From 8956ae19879e0367250002b94e399d8c771f37a1 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 15 Nov 2017 14:16:04 +0100
Subject: [PATCH] Add a "profile" option to S3BinaryCacheStore

This allows specifying the AWS configuration profile to use. E.g.

  nix copy --from s3://my-cache?profile=aws-dev-account /nix/store/cf3isrlqavvd5w7rpky1fa8j9lcnlggm-...
---
 src/libstore/download.cc              |  2 +-
 src/libstore/s3-binary-cache-store.cc | 15 ++++++++++++---
 src/libstore/s3.hh                    |  2 +-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index 70f9b1f5e..da31029b4 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -533,7 +533,7 @@ struct CurlDownloader : public Downloader
             // FIXME: do this on a worker thread
             sync2async<DownloadResult>(success, failure, [&]() -> DownloadResult {
 #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 6a0f19238..0079da1be 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -10,6 +10,8 @@
 #include "istringstream_nocopy.hh"
 
 #include <aws/core/Aws.h>
+#include <aws/core/auth/AWSCredentialsProvider.h>
+#include <aws/core/auth/AWSCredentialsProviderChain.h>
 #include <aws/core/client/ClientConfiguration.h>
 #include <aws/core/client/DefaultRetryStrategy.h>
 #include <aws/core/utils/logging/FormattedLogSystem.h>
@@ -77,9 +79,15 @@ static void initAWS()
     });
 }
 
-S3Helper::S3Helper(const string & region)
+S3Helper::S3Helper(const std::string & profile, const std::string & region)
     : config(makeConfig(region))
-    , client(make_ref<Aws::S3::S3Client>(*config, true, false))
+    , client(make_ref<Aws::S3::S3Client>(
+            profile == ""
+            ? std::dynamic_pointer_cast<Aws::Auth::AWSCredentialsProvider>(
+                std::make_shared<Aws::Auth::DefaultAWSCredentialsProviderChain>())
+            : std::dynamic_pointer_cast<Aws::Auth::AWSCredentialsProvider>(
+                std::make_shared<Aws::Auth::ProfileConfigFileAWSCredentialsProvider>(profile.c_str())),
+            *config, true, false))
 {
 }
 
@@ -148,6 +156,7 @@ S3Helper::DownloadResult S3Helper::getObject(
 
 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> narinfoCompression{this, "", "narinfo-compression", "compression method for .narinfo files"};
     const Setting<std::string> lsCompression{this, "", "ls-compression", "compression method for .ls files"};
@@ -163,7 +172,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         const Params & params, const std::string & bucketName)
         : S3BinaryCacheStore(params)
         , bucketName(bucketName)
-        , s3Helper(region)
+        , s3Helper(profile, region)
     {
         diskCache = getNarInfoDiskCache();
     }
diff --git a/src/libstore/s3.hh b/src/libstore/s3.hh
index 08a7fbf96..4f9964003 100644
--- a/src/libstore/s3.hh
+++ b/src/libstore/s3.hh
@@ -14,7 +14,7 @@ struct S3Helper
     ref<Aws::Client::ClientConfiguration> config;
     ref<Aws::S3::S3Client> client;
 
-    S3Helper(const std::string & region);
+    S3Helper(const std::string & profile, const std::string & region);
 
     ref<Aws::Client::ClientConfiguration> makeConfig(const std::string & region);