Add possibility to specify credentials for S3 explicitly

Author: Saruniks

docs/Configuration.md

@@ -92,6 +92,8 @@ endpoint = "s3-us-east-1.amazonaws.com"
 use_ssl = true
 key_prefix = "s3prefix"
 server_side_encryption = false
+access_key_id = "aws_access_key_id"
+secret_access_key = "aws_secret_access_key"
 
 [cache.webdav]
 endpoint = "http://192.168.10.42:80/some/webdav.php"
@@ -150,6 +152,8 @@ configuration variables
 * `SCCACHE_REGION` s3 region, required if using AWS S3
 * `SCCACHE_S3_USE_SSL` s3 endpoint requires TLS, set this to `true`
 * `SCCACHE_S3_KEY_PREFIX` s3 key prefix (optional)
+* `SCCACHE_AWS_ACCESS_KEY_ID` AWS access key (optional). If not specified, sccache will attempt to load credentials from other sources (see [S3 credentials](S3.md#credentials))
+* `SCCACHE_AWS_SECRET_ACCESS_KEY` AWS secret key (optional). If not specified, sccache will attempt to load credentials from other sources (see [S3 credentials](S3.md#credentials))
 
 The endpoint used then becomes `${SCCACHE_BUCKET}.s3-{SCCACHE_REGION}.amazonaws.com`.
 If you are not using the default endpoint and `SCCACHE_REGION` is undefined, it

docs/S3.md

@@ -23,7 +23,9 @@ Cloudflare R2 is an S3-compatible object storage and works with the same configu
 
 ## Credentials
 
-Sccache is able to load credentials from various sources. Including:
+You can specify credentials using environment variables (`SCCACHE_AWS_ACCESS_KEY_ID` and `SCCACHE_AWS_SECRET_ACCESS_KEY`) or [file configuration](Configuration.md#file) (`access_key_id` and `secret_access_key`).
+
+If credentials are not specified, sccache will attempt to load credentials from various other sources, including:
 
 - Static: `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`.
 - Profile: `~/.aws/credentials` and `~/.aws/config`. The AWS_PROFILE environment variable can be used to select a specific profile if multiple profiles are available.

src/cache/cache.rs

@@ -680,6 +680,8 @@ pub fn storage_from_config(
                     c.endpoint.as_deref(),
                     c.use_ssl,
                     c.server_side_encryption,
+                    c.access_key_id.as_deref(),
+                    c.secret_access_key.as_deref(),
                 )
                 .map_err(|err| anyhow!("create s3 cache failed: {err:?}"))?;
 

src/cache/s3.rs

@@ -21,6 +21,7 @@ use crate::errors::*;
 pub struct S3Cache;
 
 impl S3Cache {
+    #[allow(clippy::too_many_arguments)]
     pub fn build(
         bucket: &str,
         region: Option<&str>,
@@ -29,12 +30,22 @@ impl S3Cache {
         endpoint: Option<&str>,
         use_ssl: Option<bool>,
         server_side_encryption: Option<bool>,
+        access_key_id: Option<&str>,
+        secret_access_key: Option<&str>,
     ) -> Result<Operator> {
         let mut builder = S3::default();
         builder.http_client(set_user_agent());
         builder.bucket(bucket);
         builder.root(key_prefix);
 
+        if let Some(access_key_id) = access_key_id {
+            builder.access_key_id(access_key_id);
+        }
+
+        if let Some(secret_access_key) = secret_access_key {
+            builder.secret_access_key(secret_access_key);
+        }
+
         if let Some(region) = region {
             builder.region(region);
         }

src/config.rs

@@ -315,6 +315,8 @@ pub struct S3CacheConfig {
     pub endpoint: Option<String>,
     pub use_ssl: Option<bool>,
     pub server_side_encryption: Option<bool>,
+    pub access_key_id: Option<String>,
+    pub secret_access_key: Option<String>,
 }
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -640,6 +642,8 @@ fn config_from_env() -> Result<EnvConfig> {
         let server_side_encryption = bool_from_env_var("SCCACHE_S3_SERVER_SIDE_ENCRYPTION")?;
         let endpoint = env::var("SCCACHE_ENDPOINT").ok();
         let key_prefix = key_prefix_from_env_var("SCCACHE_S3_KEY_PREFIX");
+        let access_key_id = env::var("SCCACHE_AWS_ACCESS_KEY_ID").ok();
+        let secret_access_key = env::var("SCCACHE_AWS_SECRET_ACCESS_KEY").ok();
 
