s3 binary cache: support specifying an endpoint

Works for uploading and not downloading.

4 files changed, 16 insertions, 8 deletions

diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index ecec0f205..f80c9e45b 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -598,7 +598,7 @@ struct CurlDownloader : public Downloader
             // FIXME: do this on a worker thread
             try {
 #ifdef ENABLE_S3
-                S3Helper s3Helper("", Aws::Region::US_EAST_1); // FIXME: make configurable
+                S3Helper s3Helper("", Aws::Region::US_EAST_1, ""); // FIXME: make configurable
                 auto slash = request.uri.find('/', 5);
                 if (slash == std::string::npos)
                     throw nix::Error("bad S3 URI '%s'", request.uri);
diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 26144ccb4..2f18e3f38 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -84,8 +84,8 @@ static void initAWS()
     });
 }
 
-S3Helper::S3Helper(const std::string & profile, const std::string & region)
-    : config(makeConfig(region))
+S3Helper::S3Helper(const std::string & profile, const std::string & region, const std::string & endpoint)
+    : config(makeConfig(region, endpoint))
     , client(make_ref<Aws::S3::S3Client>(
             profile == ""
             ? std::dynamic_pointer_cast<Aws::Auth::AWSCredentialsProvider>(
@@ -99,7 +99,7 @@ S3Helper::S3Helper(const std::string & profile, const std::string & region)
 #else
             Aws::Client::AWSAuthV4Signer::PayloadSigningPolicy::Never,
 #endif
-            false))
+            endpoint.empty()))
 {
 }
 
@@ -116,11 +116,14 @@ class RetryStrategy : public Aws::Client::DefaultRetryStrategy
     }
 };
 
-ref<Aws::Client::ClientConfiguration> S3Helper::makeConfig(const string & region)
+ref<Aws::Client::ClientConfiguration> S3Helper::makeConfig(const string & region, const string & endpoint)
 {
     initAWS();
     auto res = make_ref<Aws::Client::ClientConfiguration>();
     res->region = region;
+    if (!endpoint.empty()) {
+        res->endpointOverride = endpoint;
+    }
     res->requestTimeoutMs = 600 * 1000;
     res->retryStrategy = std::make_shared<RetryStrategy>();
     res->caFile = settings.caFile;
@@ -170,6 +173,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
 {
     const Setting<std::string> profile{this, "", "profile", "The name of the AWS configuration profile to use."};
     const Setting<std::string> region{this, Aws::Region::US_EAST_1, "region", {"aws-region"}};
+    const Setting<std::string> endpoint{this, "", "endpoint", "An optional override of the endpoint to use when talking to S3."};
     const Setting<std::string> narinfoCompression{this, "", "narinfo-compression", "compression method for .narinfo files"};
     const Setting<std::string> lsCompression{this, "", "ls-compression", "compression method for .ls files"};
     const Setting<std::string> logCompression{this, "", "log-compression", "compression method for log/* files"};
@@ -186,7 +190,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         const Params & params, const std::string & bucketName)
         : S3BinaryCacheStore(params)
         , bucketName(bucketName)
-        , s3Helper(profile, region)
+        , s3Helper(profile, region, endpoint)
     {
         diskCache = getNarInfoDiskCache();
     }
diff --git a/src/libstore/s3.hh b/src/libstore/s3.hh
index 4f9964003..95d612b66 100644
--- a/src/libstore/s3.hh
+++ b/src/libstore/s3.hh
@@ -14,9 +14,9 @@ struct S3Helper
     ref<Aws::Client::ClientConfiguration> config;
     ref<Aws::S3::S3Client> client;
 
-    S3Helper(const std::string & profile, const std::string & region);
+    S3Helper(const std::string & profile, const std::string & region, const std::string & endpoint);
 
-    ref<Aws::Client::ClientConfiguration> makeConfig(const std::string & region);
+    ref<Aws::Client::ClientConfiguration> makeConfig(const std::string & region, const std::string & endpoint);
 
     struct DownloadResult
     {
diff --git a/src/nix/copy.cc b/src/nix/copy.cc
index e4e6c3e30..91711c8b4 100644
--- a/src/nix/copy.cc
+++ b/src/nix/copy.cc
@@ -72,6 +72,10 @@ struct CmdCopy : StorePathsCommand
                 "To populate the current folder build output to a S3 binary cache:",
                 "nix copy --to s3://my-bucket?region=eu-west-1"
             },
+            Example{
+                "To populate the current folder build output to an S3-compatible binary cache:",
+                "nix copy --to s3://my-bucket?region=eu-west-1&endpoint=example.com"
+            },
 #endif
         };
     }