import { ApiError } from 'app/common/ApiError';
import { Document } from 'app/gen-server/entity/Document';
import { Workspace } from 'app/gen-server/entity/Workspace';
import { HomeDBManager, Scope } from 'app/gen-server/lib/HomeDBManager';
import { fromNow } from 'app/gen-server/sqlUtils';
import { getAuthorizedUserId } from 'app/server/lib/Authorizer';
import { expressWrap } from 'app/server/lib/expressWrap';
import { GristServer } from 'app/server/lib/GristServer';
import { IElectionStore } from 'app/server/lib/IElectionStore';
import log from 'app/server/lib/log';
import { IPermitStore } from 'app/server/lib/Permit';
import { optStringParam, stringParam } from 'app/server/lib/requestUtils';
import * as express from 'express';
import fetch from 'node-fetch';
import * as Fetch from 'node-fetch';
const HOUSEKEEPER_PERIOD_MS = 1 * 60 * 60 * 1000; // operate every 1 hour
const AGE_THRESHOLD_OFFSET = '-30 days'; // should be an interval known by postgres + sqlite
/**
* Take care of periodic tasks:
*
* - deleting old soft-deleted documents
* - deleting old soft-deleted workspaces
*
* Call start(), keep the object around, and call stop() when shutting down.
*
* Some care is taken to elect a single server to do the housekeeping, so if there are
* multiple home servers, there will be no competition or duplication of effort.
*/
export class Housekeeper {
private _interval?: NodeJS.Timeout;
private _electionKey?: string;
public constructor(private _dbManager: HomeDBManager, private _server: GristServer,
private _permitStore: IPermitStore, private _electionStore: IElectionStore) {
}
/**
* Start a ticker to launch housekeeping tasks from time to time.
*/
public async start() {
await this.stop();
this._interval = setInterval(() => this.deleteTrashExclusively().catch(log.warn.bind(log)), HOUSEKEEPER_PERIOD_MS);
}
/**
* Stop scheduling housekeeping tasks. Note: doesn't wait for any housekeeping task in progress.
*/
public async stop() {
if (this._interval) {
clearInterval(this._interval);
this._interval = undefined;
}
}
/**
* Deletes old trash if no other server is working on it or worked on it recently.
*/
public async deleteTrashExclusively(): Promise<boolean> {
const electionKey = await this._electionStore.getElection('trash', HOUSEKEEPER_PERIOD_MS / 2.0);
if (!electionKey) {
log.info('Skipping deleteTrash since another server is working on it or worked on it recently');
return false;
}
this._electionKey = electionKey;
await this.deleteTrash();
return true;
}
/**
* Deletes old trash regardless of what other servers may be doing.
*/
public async deleteTrash() {
// Delete old soft-deleted docs
const docs = await this._getDocsToDelete();
for (const doc of docs) {
// Last minute check - is the doc really soft-deleted?
if (doc.removedAt === null && doc.workspace.removedAt === null) {
throw new Error(`attempted to hard-delete a document that was not soft-deleted: ${doc.id}`);
}
// In general, documents can only be manipulated with the coordination of the
// document worker to which they are assigned. For an old soft-deleted doc,
// we could probably get away with ensuring the document is closed/unloaded
// and then deleting it without ceremony. But, for consistency, and because
// it will be useful for other purposes, we work through the api using special
// temporary permits.
const permitKey = await this._permitStore.setPermit({docId: doc.id});
try {
const result = await fetch(await this._server.getHomeUrlByDocId(doc.id, `/api/docs/${doc.id}`), {
method: 'DELETE',
headers: {
Permit: permitKey
}
});
if (result.status !== 200) {
log.error(`failed to delete document ${doc.id}: error status ${result.status}`);
}
} finally {
await this._permitStore.removePermit(permitKey);
}
}
// Delete old soft-deleted workspaces
const workspaces = await this._getWorkspacesToDelete();
// Note: there's a small chance a workspace could be undeleted right under the wire,
// and a document added, in which case the method we call here would not yet clean
// up the docs in s3. TODO: deal with this.
for (const workspace of workspaces) {
// Last minute check - is the workspace really soft-deleted?
if (workspace.removedAt === null) {
throw new Error(`attempted to hard-delete a workspace that was not soft-deleted: ${workspace.id}`);
}
const scope: Scope = {
userId: this._dbManager.getPreviewerUserId(),
specialPermit: {
workspaceId: workspace.id
}
};
await this._dbManager.deleteWorkspace(scope, workspace.id);
}
}
public addEndpoints(app: express.Application) {
// Allow support user to perform housekeeping tasks for a specific
// document. The tasks necessarily bypass user access controls.
