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Sink readFile impl for GitSourceAccessor
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@b-camacho
b-camacho committed Nov 5, 2024
1 parent f4962fe commit d2d6f20
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Showing 2 changed files with 142 additions and 156 deletions.
269 changes: 117 additions & 152 deletions src/libfetchers/git-lfs-fetch.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -11,9 +11,13 @@
#include <stdexcept>
#include <string>

#include "serialise.hh"
#include "processes.hh"


namespace fs = std::filesystem;

namespace nix {
namespace lfs {

// see Fetch::rules
Expand Down Expand Up @@ -50,8 +54,8 @@ struct Fetch {

void init(git_repository* repo, std::string gitattributesContent);
bool hasAttribute(const std::string& path, const std::string& attrName) const;
std::string download(const std::string& data, const std::string& path) const;
std::vector<nlohmann::json> fetch_urls(const std::vector<Md> &metadatas) const;
void fetch(const std::string& pointerFileContents, const std::string& pointerFilePath, Sink& sink) const;
std::vector<nlohmann::json> fetchUrls(const std::vector<Md> &metadatas) const;
};

bool matchesPattern(std::string_view path, std::string_view pattern) {
Expand Down Expand Up @@ -84,7 +88,7 @@ bool matchesPattern(std::string_view path, std::string_view pattern) {
return patternPos == pattern.length() && pathPos == path.length();
}

static size_t WriteCallback(void *contents, size_t size, size_t nmemb,
static size_t writeCallback(void *contents, size_t size, size_t nmemb,
std::string *s) {
size_t newLength = size * nmemb;
try {
Expand All @@ -96,34 +100,62 @@ static size_t WriteCallback(void *contents, size_t size, size_t nmemb,
return newLength;
}

std::string download_to_memory(const std::string &url, const std::string &auth_header) {
CURL *curl;
CURLcode res;
std::string response_string;

curl = curl_easy_init();
if (curl) {
curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response_string);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

struct curl_slist *headers = nullptr;
const std::string auth_header_prepend = "Authorization: " + auth_header;
headers = curl_slist_append(headers, auth_header_prepend.c_str());
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

res = curl_easy_perform(curl);
if (res != CURLE_OK) {
std::cerr << "curl_easy_perform() failed: " << curl_easy_strerror(res)
<< std::endl;
struct SinkCallbackData {
Sink* sink;
std::string_view sha256Expected;
HashSink hashSink;

SinkCallbackData(Sink* sink, std::string_view sha256)
: sink(sink)
, sha256Expected(sha256)
, hashSink(HashAlgorithm::SHA256)
{}
};

static size_t sinkWriteCallback(void *contents, size_t size, size_t nmemb, SinkCallbackData *data) {
size_t totalSize = size * nmemb;
try {
data->hashSink({(char *)contents, totalSize});
(*data->sink)({(char *)contents, totalSize});
} catch (std::exception &e) {
return 0;
}
return totalSize;
}

curl_slist_free_all(headers);
curl_easy_cleanup(curl);
}
void downloadToSink(const std::string &url, const std::string &authHeader, Sink &sink, std::string_view sha256Expected) {
CURL *curl;
CURLcode res;

curl = curl_easy_init();
if (curl) {
SinkCallbackData data(&sink, sha256Expected);

curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, sinkWriteCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &data);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

struct curl_slist *headers = nullptr;
const std::string authHeader_prepend = "Authorization: " + authHeader;
headers = curl_slist_append(headers, authHeader_prepend.c_str());
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

res = curl_easy_perform(curl);
if (res != CURLE_OK) {
curl_slist_free_all(headers);
curl_easy_cleanup(curl);
throw std::runtime_error(std::string("curl_easy_perform() failed: ") + curl_easy_strerror(res));
}

const auto sha256Actual = data.hashSink.finish().first.to_string(HashFormat::Base16, false);
if (sha256Actual != data.sha256Expected) {
throw std::runtime_error("sha256 mismatch: while fetching " + url + ": expected " + std::string(data.sha256Expected) + " but got " + sha256Actual);
}

return response_string;
curl_slist_free_all(headers);
curl_easy_cleanup(curl);
}
}


