Files
lix/lix/libfetchers/github.cc
T
eldritch horrors 8bfd2d4bb1 libfetchers: asyncify downloadFile, downloadTarball
Change-Id: I6f6e5b61667efeda8c575ae1f3bd87ee75fb9f9e
2025-02-08 17:26:19 +00:00

513 lines
19 KiB
C++

#include "lix/libfetchers/attrs.hh"
#include "lix/libstore/filetransfer.hh"
#include "lix/libfetchers/cache.hh"
#include "lix/libstore/globals.hh"
#include "lix/libfetchers/builtin-fetchers.hh"
#include "lix/libstore/store-api.hh"
#include "lix/libutil/async.hh"
#include "lix/libutil/types.hh"
#include "lix/libutil/url-parts.hh"
#include "lix/libutil/git.hh"
#include "lix/libfetchers/fetchers.hh"
#include "lix/libfetchers/fetch-settings.hh"
#include <optional>
#include <nlohmann/json.hpp>
#include <fstream>
namespace nix::fetchers {
struct DownloadUrl
{
std::string url;
Headers headers;
};
// A github, gitlab, or sourcehut host
const static std::string hostRegexS = "[a-zA-Z0-9.-]*"; // FIXME: check
std::regex hostRegex(hostRegexS, std::regex::ECMAScript);
struct GitArchiveInputScheme : InputScheme
{
virtual std::string type() const = 0;
virtual std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const = 0;
std::optional<Input> inputFromURL(const ParsedURL & url, bool requireTree) const override
{
if (url.scheme != type()) return {};
auto path = tokenizeString<std::vector<std::string>>(url.path, "/");
std::optional<std::string> refOrRev;
auto size = path.size();
if (size == 3) {
refOrRev = path[2];
} else if (size > 3) {
std::string rs;
for (auto i = std::next(path.begin(), 2); i != path.end(); i++) {
rs += *i;
if (std::next(i) != path.end()) {
rs += "/";
}
}
if (std::regex_match(rs, refRegex)) {
refOrRev = rs;
} else {
throw BadURL("in URL '%s', '%s' is not a branch/tag name", url.url, rs);
}
} else if (size < 2)
throw BadURL("URL '%s' is invalid", url.url);
Attrs attrs;
attrs.emplace("type", type());
attrs.emplace("owner", path[0]);
attrs.emplace("repo", path[1]);
for (auto &[name, value] : url.query) {
if (name == "rev" || name == "ref") {
if (refOrRev) {
throw BadURL("URL '%s' already contains a ref or rev", url.url);
} else {
refOrRev = value;
}
} else if (name == "lastModified") {
if (auto n = string2Int<uint64_t>(value)) {
attrs.emplace(name, *n);
} else {
throw Error(
"Attribute 'lastModified' in URL '%s' must be an integer",
url.to_string()
);
}
} else {
attrs.emplace(name, value);
}
}
if (refOrRev) attrs.emplace("refOrRev", *refOrRev);
return inputFromAttrs(attrs);
}
std::optional<Input> inputFromAttrs(const Attrs & attrs) const override
{
// Attributes can contain refOrRev and it needs to be figured out
// which one it is (see inputFromURL for when that may happen).
// The correct one (ref or rev) will be written into finalAttrs and
// it needs to be mutable for that.
