Implement S3BinaryCacheStore::queryAllValidPaths()

This allows commands like "nix verify --all" or "nix path-info --all"
to work on S3 caches.

Unfortunately, this requires some ugly hackery: when querying the
contents of the bucket, we don't want to have to read every .narinfo
file. But the S3 bucket keys only include the hash part of each store
path, not the name part. So as a special exception
queryAllValidPaths() can now return store paths *without* the name
part, and queryPathInfo() accepts such store paths (returning a
ValidPathInfo object containing the full name).

1 files changed, 34 insertions, 1 deletions

diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 9ac79cf416de..6fadf7be28c9 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -10,6 +10,7 @@
 #include <aws/s3/model/GetObjectRequest.h>
 #include <aws/s3/model/HeadObjectRequest.h>
 #include <aws/s3/model/PutObjectRequest.h>
+#include <aws/s3/model/ListObjectsRequest.h>
 
 namespace nix {
 
@@ -164,7 +165,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
 
     std::shared_ptr<std::string> getFile(const std::string & path)
     {
-        printMsg(lvlDebug, format("fetching ‘s3://%1%/%2%’...") % bucketName % path);
+        debug(format("fetching ‘s3://%1%/%2%’...") % bucketName % path);
 
         auto request =
             Aws::S3::Model::GetObjectRequest()
@@ -204,6 +205,38 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         }
     }
 
+    PathSet queryAllValidPaths() override
+    {
+        PathSet paths;
+        std::string marker;
+
+        do {
+            debug(format("listing bucket ‘s3://%s’ from key ‘%s’...") % bucketName % marker);
+
+            auto res = checkAws(format("AWS error listing bucket ‘%s’") % bucketName,
+                client->ListObjects(
+                    Aws::S3::Model::ListObjectsRequest()
+                    .WithBucket(bucketName)
+                    .WithDelimiter("/")
+                    .WithMarker(marker)));
+
+            auto & contents = res.GetContents();
+
+            debug(format("got %d keys, next marker ‘%s’")
+                % contents.size() % res.GetNextMarker());
+
+            for (auto object : contents) {
+                auto & key = object.GetKey();
+                if (!hasSuffix(key, ".narinfo")) continue;
+                paths.insert(settings.nixStore + "/" + std::string(key, 0, key.size() - 8));
+            }
+
+            marker = res.GetNextMarker();
+        } while (!marker.empty());
+
+        return paths;
+    }
+
 };
 
 static RegisterStoreImplementation regStore([](const std::string & uri) -> std::shared_ptr<Store> {