Expand Down Expand Up @@ -207,32 +239,14 @@ std::vector<AttrRule> parseGitAttrFile(std::string_view content)



std::string exec_command(const std::string &cmd) {
std::cout << cmd << std::endl;
std::string data;
std::array<char, 256> buffer;
std::string result;
std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd.c_str(), "r"),
pclose);
if (!pipe) {
throw std::runtime_error("popen() failed!");
}
while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
result += buffer.data();
}
if (result.back() == '\n') {
result.pop_back();
}
return result;
}

std::string get_lfs_api_token(const std::string &host,
std::string getLfsApiToken(const std::string &host,
const std::string &path) {
std::string command =
"ssh git@" + host + " git-lfs-authenticate " + path + " download";
std::string output = exec_command(command);
std::string res;
auto [status, output] = runProgram(RunOptions {
.program = "ssh",
.args = {"git@" + host, "git-lfs-authenticate", path, "download"},
});

std::string res;
if (!output.empty()) {
nlohmann::json query_resp = nlohmann::json::parse(output);
res = query_resp["header"]["Authorization"].get<std::string>();
Expand All @@ -241,10 +255,10 @@ std::string get_lfs_api_token(const std::string &host,
return res;
}

std::string get_lfs_endpoint_url(git_repository *repo) {
std::string getLfsEndpointUrl(git_repository *repo) {
int err;
git_remote* remote = NULL;
err = git_remote_lookup(&remote, repo, "origin"); // TODO: we just created this repo so I think origin is always the only remote, but should double check
err = git_remote_lookup(&remote, repo, "origin");
if (err < 0) {
std::cerr << " failed git_remote_lookup with: " << err << std::endl;
return "";
Expand All @@ -261,7 +275,7 @@ std::string get_lfs_endpoint_url(git_repository *repo) {
}

// splits url into (hostname, path)
std::tuple<std::string, std::string> split_url(const std::string& url_in) {
std::tuple<std::string, std::string> splitUrl(const std::string& url_in) {
CURLU *url = curl_url();

if (curl_url_set(url, CURLUPART_URL, url_in.c_str(), 0) != CURLUE_OK) {
Expand Down Expand Up @@ -328,54 +342,11 @@ std::unique_ptr<std::vector<std::string>> find_lfs_files(git_repository *repo) {
return out;
}

std::string get_obj_content(git_repository *repo, std::string path) {
// Get the HEAD commit
git_object *obj = nullptr;
if (git_revparse_single(&obj, repo, "HEAD^{commit}") != 0) {
std::cerr << "Failed to find HEAD" << std::endl;
return "";
}

git_commit *commit = nullptr;
git_commit_lookup(&commit, repo, git_object_id(obj));
git_object_free(obj);

git_tree *tree = nullptr;
if (git_commit_tree(&tree, commit) != 0) {
std::cerr << "Failed to get tree from commit" << std::endl;
git_commit_free(commit);
return "";
}

git_tree_entry *entry;
if (git_tree_entry_bypath(&entry, tree, path.c_str()) != 0) {
std::cerr << "Failed to find " << path << " in the tree" << std::endl;
git_tree_free(tree);
git_commit_free(commit);
return "";
}

git_blob *blob = nullptr;
if (git_blob_lookup(&blob, repo, git_tree_entry_id(entry)) != 0) {
std::cerr << "Failed to lookup blob" << std::endl;
git_tree_entry_free(
const_cast<git_tree_entry *>(entry)); // Free entry after use
git_tree_free(tree);
git_commit_free(commit);
return "";
}

auto content = git_blob_rawcontent(blob);
git_object_free(obj);
git_tree_free(tree);
git_commit_free(commit);

// is this copy elided? i wont pretend to understand
// https://en.cppreference.com/w/cpp/language/copy_elision
return std::string(static_cast<const char *>(content));
}