// As such, it would be best if these endpoints not offer ways to
// read or write the content of a document.
// Remove unlisted snapshots that are not recorded in inventory.
// Once all such snapshots have been removed, there should be no
// further need for this endpoint.
app.post('/api/housekeeping/docs/:docId/snapshots/clean', this._withSupport(async (_req, docId, headers) => {
const url = await this._server.getHomeUrlByDocId(docId, `/api/docs/${docId}/snapshots/remove`);
return fetch(url, {
method: 'POST',
body: JSON.stringify({ select: 'unlisted' }),
headers,
});
}));
// Remove action history from document. This may be of occasional
// use, for allowing support to help users looking to purge some
// information that leaked into document history that they'd
// prefer not be there, until there's an alternative.
app.post('/api/housekeeping/docs/:docId/states/remove', this._withSupport(async (_req, docId, headers) => {
const url = await this._server.getHomeUrlByDocId(docId, `/api/docs/${docId}/states/remove`);
return fetch(url, {
method: 'POST',
body: JSON.stringify({ keep: 1 }),
headers,
});
}));
// Force a document to reload. Can be useful during administrative
// actions.
app.post('/api/housekeeping/docs/:docId/force-reload', this._withSupport(async (_req, docId, headers) => {
const url = await this._server.getHomeUrlByDocId(docId, `/api/docs/${docId}/force-reload`);
return fetch(url, {
method: 'POST',
headers,
});
}));
// Move a document to its assigned worker. Can be useful during administrative
// actions.
//
// Optionally accepts a `group` query param for updating the document's group prior
// to moving. A blank string unsets the current group, if any. This is useful for controlling
// which worker group the document is assigned a worker from.
app.post('/api/housekeeping/docs/:docId/assign', this._withSupport(async (req, docId, headers) => {
const url = new URL(await this._server.getHomeUrlByDocId(docId, `/api/docs/${docId}/assign`));
const group = optStringParam(req.query.group);
if (group !== undefined) { url.searchParams.set('group', group); }
return fetch(url.toString(), {
method: 'POST',
headers,
});
}, 'assign-doc'));
}
/**
* For test purposes, removes any exclusive lock on housekeeping.
*/
public async testClearExclusivity(): Promise<void> {
if (this._electionKey) {
await this._electionStore.removeElection('trash', this._electionKey);
this._electionKey = undefined;
}
}
private async _getDocsToDelete() {
const docs = await this._dbManager.connection.createQueryBuilder()
.select('docs')
.from(Document, 'docs')
.leftJoinAndSelect('docs.workspace', 'workspaces')
.where(`COALESCE(docs.removed_at, workspaces.removed_at) <= ${this._getThreshold()}`)
// the following has no effect (since null <= date is false) but added for clarity
.andWhere('COALESCE(docs.removed_at, workspaces.removed_at) IS NOT NULL')
.getMany();
return docs;
}
private async _getWorkspacesToDelete() {
const docs = await this._dbManager.connection.createQueryBuilder()
.select('workspaces')
.from(Workspace, 'workspaces')
.leftJoin('workspaces.docs', 'docs')
.where(`workspaces.removed_at <= ${this._getThreshold()}`)
// the following has no effect (since null <= date is false) but added for clarity
.andWhere('workspaces.removed_at IS NOT NULL')
// wait for workspace to be empty
.andWhere('docs.id IS NULL')
.getMany();
return docs;
}
/**
* TypeORM isn't very adept at handling date representation for
* comparisons, so we construct the threshold date in SQL so that we
* don't have to deal with its caprices.
*/
private _getThreshold() {
return fromNow(this._dbManager.connection.driver.options.type, AGE_THRESHOLD_OFFSET);
}
// Call a document endpoint with a permit, cleaning up after the call.
// Checks that the user is the support user.
private _withSupport(
callback: (req: express.Request, docId: string, headers: Record<string, string>) => Promise<Fetch.Response>,
permitAction?: string,
): express.RequestHandler {
return expressWrap(async (req, res) => {
const userId = getAuthorizedUserId(req);
if (userId !== this._dbManager.getSupportUserId()) {
throw new ApiError('access denied', 403);
}
const docId = stringParam(req.params.docId, 'docId');
const permitKey = await this._permitStore.setPermit({docId, action: permitAction});
try {
const result = await callback(req, docId, {
Permit: permitKey,
'Content-Type': 'application/json',
});
res.status(result.status);
// Return JSON result, or an empty object if no result provided.
res.json(await result.json().catch(() => ({})));
} finally {
await this._permitStore.removePermit(permitKey);
}
});
}
}