Attrs finalAttrs(attrs);
auto type_ = maybeGetStrAttr(finalAttrs, "type");
if (type_ != type()) return {};
auto owner = getStrAttr(finalAttrs, "owner");
auto repo = getStrAttr(finalAttrs, "repo");
auto url = fmt("%s:%s/%s", *type_, owner, repo);
if (auto host = maybeGetStrAttr(finalAttrs, "host")) {
if (!std::regex_match(*host, hostRegex)) {
throw BadURL("URL '%s' contains an invalid instance host", url);
}
}
if (auto refOrRev = maybeGetStrAttr(finalAttrs, "refOrRev")) {
finalAttrs.erase("refOrRev");
if (std::regex_match(*refOrRev, revRegex)) {
finalAttrs.emplace("rev", *refOrRev);
} else if (std::regex_match(*refOrRev, refRegex)) {
finalAttrs.emplace("ref", *refOrRev);
} else {
throw Error(
"in URL '%s', '%s' is not a commit hash or a branch/tag name",
url,
*refOrRev
);
}
} else if (auto ref = maybeGetStrAttr(finalAttrs, "ref")) {
if (!std::regex_match(*ref, refRegex)) {
throw BadURL("URL '%s' contains an invalid branch/tag name", url);
}
}
for (auto & [name, value] : finalAttrs) {
if (name != "type" && name != "owner" && name != "repo" && name != "ref" && name != "rev" && name != "narHash" && name != "lastModified" && name != "host") {
throw Error("unsupported input attribute '%s'", name);
}
}
Input input;
input.attrs = finalAttrs;
return input;
}
ParsedURL toURL(const Input & input) const override
{
auto owner = getStrAttr(input.attrs, "owner");
auto repo = getStrAttr(input.attrs, "repo");
auto ref = input.getRef();
auto rev = input.getRev();
auto path = owner + "/" + repo;
assert(!(ref && rev));
if (ref) path += "/" + *ref;
if (rev) path += "/" + rev->to_string(Base::Base16, false);
return ParsedURL {
.scheme = type(),
.path = path,
};
}
bool hasAllInfo(const Input & input) const override
{
return input.getRev() && maybeGetIntAttr(input.attrs, "lastModified");
}
Input applyOverrides(
const Input & _input,
std::optional<std::string> ref,
std::optional<Hash> rev) const override
{
auto input(_input);
if (rev && ref)
throw BadURL("cannot apply both a commit hash (%s) and a branch/tag name ('%s') to input '%s'",
rev->gitRev(), *ref, input.to_string());
if (rev) {
input.attrs.insert_or_assign("rev", rev->gitRev());
input.attrs.erase("ref");
}
if (ref) {
input.attrs.insert_or_assign("ref", *ref);
input.attrs.erase("rev");
}
return input;
}
std::optional<std::string> getAccessToken(const std::string & host) const
{
auto tokens = fetchSettings.accessTokens.get();
if (auto token = get(tokens, host))
return *token;
return {};
}
Headers makeHeadersWithAuthTokens(const std::string & host) const
{
Headers headers;
auto accessToken = getAccessToken(host);
if (accessToken) {
auto hdr = accessHeaderFromToken(*accessToken);
if (hdr)
headers.push_back(*hdr);
else
warn("Unrecognized access token for host '%s'", host);
}
return headers;
}
virtual kj::Promise<Result<Hash>>
getRevFromRef(nix::ref<Store> store, const Input & input) const = 0;
virtual DownloadUrl getDownloadUrl(const Input & input) const = 0;
kj::Promise<Result<std::pair<StorePath, Input>>>
fetch(ref<Store> store, const Input & _input) override
try {
Input input(_input);
if (!maybeGetStrAttr(input.attrs, "ref")) input.attrs.insert_or_assign("ref", "HEAD");
auto rev = input.getRev();
if (!rev) rev = TRY_AWAIT(getRevFromRef(store, input));
input.attrs.erase("ref");
input.attrs.insert_or_assign("rev", rev->gitRev());
auto url = getDownloadUrl(input);
auto result =
TRY_AWAIT(downloadTarball(store, url.url, input.getName(), true, url.headers));
input.attrs.insert_or_assign("lastModified", uint64_t(result.lastModified));
co_return {result.tree.storePath, input};
} catch (...) {
co_return result::current_exception();
}
};
struct GitHubInputScheme : GitArchiveInputScheme
{
std::string type() const override { return "github"; }
std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const override
{
// Github supports PAT/OAuth2 tokens and HTTP Basic
// Authentication. The former simply specifies the token, the
// latter can use the token as the password. Only the first
// is used here. See
// https://developer.github.com/v3/#authentication and
// https://docs.github.com/en/developers/apps/authorizing-oath-apps
return std::pair<std::string, std::string>("Authorization", fmt("token %s", token));
}
std::string getHost(const Input & input) const
{
return maybeGetStrAttr(input.attrs, "host").value_or("github.com");
}
std::string getOwner(const Input & input) const
{
return getStrAttr(input.attrs, "owner");
}
std::string getRepo(const Input & input) const
{
return getStrAttr(input.attrs, "repo");
}
kj::Promise<Result<Hash>>
getRevFromRef(nix::ref<Store> store, const Input & input) const override
try {
auto host = getHost(input);
auto url = fmt(
host == "github.com"
? "https://api.%s/repos/%s/%s/commits/%s"
: "https://%s/api/v3/repos/%s/%s/commits/%s",
host, getOwner(input), getRepo(input), *input.getRef());
Headers headers = makeHeadersWithAuthTokens(host);
auto json = nlohmann::json::parse(readFile(store->toRealPath(
TRY_AWAIT(downloadFile(store, url, "source", false, headers)).storePath
)));
auto rev = Hash::parseAny(std::string { json["sha"] }, HashType::SHA1);
debug("HEAD revision for '%s' is %s", url, rev.gitRev());
co_return rev;
} catch (...) {
co_return result::current_exception();
}
DownloadUrl getDownloadUrl(const Input & input) const override
{
auto host = getHost(input);
Headers headers = makeHeadersWithAuthTokens(host);
// If we have no auth headers then we default to the public archive
// urls so we do not run into rate limits.
