feat(credential-provider-ini): add ignoreCache option

[siddsriv]

Issue

#3396

Description

Exposes the ignoreCache option for fromIni credential provider.

To note, if you run a test script using the fromIni credential provider (loading credentials from the ~/.aws/credentials file) separately each time, the Node.js process starts fresh each time, so there's no cached state between runs. But, if you modify the credentials file within the same running process, we can see the caching in effect - the credentials wouldn't update even after waiting for a while.

The exposed option ignoreCache will allow uncached/refreshed credentials from the credentials file to be used, even if the credentials file is modified within the same running process.

Testing

credential-provider-ini package updated tests

✓ src/fromIni.spec.ts (7)
 ✓ src/resolveAssumeRoleCredentials.spec.ts (23)
 ✓ src/resolveCredentialSource.spec.ts (4)
 ✓ src/resolveProcessCredentials.spec.ts (14)
 ✓ src/resolveProfileData.spec.ts (7)
 ✓ src/resolveSsoCredentials.spec.ts (9)
 ✓ src/resolveStaticCredentials.spec.ts (16)
 ✓ src/resolveWebIdentityCredentials.spec.ts (16)

 Test Files  8 passed (8)
      Tests  96 passed (96)
.
.

Additional context

Short test script to see this option in action:

import { fromIni } from "@aws-sdk/credential-provider-ini";
import { writeFileSync } from "fs";
import { homedir } from "os";
import { resolve } from "path";

const AWS_CREDENTIALS = resolve(`${homedir}/.aws/credentials`);

const getCredentials = async (ignoreCache = false) => {
  const credentials = await fromIni({ ignoreCache })();
  console.log(new Date().toISOString(), credentials);
};

// Test with caching (default behavior)
console.log("With caching:");
await getCredentials(false);

// Modify credentials file
const newCredentials = `
[default]
aws_access_key_id = hello
aws_secret_access_key = hi
`;

console.log("\nModifying credentials file...");
writeFileSync(AWS_CREDENTIALS, newCredentials);

// Test immediate read with caching
console.log("\nImmediate read with caching:");
await getCredentials(false);

// Test immediate read without caching
console.log("\nImmediate read without caching:");
await getCredentials(true);

Output:

% node creds-uncached.mjs
With caching:
2025-01-30T18:29:05.766Z {
  accessKeyId: 'foo',
  secretAccessKey: 'bar',
  sessionToken: undefined,
  '$source': { CREDENTIALS_PROFILE: 'n' }
}

Modifying credentials file...

Immediate read with caching:
2025-01-30T18:29:05.768Z {
  accessKeyId: 'foo',
  secretAccessKey: 'bar',
  sessionToken: undefined,
  '$source': { CREDENTIALS_PROFILE: 'n' }
}

Immediate read without caching:
2025-01-30T18:29:05.768Z {
  accessKeyId: 'hello',
  secretAccessKey: 'hi',
  sessionToken: undefined,
  '$source': { CREDENTIALS_PROFILE: 'n' }
}

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[kuhe]

why is this preferred?

[siddsriv]

no need to have the .ini file at all in that case (no filesystem operations), credentials obtained from STS directly