def cancel(operation_id):
# Cancel an operation altogether (only available after pausing)
operation_id = b64decode_id(operation_id)
db = get_db()
operation = db.execute("SELECT * FROM operations WHERE id = ?",
(operation_id, )).fetchone()
if operation and operation["completion"] == "PAUSED":
db.execute(
"""
UPDATE operations
SET completion = ?
WHERE id = ?
""",
("CANCELLED", operation_id),
)
db.commit()
return {"operation_id": b64encode_id(operation_id), "success": True}
elif not operation:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Invalid operation ID",
}
else:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Operation is not paused",
}
def resume(operation_id):
# Resume an operation
operation_id = b64decode_id(operation_id)
db = get_db()
operation = db.execute("SELECT * FROM operations WHERE id = ?",
(operation_id, )).fetchone()
if operation and operation["completion"] == "PAUSED":
# Load the remaining workflow and the result (so far)
with open(operation["workflow_store"]) as f:
workflow = json.load(f)
with open(operation["result_store"], "r") as f:
result = json.load(f)
# Initiate the remaining workflow and pass in the result
# NOTE: The workflow itself is already tappable so pausing after
# this point is also possible
deserialize_chain(workflow).delay(result)
db.execute(
"""
UPDATE operations
SET completion = ?
WHERE id = ?
""",
("IN PROGRESS", operation_id),
)
db.commit()
return {"operation_id": b64encode_id(operation_id), "success": True}
elif not operation:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Invalid operation ID",
}
else:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Operation is not paused",
}
def pause(operation_id):
# Request an operation to pause
operation_id = b64decode_id(operation_id)
db = get_db()
operation = db.execute("SELECT * FROM operations WHERE id = ?",
(operation_id, )).fetchone()
if operation and operation["completion"] == "IN PROGRESS":
"""
Change operation status to "REQUESTING PAUSE" - next time
the `app.tappable.pause_or_continue` task is called - it'll know
it should pause
"""
db.execute(
"""
UPDATE operations
SET completion = ?
WHERE id = ?
""",
("REQUESTING PAUSE", operation_id),
)
db.commit()
return {"operation_id": b64encode_id(operation_id), "success": True}
elif not operation:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Invalid operation ID",
}
else:
return {
"operation_id": b64encode_id(operation_id),
"success": False,
"message": "Operation is no longer in progress",
}
def operation_info(operation_id):
# Get information about an operation by id
operation_id = b64decode_id(operation_id)
db = get_db()
operation = db.execute("SELECT * FROM operations WHERE id = ?",
(operation_id, )).fetchone()
if operation["completion"] == "COMPLETED":
# Load the result from json file if operation is complete
with open(operation["result_store"], "r") as f:
result = json.load(f)
else:
# Otherwise, result should just be an empty string
result = ""
return render_template(
"operations/operation.html",
operation_id=b64encode_id(operation_id),
status=operation["completion"],
result=result,
)
def start():
# Start a csv reading + parsing operation
db = get_db()
# Insert a record of the operation and grab its id
operation_id: int = db.execute(
"INSERT INTO operations (requester_id, completion) VALUES (?, ?)",
(g.user["id"], "IN PROGRESS"),
).lastrowid
"""
Brief description of the operation
----------------------------------
`read_start` initiates reading from the csv file
`read_next`, then continues reading from the same file and
merges its results with the previous read
`read_finish_continue`, determines whether or not the file has been
read in full and continues reading accordingly
Once the iterative reading is finished, `start_parsing` is called
to start the parsing operation
"""
csvpath = os.path.join(app.instance_path, "MOCK_DATA.csv")
# Start the operation, using the usual tappable configuration
tappable(
# Chain of data reading + callback to data parsing
read_start.s(csvpath)
| read_next.s(csvpath)
| read_finish_continue.s(start_parsing.s(operation_id), csvpath,
operation_id),
# Function to check whether or not operation should pause
should_pause.s(operation_id),
# Pause handler
save_state.s(operation_id),
).delay()
db.commit()
return redirect(
url_for("operation_info", operation_id=b64encode_id(operation_id)))