Md parse_lfs_metadata(const std::string &content, const std::string &filename) {
Md parseLfsMetadata(const std::string &content, const std::string &filename) {
// example git-lfs poitner file:
// version https://git-lfs.github.com/spec/v1
// oid sha256:f5e02aa71e67f41d79023a128ca35bad86cf7b6656967bfe0884b3a3c4325eaf
// size 10000000
std::istringstream iss(content);
std::string line;
std::string oid;
Expand All @@ -384,14 +355,14 @@ Md parse_lfs_metadata(const std::string &content, const std::string &filename) {
while (getline(iss, line)) {
std::size_t pos = line.find("oid sha256:");
if (pos != std::string::npos) {
oid = line.substr(pos + 11); // Extract hash after "oid sha256:"
oid = line.substr(pos + 11); // skip "oid sha256:"
continue;
}

pos = line.find("size ");
if (pos != std::string::npos) {
std::string sizeStr =
line.substr(pos + 5); // Extract size number after "size "
line.substr(pos + 5); // skip "size "
size = std::stol(sizeStr);
continue;
}
Expand All @@ -401,9 +372,9 @@ Md parse_lfs_metadata(const std::string &content, const std::string &filename) {
}

void Fetch::init(git_repository* repo, std::string gitattributesContent) {
this->rootUrl = lfs::get_lfs_endpoint_url(repo);
const auto [host, path] = lfs::split_url(rootUrl);
this->token = lfs::get_lfs_api_token(host, path);
this->rootUrl = lfs::getLfsEndpointUrl(repo);
const auto [host, path] = lfs::splitUrl(rootUrl);
this->token = lfs::getLfsApiToken(host, path);
this->rules = lfs::parseGitAttrFile(gitattributesContent);
this->ready = true;
}
Expand All @@ -424,85 +395,79 @@ bool Fetch::hasAttribute(const std::string& path, const std::string& attrName) c
}

nlohmann::json mdToPayload(const std::vector<Md> &items) {
nlohmann::json j_array = nlohmann::json::array();
nlohmann::json jArray = nlohmann::json::array();
for (const auto &md : items) {
j_array.push_back({{"oid", md.oid}, {"size", md.size}});
jArray.push_back({{"oid", md.oid}, {"size", md.size}});
}
return j_array;
return jArray;
}

std::vector<nlohmann::json> Fetch::fetch_urls(const std::vector<Md> &metadatas) const {
std::vector<nlohmann::json> objects;

nlohmann::json oid_list = mdToPayload(metadatas);
std::vector<nlohmann::json> Fetch::fetchUrls(const std::vector<Md> &metadatas) const {
nlohmann::json oidList = mdToPayload(metadatas);
nlohmann::json data = {
{"operation", "download"},
};
data["objects"] = oid_list;
auto data_str = data.dump();
data["objects"] = oidList;
auto dataStr = data.dump();

CURL *curl = curl_easy_init();
std::string response_string;
std::string header_string;
auto lfs_url_batch = rootUrl + "/info/lfs/objects/batch";
curl_easy_setopt(curl, CURLOPT_URL, lfs_url_batch.c_str());
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data_str.c_str());
std::string responseString;
std::string headerString;
auto lfsUrlBatch = rootUrl + "/info/lfs/objects/batch";
curl_easy_setopt(curl, CURLOPT_URL, lfsUrlBatch.c_str());
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, dataStr.c_str());

// Set headers
struct curl_slist *headers = NULL;
auto auth_header = "Authorization: " + token;
headers = curl_slist_append(headers, auth_header.c_str());
auto authHeader = "Authorization: " + token;
headers = curl_slist_append(headers, authHeader.c_str());
headers =
curl_slist_append(headers, "Content-Type: application/vnd.git-lfs+json");
headers = curl_slist_append(headers, "Accept: application/vnd.git-lfs+json");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_POST, 1L);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response_string);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseString);

