Summary

Remove the concept of credential.

Motivation

Credential intends to carry service credentials like access_key_id and secret_access_key. At OpenDAL, we designed a global Credential enum for services and users to use.

pub enum Credential {
    /// Plain refers to no credential has been provided, fallback to services'
    /// default logic.
    Plain,
    /// Basic refers to HTTP Basic Authentication.
    Basic { username: String, password: String },
    /// HMAC, also known as Access Key/Secret Key authentication.
    HMAC {
        access_key_id: String,
        secret_access_key: String,
    },
    /// Token refers to static API token.
    Token(String),
}

However, every service only supports one kind of Credential with different Credential load methods covered by reqsign. As a result, only HMAC is used. Both users and services need to write the same logic again and again.

Guide-level explanation

Credential will be removed, and the services builder will provide native credential representation directly.

For s3:

pub fn access_key_id(&mut self, v: &str) -> &mut Self {}
pub fn secret_access_key(&mut self, v: &str) -> &mut Self {}

For azblob:

pub fn account_name(&mut self, account_name: &str) -> &mut Self {}
pub fn account_key(&mut self, account_key: &str) -> &mut Self {}

All builders must implement Debug by hand and redact sensitive fields to avoid credentials being a leak.

impl Debug for Builder {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let mut ds = f.debug_struct("Builder");

        ds.field("root", &self.root);
        ds.field("container", &self.container);
        ds.field("endpoint", &self.endpoint);

        if self.account_name.is_some() {
            ds.field("account_name", &"<redacted>");
        }
        if self.account_key.is_some() {
            ds.field("account_key", &"<redacted>");
        }

        ds.finish_non_exhaustive()
    }
}

Reference-level explanation

Simple change without reference-level explanation needs.

Drawbacks

API Breakage.

Rationale and alternatives

None

Prior art

None

Unresolved questions

None

Future possibilities

None