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GroupManager: Use `.setSub()` and parallel queries to avoid races 

This also simplfies the code.
pull/5276/head
Richard Hansen 2021-11-12 21:26:55 -05:00
parent 9d63700da0
commit 5b37a56197
1 changed files with 22 additions and 43 deletions
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65
src/node/db/GroupManager.js
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@ -43,38 +43,27 @@ exports.deleteGroup = async (groupID) => {
}
// iterate through all pads of this group and delete them (in parallel)
await Promise.all(Object.keys(group.pads)
.map((padID) => padManager.getPad(padID)
.then((pad) => pad.remove())
));
await Promise.all(Object.keys(group.pads).map(async (padId) => {
const pad = await padManager.getPad(padId);
await pad.remove();
}));
// iterate through group2sessions and delete all sessions
const group2sessions = await db.get(`group2sessions:${groupID}`);
const sessions = group2sessions ? group2sessions.sessionIDs : {};
// Delete associated sessions in parallel. This should be done before deleting the group2sessions
// record because deleting a session updates the group2sessions record.
const {sessionIDs = {}} = await db.get(`group2sessions:${groupID}`) || {};
await Promise.all(Object.keys(sessionIDs).map(async (sessionId) => {
await sessionManager.deleteSession(sessionId);
}));
// loop through all sessions and delete them (in parallel)
await Promise.all(Object.keys(sessions).map((session) => sessionManager.deleteSession(session)));
await Promise.all([
db.remove(`group2sessions:${groupID}`),
// UeberDB's setSub() method atomically reads the record, updates the appropriate property, and
// writes the result. Setting a property to `undefined` deletes that property (JSON.stringify()
// ignores such properties).
db.setSub('groups', [groupID], undefined),
]);
// remove group2sessions entry
await db.remove(`group2sessions:${groupID}`);
// unlist the group
let groups = await exports.listAllGroups();
groups = groups ? groups.groupIDs : [];
const index = groups.indexOf(groupID);
if (index !== -1) {
// remove from the list
groups.splice(index, 1);
// regenerate group list
const newGroups = {};
groups.forEach((group) => newGroups[group] = 1);
await db.set('groups', newGroups);
}
// remove group entry
// Remove the group record after updating the `groups` record so that the state is consistent.
await db.remove(`group:${groupID}`);
};
@ -86,22 +75,12 @@ exports.doesGroupExist = async (groupID) => {
};
exports.createGroup = async () => {
// search for non existing groupID
const groupID = `g.${randomString(16)}`;
// create the group
await db.set(`group:${groupID}`, {pads: {}});
// list the group
let groups = await exports.listAllGroups();
groups = groups ? groups.groupIDs : [];
groups.push(groupID);
// regenerate group list
const newGroups = {};
groups.forEach((group) => newGroups[group] = 1);
await db.set('groups', newGroups);
// Add the group to the `groups` record after the group's individual record is created so that
// the state is consistent. Note: UeberDB's setSub() method atomically reads the record, updates
// the appropriate property, and writes the result.
await db.setSub('groups', [groupID], 1);
return {groupID};
};