CURLcode res = curl_easy_perform(curl);
// Check for errors
if (res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));

curl_easy_cleanup(curl);
curl_slist_free_all(headers);

try {
// example resp here:
// {"objects":[{"oid":"f5e02aa71e67f41d79023a128ca35bad86cf7b6656967bfe0884b3a3c4325eaf","size":10000000,"actions":{"download":{"href":"https://gitlab.com/b-camacho/test-lfs.git/gitlab-lfs/objects/f5e02aa71e67f41d79023a128ca35bad86cf7b6656967bfe0884b3a3c4325eaf","header":{"Authorization":"Basic
// Yi1jYW1hY2hvOmV5SjBlWEFpT2lKS1YxUWlMQ0poYkdjaU9pSklVekkxTmlKOS5leUprWVhSaElqcDdJbUZqZEc5eUlqb2lZaTFqWVcxaFkyaHZJbjBzSW1wMGFTSTZJbUptTURZNFpXVTFMVEprWmpVdE5HWm1ZUzFpWWpRMExUSXpNVEV3WVRReU1qWmtaaUlzSW1saGRDSTZNVGN4TkRZeE16ZzBOU3dpYm1KbUlqb3hOekUwTmpFek9EUXdMQ0psZUhBaU9qRTNNVFEyTWpFd05EVjkuZk9yMDNkYjBWSTFXQzFZaTBKRmJUNnJTTHJPZlBwVW9lYllkT0NQZlJ4QQ=="}}},"authenticated":true}]}
auto resp = nlohmann::json::parse(response_string);
if (resp.contains("objects")) {
objects.insert(objects.end(), resp["objects"].begin(),
resp["objects"].end());
} else {
throw std::runtime_error("Response does not contain 'objects'");
}
} catch (std::exception &e) {
std::cerr << "Failed to parse JSON or invalid response: " << e.what()
<< std::endl;
std::vector<nlohmann::json> objects;
// example resp here:
// {"objects":[{"oid":"f5e02aa71e67f41d79023a128ca35bad86cf7b6656967bfe0884b3a3c4325eaf","size":10000000,"actions":{"download":{"href":"https://gitlab.com/b-camacho/test-lfs.git/gitlab-lfs/objects/f5e02aa71e67f41d79023a128ca35bad86cf7b6656967bfe0884b3a3c4325eaf","header":{"Authorization":"Basic
// Yi1jYW1hY2hvOmV5SjBlWEFpT2lKS1YxUWlMQ0poYkdjaU9pSklVekkxTmlKOS5leUprWVhSaElqcDdJbUZqZEc5eUlqb2lZaTFqWVcxaFkyaHZJbjBzSW1wMGFTSTZJbUptTURZNFpXVTFMVEprWmpVdE5HWm1ZUzFpWWpRMExUSXpNVEV3WVRReU1qWmtaaUlzSW1saGRDSTZNVGN4TkRZeE16ZzBOU3dpYm1KbUlqb3hOekUwTmpFek9EUXdMQ0psZUhBaU9qRTNNVFEyTWpFd05EVjkuZk9yMDNkYjBWSTFXQzFZaTBKRmJUNnJTTHJPZlBwVW9lYllkT0NQZlJ4QQ=="}}},"authenticated":true}]}
auto resp = nlohmann::json::parse(responseString);
if (resp.contains("objects")) {
objects.insert(objects.end(), resp["objects"].begin(),
resp["objects"].end());
} else {
throw std::runtime_error("Response does not contain 'objects'");
}

return objects;
}

std::string Fetch::download(const std::string& pointer_data, const std::string& path) const {
const auto md = parse_lfs_metadata(pointer_data, path);
std::vector<Md> v_mds;
v_mds.push_back(md);
const auto obj_urls = fetch_urls(v_mds);
void Fetch::fetch(const std::string& pointerFileContents, const std::string& pointerFilePath, Sink& sink) const {
const auto md = parseLfsMetadata(pointerFileContents, pointerFilePath);
std::vector<Md> vMds;
vMds.push_back(md);
const auto objUrls = fetchUrls(vMds);

const auto obj = obj_urls[0];
const auto obj = objUrls[0];
std::string oid = obj["oid"];
std::string ourl = obj["actions"]["download"]["href"];
std::string auth_header =
obj["actions"]["download"]["header"]["Authorization"];
const auto data = lfs::download_to_memory(ourl, auth_header);
return data;
std::string authHeader =
obj["actions"]["download"]["header"]["Authorization"];
// oid is also the sha256
downloadToSink(ourl, authHeader, sink, oid);
}



} // namespace lfs

} // namespace nix
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