_async("sudo /bin/systemctl {action} {service}"))
+    return proc["returncode"] == 0
 
 
 def reboot_pi():
@@ -119,6 +119,30 @@ def introspect_file(file_path, re_term):
     return False
 
 
+async def run_async(cmd):
+    """
+    Takes (str) cmd with the shell command to execute
+    Executes shell command and captures output
+    Returns (dict) with (int) returncode, (str) stdout, (str) stderr
+    """
+    proc = await asyncio.create_subprocess_shell(
+        cmd,
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE)
+
+    stdout, stderr = await proc.communicate()
+
+    logging.info("Executed command \"%s\" with status code %d", cmd, proc.returncode)
+    if stdout:
+        stdout = stdout.decode()
+        logging.info("stdout: %s", stdout)
+    if stderr:
+        stderr = stderr.decode()
+        logging.info("stderr: %s", stderr)
+
+    return {"returncode": proc.returncode, "stdout": stdout, "stderr": stderr}
+
+
 def auth_active():
     """
     Inspects if the group defined in AUTH_GROUP exists on the system.
@@ -132,4 +156,4 @@ def auth_active():
                 "status": True,
                 "msg": "You must log in to use this function!",
                 }
-    return {"status": False, "msg": ""}
+    return {"status": False, "msg": ""}

src/web/templates/base.html

@@ -59,7 +59,7 @@
         </tbody>
     </table>
     </div>
-    <div class="flash">
+    <div class="flash" id="flash">
         {% for category, message in get_flashed_messages(with_categories=true) %}
         {% if category == "stdout" or category == "stderr" %}
         <pre>{{ message }}</pre>

src/web/templates/index.html

@@ -201,7 +201,7 @@
                             <form action="/files/unzip" method="post">
                                 <input name="zip_file" type="hidden" value="{{ file['name'] }}">
                                 <input name="zip_member" type="hidden" value="{{ member }}">
-                                <input type="submit" value="Unzip">
+                                <input type="submit" value="Unzip" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Unzipping single file...</div>"'>
                             </form>
                             </summary>
                             <ul style="list-style: none;">
@@ -215,7 +215,7 @@
                             <form action="/files/unzip" method="post">
                                 <input name="zip_file" type="hidden" value="{{ file['name'] }}">
                                 <input name="zip_member" type="hidden" value="{{ member }}">
-                                <input type="submit" value="Unzip">
+                                <input type="submit" value="Unzip" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Unzipping single file...</div>"'>
                             </form>
                             {% endif %}
                         </li>
@@ -243,7 +243,7 @@
                 <form action="/files/unzip" method="post">
                     <input name="zip_file" type="hidden" value="{{ file['name'] }}">
                     <input name="zip_members" type="hidden" value="{{ file['zip_members'] }}">
-                    <input type="submit" value="Unzip All">
+                    <input type="submit" value="Unzip All" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Unzipping all files...</div>"'>
                 </form>
                 {% else %}
                 <form action="/scsi/attach" method="post">
@@ -388,7 +388,7 @@
             <form action="/files/download_to_images" method="post">
                 <label for="url">URL:</label>
                 <input name="url" placeholder="URL" required="" type="url">
-                <input type="submit" value="Download">
+                <input type="submit" value="Download" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Downloading File to Images...</div>"'>
             </form>
         </td>
     </tr>
@@ -415,7 +415,7 @@
             <form action="/files/download_to_afp" method="post">
                 <label for="url">URL:</label>
                 <input name="url" placeholder="URL" required="" type="url">
-                <input type="submit" value="Download">
+                <input type="submit" value="Download" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Downloading File to AppleShare...</div>"'>
             </form>
         </td>
     </tr>
@@ -458,7 +458,7 @@
                 </select>
                 <label for="url">URL:</label>
                 <input name="url" placeholder="URL" required="" type="url">
-                <input type="submit" value="Download and Mount ISO">
+                <input type="submit" value="Download and Mount ISO" onclick='document.getElementById("flash").innerHTML = "<div class=\"message\">Downloading File as ISO...</div>"'>
             </form>
         </td>
     </tr>

src/web/web.py

@@ -695,9 +695,6 @@ def restart():
         flash(auth["msg"], "error")
         return redirect(url_for("index"))
 
-    detach_all()
-    flash("Safely detached all devices.")
-    flash("Rebooting the Pi momentarily...")
     reboot_pi()
     return redirect(url_for("index"))
 
@@ -730,9 +727,6 @@ def shutdown():
         flash(auth["msg"], "error")
         return redirect(url_for("index"))
 
-    detach_all()
-    flash("Safely detached all devices.")
-    flash("Shutting down the Pi momentarily...")
     shutdown_pi()
     return redirect(url_for("index"))
 
@@ -940,7 +934,7 @@ def delete():
 @APP.route("/files/unzip", methods=["POST"])
 def unzip():
     """
-    Unzips a specified zip file
+    Unzips all files in a specified zip archive, or a single file in the zip archive
     """
     auth = auth_active()
     if auth["status"] and "username" not in session: