refactor(libstore): expose HttpBinaryCacheStore and add S3BinaryCacheStore

Move HttpBinaryCacheStore class from .cc file to header to enable
inheritance by S3BinaryCacheStore. Create S3BinaryCacheStore class that
overrides upsertFile() to implement multipart upload logic.

src/libstore/http-binary-cache-store.cc

@@ -51,32 +51,16 @@ std::string HttpBinaryCacheStoreConfig::doc()
         ;
 }
 
-class HttpBinaryCacheStore : public virtual BinaryCacheStore
+HttpBinaryCacheStore::HttpBinaryCacheStore(ref<Config> config)
-{
-    struct State
-    {
-        bool enabled = true;
-        std::chrono::steady_clock::time_point disabledUntil;
-    };
-
-    Sync<State> _state;
-
-public:
-
-    using Config = HttpBinaryCacheStoreConfig;
-
-    ref<Config> config;
-
-    HttpBinaryCacheStore(ref<Config> config)
     : Store{*config} // TODO it will actually mutate the configuration
     , BinaryCacheStore{*config}
     , config{config}
-    {
+{
     diskCache = getNarInfoDiskCache();
-    }
+}
 
-    void init() override
+void HttpBinaryCacheStore::init()
-    {
+{
     // FIXME: do this lazily?
     // For consistent cache key handling, use the reference without parameters
     // This matches what's used in Store::queryPathInfo() lookups
@@ -93,12 +77,10 @@ public:
         }
         diskCache->createCache(cacheKey, config->storeDir, config->wantMassQuery, config->priority);
     }
-    }
+}
 
-protected:
+std::optional<std::string> HttpBinaryCacheStore::getCompressionMethod(const std::string & path)
-
+{
-    std::optional<std::string> getCompressionMethod(const std::string & path)
-    {
     if (hasSuffix(path, ".narinfo") && !config->narinfoCompression.get().empty())
         return config->narinfoCompression;
     else if (hasSuffix(path, ".ls") && !config->lsCompression.get().empty())
@@ -107,10 +89,10 @@ protected:
         return config->logCompression;
     else
         return std::nullopt;
-    }
+}
 
-    void maybeDisable()
+void HttpBinaryCacheStore::maybeDisable()
-    {
+{
     auto state(_state.lock());
     if (state->enabled && settings.tryFallback) {
         int t = 60;
@@ -118,10 +100,10 @@ protected:
         state->enabled = false;
         state->disabledUntil = std::chrono::steady_clock::now() + std::chrono::seconds(t);
     }
-    }
+}
 
-    void checkEnabled()
+void HttpBinaryCacheStore::checkEnabled()
-    {
+{
     auto state(_state.lock());
     if (state->enabled)
         return;
@@ -131,10 +113,10 @@ protected:
         return;
     }
     throw SubstituterDisabled("substituter '%s' is disabled", config->getHumanReadableURI());
-    }
+}
 
-    bool fileExists(const std::string & path) override
+bool HttpBinaryCacheStore::fileExists(const std::string & path)
-    {
+{
     checkEnabled();
 
     try {
@@ -150,19 +132,21 @@ protected:
         maybeDisable();
         throw;
     }
-    }
+}
 
-    void upsertFile(
+void HttpBinaryCacheStore::upsertFile(
     const std::string & path,
     std::shared_ptr<std::basic_iostream<char>> istream,
     const std::string & mimeType,
-        uint64_t sizeHint) override
+    uint64_t sizeHint)
-    {
+{
     auto req = makeRequest(path);
 
     auto data = StreamToSourceAdapter(istream).drain();
 
-        if (auto compressionMethod = getCompressionMethod(path)) {
+    auto compressionMethod = getCompressionMethod(path);
+
+    if (compressionMethod) {
         data = compress(*compressionMethod, data);
         req.headers.emplace_back("Content-Encoding", *compressionMethod);
     }
@@ -173,13 +157,12 @@ protected:
     try {
         getFileTransfer()->upload(req);
     } catch (FileTransferError & e) {
-            throw UploadToHTTP(
+        throw UploadToHTTP("while uploading to HTTP binary cache at '%s': %s", config->cacheUri.to_string(), e.msg());
-                "while uploading to HTTP binary cache at '%s': %s", config->cacheUri.to_string(), e.msg());
-        }
     }
+}
 
-    FileTransferRequest makeRequest(const std::string & path)
+FileTransferRequest HttpBinaryCacheStore::makeRequest(const std::string & path)
-    {
+{
     /* Otherwise the last path fragment will get discarded. */
     auto cacheUriWithTrailingSlash = config->cacheUri;
     if (!cacheUriWithTrailingSlash.path.empty())
@@ -200,10 +183,10 @@ protected:
     }
 
     return FileTransferRequest(result);
-    }
+}
 
-    void getFile(const std::string & path, Sink & sink) override
+void HttpBinaryCacheStore::getFile(const std::string & path, Sink & sink)
-    {
+{
     checkEnabled();
     auto request(makeRequest(path));
     try {
@@ -215,10 +198,10 @@ protected:
         maybeDisable();
         throw;
     }
-    }
+}
 
-    void getFile(const std::string & path, Callback<std::optional<std::string>> callback) noexcept override
+void HttpBinaryCacheStore::getFile(const std::string & path, Callback<std::optional<std::string>> callback) noexcept
-    {
+{
     auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
 
     try {
@@ -226,12 +209,12 @@ protected:
 
         auto request(makeRequest(path));
 
