taler/wallet-core
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make db file writes atomic

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This commit is contained in:
Florian Dold 2020-09-06 16:26:27 +05:30
parent e0c10a06b1
commit 9cb0409cfd
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GPG Key ID: D2E4F00F29D02A4B
1 changed files with 26 additions and 3 deletions
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29
packages/taler-wallet-core/src/headless/helpers.ts
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@ -58,6 +58,20 @@ export interface DefaultNodeWalletArgs {
httpLib?: HttpRequestLibrary;
}
/**
* Generate a random alphanumeric ID. Does *not* use cryptographically
* secure randomness.
*/
function makeId(length: number): string {
let result = "";
const characters =
"abcdefghijklmnopqrstuvwxyz0123456789";
for (let i = 0; i < length; i++) {
result += characters.charAt(Math.floor(Math.random() * characters.length));
}
return result;
}
/**
* Get a wallet instance with default settings for node.
*/
@ -77,7 +91,13 @@ export async function getDefaultNodeWallet(
const dbContent = JSON.parse(dbContentStr);
myBackend.importDump(dbContent);
} catch (e) {
logger.warn("could not read wallet file");
const code: string = e.code;
if (code === "ENOENT") {
logger.trace("wallet file doesn't exist yet");
} else {
logger.error("could not open wallet database file");
throw e;
}
}
myBackend.afterCommitCallback = async () => {
@ -85,10 +105,13 @@ export async function getDefaultNodeWallet(
if (args.persistentStoragePath === undefined) {
return;
}
const tmpPath = `${args.persistentStoragePath}-${makeId(5)}.tmp`;
const dbContent = myBackend.exportDump();
fs.writeFileSync(storagePath, JSON.stringify(dbContent, undefined, 2), {
fs.writeFileSync(tmpPath, JSON.stringify(dbContent, undefined, 2), {
encoding: "utf-8",
});
// Atomically move the temporary file onto the DB path.
fs.renameSync(tmpPath, args.persistentStoragePath);
};
}
@ -106,7 +129,7 @@ export async function getDefaultNodeWallet(
const myVersionChange = (): Promise<void> => {
logger.error("version change requested, should not happen");
throw Error();
throw Error("BUG: wallet DB version change event can't happen with memory IDB");
};
shimIndexedDB(myBridgeIdbFactory);