Reimplement config parsing, add integration tests

src/settings.rs

@@ -0,0 +1,67 @@
+// SPDX-FileCopyrightText: © Matteo Settenvini <matteo.settenvini@montecristosoftware.eu>
+// SPDX-License-Identifier: EUPL-1.2
+
+use {anyhow::anyhow, rocket::serde::Deserialize, serde::de::Error};
+
+#[derive(Deserialize)]
+#[serde(crate = "rocket::serde")]
+pub struct Settings {
+    #[serde(deserialize_with = "deserialize_s3_bucket")]
+    pub s3_bucket: s3::Bucket,
+}
+
+fn deserialize_s3_bucket<'de, D>(deserializer: D) -> Result<s3::Bucket, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let config = S3Config::deserialize(deserializer)?;
+    config.try_into().map_err(D::Error::custom)
+}
+
+#[derive(Deserialize)]
+pub struct S3Config {
+    pub name: String,
+    pub endpoint: String,
+    pub region: String,
+
+    #[serde(default)]
+    pub path_style: bool,
+
+    pub access_key_id: String,
+    pub secret_access_key: String,
+}
+
+impl TryInto<s3::Bucket> for S3Config {
+    type Error = anyhow::Error;
+
+    fn try_into(self) -> Result<s3::Bucket, Self::Error> {
+        let region = s3::Region::Custom {
+            region: self.region,
+            endpoint: self.endpoint,
+        };
+
+        let credentials = s3::creds::Credentials::new(
+            Some(&self.access_key_id),
+            Some(&self.secret_access_key),
+            None,
+            None,
+            None,
+        )?;
+
+        log::info!(
+            "Serving contents from bucket {} at {}",
+            &self.name,
+            region.endpoint()
+        );
+
+        let bucket = s3::Bucket::new(&self.name, region, credentials).map_err(|e| anyhow!(e));
+        if self.path_style {
+            bucket.map(|mut b| {
+                b.set_path_style();
+                b
+            })
+        } else {
+            bucket
+        }
+    }
+}