const auto urlFmt =
host != "github.com"
? "https://%s/api/v3/repos/%s/%s/tarball/%s"
: !getAccessToken(host)
? "https://%s/%s/%s/archive/%s.tar.gz"
: "https://api.%s/repos/%s/%s/tarball/%s";
const auto url = fmt(urlFmt, host, getOwner(input), getRepo(input),
input.getRev()->to_string(Base::Base16, false));
return DownloadUrl { url, headers };
}
void clone(const Input & input, const Path & destDir) const override
{
auto host = getHost(input);
Input::fromURL(fmt("git+https://%s/%s/%s.git",
host, getOwner(input), getRepo(input)))
.applyOverrides(input.getRef(), input.getRev())
.clone(destDir);
}
Headers makeHeadersWithAuthTokens(const std::string & host) const
{
Headers headers = GitArchiveInputScheme::makeHeadersWithAuthTokens(host);
headers.emplace_back("X-GitHub-Api-Version", "2022-11-28");
return headers;
}
};
struct GitLabInputScheme : GitArchiveInputScheme
{
std::string type() const override { return "gitlab"; }
std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const override
{
// Gitlab supports 4 kinds of authorization, two of which are
// relevant here: OAuth2 and PAT (Private Access Token). The
// user can indicate which token is used by specifying the
// token as <TYPE>:<VALUE>, where type is "OAuth2" or "PAT".
// If the <TYPE> is unrecognized, this will fall back to
// treating this simply has <HDRNAME>:<HDRVAL>. See
// https://docs.gitlab.com/12.10/ee/api/README.html#authentication
auto fldsplit = token.find_first_of(':');
// n.b. C++20 would allow: if (token.starts_with("OAuth2:")) ...
if ("OAuth2" == token.substr(0, fldsplit))
return std::make_pair("Authorization", fmt("Bearer %s", token.substr(fldsplit+1)));
if ("PAT" == token.substr(0, fldsplit))
return std::make_pair("Private-token", token.substr(fldsplit+1));
warn("Unrecognized GitLab token type %s", token.substr(0, fldsplit));
return std::make_pair(token.substr(0,fldsplit), token.substr(fldsplit+1));
}
kj::Promise<Result<Hash>>
getRevFromRef(nix::ref<Store> store, const Input & input) const override
try {
auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
// See rate limiting note below
auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/commits?ref_name=%s",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
Headers headers = makeHeadersWithAuthTokens(host);
auto json = nlohmann::json::parse(readFile(store->toRealPath(
TRY_AWAIT(downloadFile(store, url, "source", false, headers)).storePath
)));
if (json.is_array() && json.size() >= 1 && json[0]["id"] != nullptr) {
auto rev = Hash::parseAny(std::string(json[0]["id"]), HashType::SHA1);
debug("HEAD revision for '%s' is %s", url, rev.gitRev());
co_return rev;
} else if (json.is_array() && json.size() == 0) {
throw Error("No commits returned by GitLab API -- does the ref really exist?");
} else {
throw Error("Didn't know what to do with response from GitLab: %s", json);
}
} catch (...) {
co_return result::current_exception();
}
DownloadUrl getDownloadUrl(const Input & input) const override
{
// This endpoint has a rate limit threshold that may be
// server-specific and vary based whether the user is
// authenticated via an accessToken or not, but the usual rate
// is 10 reqs/sec/ip-addr. See
// https://docs.gitlab.com/ee/user/gitlab_com/index.html#gitlabcom-specific-rate-limits
auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/archive.tar.gz?sha=%s",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
input.getRev()->to_string(Base::Base16, false));
Headers headers = makeHeadersWithAuthTokens(host);
return DownloadUrl { url, headers };
}
void clone(const Input & input, const Path & destDir) const override
{
auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
// FIXME: get username somewhere
Input::fromURL(fmt("git+https://%s/%s/%s.git",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
.applyOverrides(input.getRef(), input.getRev())
.clone(destDir);
}
};
struct SourceHutInputScheme : GitArchiveInputScheme
{
std::string type() const override { return "sourcehut"; }
std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const override
{
// SourceHut supports both PAT and OAuth2. See
// https://man.sr.ht/meta.sr.ht/oauth.md
return std::pair<std::string, std::string>("Authorization", fmt("Bearer %s", token));
// Note: This currently serves no purpose, as this kind of authorization
// does not allow for downloading tarballs on sourcehut private repos.