-            getFileTransfer()->enqueueFileTransfer(
+        getFileTransfer()->enqueueFileTransfer(request, {[callbackPtr, this](std::future<FileTransferResult> result) {
-                request, {[callbackPtr, this](std::future<FileTransferResult> result) {
                                                    try {
                                                        (*callbackPtr)(std::move(result.get().data));
                                                    } catch (FileTransferError & e) {
-                        if (e.error == FileTransfer::NotFound || e.error == FileTransfer::Forbidden)
+                                                       if (e.error == FileTransfer::NotFound
+                                                           || e.error == FileTransfer::Forbidden)
                                                            return (*callbackPtr)({});
                                                        maybeDisable();
                                                        callbackPtr->rethrow();
@@ -244,10 +227,10 @@ protected:
         callbackPtr->rethrow();
         return;
     }
-    }
+}
 
-    std::optional<std::string> getNixCacheInfo() override
+std::optional<std::string> HttpBinaryCacheStore::getNixCacheInfo()
-    {
+{
     try {
         auto result = getFileTransfer()->download(makeRequest(cacheInfoFile));
         return result.data;
@@ -257,9 +240,9 @@ protected:
         maybeDisable();
         throw;
     }
-    }
+}
 
-    /**
+/**
  * This isn't actually necessary read only. We support "upsert" now, so we
  * have a notion of authentication via HTTP POST/PUT.
  *
@@ -267,11 +250,10 @@ protected:
  *
  * \todo try to expose our HTTP authentication status.
  */
-    std::optional<TrustedFlag> isTrustedClient() override
+std::optional<TrustedFlag> HttpBinaryCacheStore::isTrustedClient()
-    {
+{
     return std::nullopt;
-    }
+}
-};
 
 ref<Store> HttpBinaryCacheStore::Config::openStore() const
 {

src/libstore/include/nix/store/http-binary-cache-store.hh

@@ -3,6 +3,10 @@
 
 #include "nix/util/url.hh"
 #include "nix/store/binary-cache-store.hh"
+#include "nix/store/filetransfer.hh"
+#include "nix/util/sync.hh"
+
+#include <chrono>
 
 namespace nix {
 
@@ -46,4 +50,51 @@ struct HttpBinaryCacheStoreConfig : std::enable_shared_from_this<HttpBinaryCache
     StoreReference getReference() const override;
 };
 
+class HttpBinaryCacheStore : public virtual BinaryCacheStore
+{
+    struct State
+    {
+        bool enabled = true;
+        std::chrono::steady_clock::time_point disabledUntil;
+    };
+
+    Sync<State> _state;
+
+public:
+
+    using Config = HttpBinaryCacheStoreConfig;
+
+    ref<Config> config;
+
+    HttpBinaryCacheStore(ref<Config> config);
+
+    void init() override;
+
+protected:
+
+    std::optional<std::string> getCompressionMethod(const std::string & path);
+
+    void maybeDisable();
+
+    void checkEnabled();
+
+    bool fileExists(const std::string & path) override;
+
+    void upsertFile(
+        const std::string & path,
+        std::shared_ptr<std::basic_iostream<char>> istream,
+        const std::string & mimeType,
+        uint64_t sizeHint) override;
+
+    FileTransferRequest makeRequest(const std::string & path);
+
+    void getFile(const std::string & path, Sink & sink) override;
+
+    void getFile(const std::string & path, Callback<std::optional<std::string>> callback) noexcept override;
+
+    std::optional<std::string> getNixCacheInfo() override;
+
+    std::optional<TrustedFlag> isTrustedClient() override;
+};
+
 } // namespace nix

src/libstore/include/nix/store/s3-binary-cache-store.hh

@@ -77,6 +77,8 @@ struct S3BinaryCacheStoreConfig : HttpBinaryCacheStoreConfig
     static std::string doc();
 
     std::string getHumanReadableURI() const override;
+
+    ref<Store> openStore() const override;
 };
 
 } // namespace nix

src/libstore/s3-binary-cache-store.cc

@@ -7,6 +7,36 @@
 
 namespace nix {
 
+class S3BinaryCacheStore : public virtual HttpBinaryCacheStore
+{
+public:
+    S3BinaryCacheStore(ref<S3BinaryCacheStoreConfig> config)
+        : Store{*config}
+        , BinaryCacheStore{*config}
+        , HttpBinaryCacheStore{config}
+        , s3Config{config}
+    {
+    }
+
+    void upsertFile(
+        const std::string & path,
+        std::shared_ptr<std::basic_iostream<char>> istream,
+        const std::string & mimeType,
+        uint64_t sizeHint) override;
+
+private:
+    ref<S3BinaryCacheStoreConfig> s3Config;
+};
+
+void S3BinaryCacheStore::upsertFile(
+    const std::string & path,
+    std::shared_ptr<std::basic_iostream<char>> istream,
+    const std::string & mimeType,
+    uint64_t sizeHint)
+{
+    HttpBinaryCacheStore::upsertFile(path, istream, mimeType, sizeHint);
+}
+
 StringSet S3BinaryCacheStoreConfig::uriSchemes()
 {
     return {"s3"};
@@ -51,6 +81,13 @@ std::string S3BinaryCacheStoreConfig::doc()
     )";
 }
 
+ref<Store> S3BinaryCacheStoreConfig::openStore() const
+{
+    auto sharedThis = std::const_pointer_cast<S3BinaryCacheStoreConfig>(
+        std::static_pointer_cast<const S3BinaryCacheStoreConfig>(shared_from_this()));
+    return make_ref<S3BinaryCacheStore>(ref{sharedThis});
+}
+
 static RegisterStoreImplementation<S3BinaryCacheStoreConfig> registerS3BinaryCacheStore;
 
 } // namespace nix