         Some(S3CacheConfig {
             bucket,
@@ -649,14 +653,18 @@ fn config_from_env() -> Result<EnvConfig> {
             endpoint,
             use_ssl,
             server_side_encryption,
+            access_key_id,
+            secret_access_key,
         })
     } else {
         None
     };
 
     if s3.as_ref().map(|s3| s3.no_credentials).unwrap_or_default()
         && (env::var_os("AWS_ACCESS_KEY_ID").is_some()
-            || env::var_os("AWS_SECRET_ACCESS_KEY").is_some())
+            || env::var_os("AWS_SECRET_ACCESS_KEY").is_some()
+            || env::var_os("SCCACHE_AWS_ACCESS_KEY_ID").is_some()
+            || env::var_os("SCCACHE_AWS_SECRET_ACCESS_KEY").is_some())
     {
         bail!("If setting S3 credentials, SCCACHE_S3_NO_CREDENTIALS must not be set.");
     }
@@ -1309,7 +1317,27 @@ fn config_overrides() {
 
 #[test]
 #[serial]
-fn test_s3_no_credentials_conflict() {
+fn test_s3_no_credentials_conflict_0() {
+    env::set_var("SCCACHE_S3_NO_CREDENTIALS", "true");
+    env::set_var("SCCACHE_BUCKET", "my-bucket");
+    env::set_var("SCCACHE_AWS_ACCESS_KEY_ID", "aws-access-key-id");
+    env::set_var("SCCACHE_AWS_SECRET_ACCESS_KEY", "aws-secret-access-key");
+
+    let error = config_from_env().unwrap_err();
+    assert_eq!(
+        "If setting S3 credentials, SCCACHE_S3_NO_CREDENTIALS must not be set.",
+        error.to_string()
+    );
+
+    env::remove_var("SCCACHE_S3_NO_CREDENTIALS");
+    env::remove_var("SCCACHE_BUCKET");
+    env::remove_var("SCCACHE_AWS_ACCESS_KEY_ID");
+    env::remove_var("SCCACHE_AWS_SECRET_ACCESS_KEY");
+}
+
+#[test]
+#[serial]
+fn test_s3_no_credentials_conflict_1() {
     env::set_var("SCCACHE_S3_NO_CREDENTIALS", "true");
     env::set_var("SCCACHE_BUCKET", "my-bucket");
     env::set_var("AWS_ACCESS_KEY_ID", "aws-access-key-id");
@@ -1479,8 +1507,10 @@ region = "us-east-2"
 endpoint = "s3-us-east-1.amazonaws.com"
 use_ssl = true
 key_prefix = "s3prefix"
-no_credentials = true
+no_credentials = false
 server_side_encryption = false
+access_key_id = "some_access_key_id"
+secret_access_key = "some_secret_access_key"
 
 [cache.webdav]
 endpoint = "http://127.0.0.1:8080"
@@ -1543,8 +1573,10 @@ no_credentials = true
                     endpoint: Some("s3-us-east-1.amazonaws.com".to_owned()),
                     use_ssl: Some(true),
                     key_prefix: "s3prefix".into(),
-                    no_credentials: true,
-                    server_side_encryption: Some(false)
+                    no_credentials: false,
+                    server_side_encryption: Some(false),
+                    access_key_id: Some("some_access_key_id".to_owned()),
+                    secret_access_key: Some("some_secret_access_key".to_owned()),
                 }),
                 webdav: Some(WebdavCacheConfig {
                     endpoint: "http://127.0.0.1:8080".to_string(),