// Once it is implemented, however, should work as expected.
}
kj::Promise<Result<Hash>>
getRevFromRef(nix::ref<Store> store, const Input & input) const override
try {
// TODO: In the future, when the sourcehut graphql API is implemented for mercurial
// and with anonymous access, this method should use it instead.
auto ref = *input.getRef();
auto host = maybeGetStrAttr(input.attrs, "host").value_or("git.sr.ht");
auto base_url = fmt("https://%s/%s/%s",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"));
Headers headers = makeHeadersWithAuthTokens(host);
std::string refUri;
if (ref == "HEAD") {
auto file = store->toRealPath(
TRY_AWAIT(downloadFile(store, fmt("%s/HEAD", base_url), "source", false, headers))
.storePath
);
std::ifstream is(file);
std::string line;
getline(is, line);
auto remoteLine = git::parseLsRemoteLine(line);
if (!remoteLine) {
throw BadURL("in '%d', couldn't resolve HEAD ref '%d'", input.to_string(), ref);
}
refUri = remoteLine->target;
} else {
refUri = fmt("refs/(heads|tags)/%s", ref);
}
std::regex refRegex(refUri);
auto file = store->toRealPath(
TRY_AWAIT(downloadFile(store, fmt("%s/info/refs", base_url), "source", false, headers))
.storePath
);
std::ifstream is(file);
std::string line;
std::optional<std::string> id;
while(!id && getline(is, line)) {
auto parsedLine = git::parseLsRemoteLine(line);
if (parsedLine && parsedLine->reference && std::regex_match(*parsedLine->reference, refRegex))
id = parsedLine->target;
}
if(!id)
throw BadURL("in '%d', couldn't find ref '%d'", input.to_string(), ref);
auto rev = Hash::parseAny(*id, HashType::SHA1);
debug("HEAD revision for '%s' is %s", fmt("%s/%s", base_url, ref), rev.gitRev());
co_return rev;
} catch (...) {
co_return result::current_exception();
}
DownloadUrl getDownloadUrl(const Input & input) const override
{
auto host = maybeGetStrAttr(input.attrs, "host").value_or("git.sr.ht");
auto url = fmt("https://%s/%s/%s/archive/%s.tar.gz",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
input.getRev()->to_string(Base::Base16, false));
Headers headers = makeHeadersWithAuthTokens(host);
return DownloadUrl { url, headers };
}
void clone(const Input & input, const Path & destDir) const override
{
auto host = maybeGetStrAttr(input.attrs, "host").value_or("git.sr.ht");
Input::fromURL(fmt("git+https://%s/%s/%s",
host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
.applyOverrides(input.getRef(), input.getRev())
.clone(destDir);
}
};
std::unique_ptr<InputScheme> makeGitHubInputScheme()
{
return std::make_unique<GitHubInputScheme>();
}
std::unique_ptr<InputScheme> makeGitLabInputScheme()
{
return std::make_unique<GitLabInputScheme>();
}
std::unique_ptr<InputScheme> makeSourceHutInputScheme()
{
return std::make_unique<SourceHutInputScheme>();
}
}