rxdb
Version:
A local-first realtime NoSQL Database for JavaScript applications - https://rxdb.info/
123 lines (119 loc) • 4.13 kB
JavaScript
import { fillFileIfEtagMatches, readJsonFileContent } from "./google-drive-helper.js";
import { newRxError } from "../../rx-error.js";
import { ensureNotFalsy, now, promiseWait } from "../utils/index.js";
import { processWalFile } from "./upstream.js";
export var TRANSACTION_FILE_NAME = 'transaction.json';
export var TRANSACTION_BLOCKED_FLAG = {
retry: true
};
export async function startTransactionTryOnce(googleDriveOptions, init) {
var txFileContent = await readJsonFileContent(googleDriveOptions, init.transactionFile.fileId);
if (!isEmpty(txFileContent.content)) {
// tx already existed -> retry
return TRANSACTION_BLOCKED_FLAG;
}
var newTxContent = {
createdAtClientTime: now()
};
var writeResult = await fillFileIfEtagMatches(googleDriveOptions, init.transactionFile.fileId, txFileContent.etag, newTxContent);
if (writeResult.status !== 200) {
return TRANSACTION_BLOCKED_FLAG;
}
return {
etag: writeResult.etag
};
}
export async function startTransaction(googleDriveOptions, init) {
var current = await startTransactionTryOnce(googleDriveOptions, init);
var attempts = 0;
while (current.retry) {
/**
* Wait a bit.
* Exponential backoff: 100, 200, 400, 800, ...
*/
var waitTime = Math.min(100 * 1000, 100 * Math.pow(1.5, attempts));
await promiseWait(waitTime);
/**
* Check for timeout
*/
var timeoutState = await isTransactionTimedOut(googleDriveOptions, init);
if (timeoutState.expired) {
await fillFileIfEtagMatches(googleDriveOptions, init.transactionFile.fileId, timeoutState.etag, undefined);
}
/**
* Try to get the transaction again
*/
current = await startTransactionTryOnce(googleDriveOptions, init);
attempts = attempts + 1;
}
return current;
}
export async function isTransactionTimedOut(googleDriveOptions, init) {
var request = await fetch(googleDriveOptions.apiEndpoint + '/drive/v3/files/' + init.transactionFile.fileId + '?fields=modifiedTime', {
headers: {
Authorization: 'Bearer ' + googleDriveOptions.authToken
}
});
var data = await request.json();
var dateHeader = request.headers.get('date');
var serverTime = Date.parse(ensureNotFalsy(dateHeader, 'header time'));
var transactionCreation = Date.parse(ensureNotFalsy(data.modifiedTime, 'tx time'));
/**
* By definition the HTTP Date header
* only has seconds precision so if
* the serverTime is "impossible", set it
* to the transaction creation time.
*/
if (serverTime < transactionCreation) {
serverTime = transactionCreation;
}
var transactionAge = serverTime - transactionCreation;
var timeLeft = googleDriveOptions.transactionTimeout - transactionAge;
return {
timeLeft,
transactionAge,
// expired: false
expired: timeLeft <= 0,
etag: ensureNotFalsy(data.etag, 'etag')
};
}
export async function commitTransaction(googleDriveOptions, init, transactionInput) {
if (transactionInput.retry) {
throw newRxError('GDR11', {
args: {
transaction: transactionInput
}
});
}
var transaction = transactionInput;
var writeResult = await fillFileIfEtagMatches(googleDriveOptions, init.transactionFile.fileId, transaction.etag, undefined);
if (writeResult.status !== 200) {
throw newRxError('GDR11', {
args: {
status: writeResult.status,
etag: writeResult.etag
}
});
}
}
function isEmpty(value) {
if (value === undefined || value === null) return true;
if (typeof value === "string") {
return value.length === 0;
}
if (typeof value === "object" && !Array.isArray(value)) {
return Object.keys(value).length === 0;
}
return false;
}
export async function runInTransaction(googleDriveOptions, init, primaryPath, fn, runAfter) {
var transaction = await startTransaction(googleDriveOptions, init);
await processWalFile(googleDriveOptions, init, primaryPath);
var result = await fn();
await commitTransaction(googleDriveOptions, init, transaction);
if (runAfter) {
await runAfter();
}
return result;
}
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