S3: Add GCS support

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## [unreleased]
 ### Added
+- Add GCS support to S3 backend
 ### Changed
 - Fixed docs refering to github in s3 backend
 ### Removed

README.md

@@ -54,7 +54,7 @@ fn update() -> Result<(), Box<::std::error::Error>> {
 Run the above example to see `self_update` in action: `cargo run --example github --features "archive-tar compression-flate2"`.
 There's also an equivalent example for gitlab: `cargo run --example gitlab --features "archive-tar compression-flate2"`.
 
-Amazon S3 and DigitalOcean Spaces are also supported through the `S3` backend to check for new releases. Provided a `bucket_name`
+Amazon S3, Google GCS, and DigitalOcean Spaces are also supported through the `S3` backend to check for new releases. Provided a `bucket_name`
 and `asset_prefix` string, `self_update` will look up all matching files using the following format
 as a convention for the filenames: `[directory/]<asset name>-<semver>-<platform/target>.<extension>`.
 Leading directories will be stripped from the file name allowing the use of subdirectories in the S3 bucket,

src/backends/s3.rs

@@ -20,10 +20,11 @@ const MAX_KEYS: u8 = 100;
 
 /// The service end point.
 ///
-/// Currently S3 and DigitalOcean Spaces supported.
+/// Currently S3, GCS, and DigitalOcean Spaces supported.
 #[derive(Clone, Copy, Debug)]
 pub enum EndPoint {
     S3,
+    GCS,
     DigitalOceanSpaces,
 }
 
@@ -83,11 +84,7 @@ impl ReleaseListBuilder {
             } else {
                 bail!(Error::Config, "`bucket_name` required")
             },
-            region: if let Some(ref region) = self.region {
-                region.to_owned()
-            } else {
-                bail!(Error::Config, "`region` required")
-            },
+            region: self.region.clone(),
             asset_prefix: self.asset_prefix.clone(),
             target: self.target.clone(),
         })
@@ -102,7 +99,7 @@ pub struct ReleaseList {
     bucket_name: String,
     asset_prefix: Option<String>,
     target: Option<String>,
-    region: String,
+    region: Option<String>,
 }
 
 impl ReleaseList {
@@ -334,11 +331,7 @@ impl UpdateBuilder {
             } else {
                 bail!(Error::Config, "`bucket_name` required")
             },
-            region: if let Some(ref region) = self.region {
-                region.to_owned()
-            } else {
-                bail!(Error::Config, "`region` required")
-            },
+            region: self.region.clone(),
             asset_prefix: self.asset_prefix.clone(),
             target: self
                 .target
@@ -378,7 +371,7 @@ pub struct Update {
     bucket_name: String,
     asset_prefix: Option<String>,
     target: String,
-    region: String,
+    region: Option<String>,
     current_version: String,
     target_version: Option<String>,
     bin_name: String,
@@ -498,33 +491,44 @@ impl ReleaseUpdate for Update {
 fn fetch_releases_from_s3(
     end_point: EndPoint,
     bucket_name: &str,
-    region: &str,
+    region: &Option<String>,
     asset_prefix: &Option<String>,
 ) -> Result<Vec<Release>> {
     let prefix = match asset_prefix {
         Some(prefix) => format!("&prefix={}", prefix),
         None => "".to_string(),
     };
-    let api_url = match end_point {
-        EndPoint::S3 => format!(
-            "https://{}.s3.amazonaws.com/?list-type=2&max-keys={}{}",
-            bucket_name, MAX_KEYS, prefix
-        ),
-        EndPoint::DigitalOceanSpaces => format!(
-            "https://{}.{}.digitaloceanspaces.com/?list-type=2&max-keys={}{}",
-            bucket_name, region, MAX_KEYS, prefix
-        ),
-    };
-
-    debug!("using api url: {:?}", api_url);
 
     let download_base_url = match end_point {
-        EndPoint::S3 => format!("https://{}.s3.{}.amazonaws.com/", bucket_name, region),
+        EndPoint::S3 => {
+            let region = if let Some(region) = region {
+                region
+            } else {
+                bail!(Error::Config, "`region` required")
+            };
+            format!("https://{}.s3.{}.amazonaws.com/", bucket_name, region)
+        }
         EndPoint::DigitalOceanSpaces => {
-            format!("https://{}.{}.digitaloceanspaces.com/", bucket_name, region,)
+            let region = if let Some(region) = region {
+                region
+            } else {
+                bail!(Error::Config, "`region` required")
+            };
+            format!("https://{}.{}.digitaloceanspaces.com/", bucket_name, region)
         }
+        EndPoint::GCS => format!("https://storage.googleapis.com/{}/", bucket_name),
     };
 
+    let api_url = match end_point {
+        EndPoint::S3 | EndPoint::DigitalOceanSpaces => format!(
+            "{}?list-type=2&max-keys={}{}",
+            download_base_url, MAX_KEYS, prefix
+        ),
+        EndPoint::GCS => format!("{}?max-keys={}{}", download_base_url, MAX_KEYS, prefix),
+    };
+
+    debug!("using api url: {:?}", api_url);
+
     let resp = reqwest::blocking::Client::new().get(&api_url).send()?;
     if !resp.status().is_success() {
         bail!(

src/lib.rs

@@ -54,7 +54,7 @@ fn update() -> Result<(), Box<::std::error::Error>> {
 Run the above example to see `self_update` in action: `cargo run --example github --features "archive-tar compression-flate2"`.
 There's also an equivalent example for gitlab: `cargo run --example gitlab --features "archive-tar compression-flate2"`.
 
-Amazon S3 and DigitalOcean Spaces are also supported through the `S3` backend to check for new releases. Provided a `bucket_name`
+Amazon S3, Google GCS, and DigitalOcean Spaces are also supported through the `S3` backend to check for new releases. Provided a `bucket_name`
 and `asset_prefix` string, `self_update` will look up all matching files using the following format
 as a convention for the filenames: `[directory/]<asset name>-<semver>-<platform/target>.<extension>`.
 Leading directories will be stripped from the file name allowing the use of subdirectories in the S3 bucket,