lix/src/libexpr/primops/flake.cc
2019-05-28 13:08:40 +02:00

607 lines
23 KiB
C++

#include "flake.hh"
#include "primops.hh"
#include "eval-inline.hh"
#include "fetchGit.hh"
#include "download.hh"
#include "args.hh"
#include <iostream>
#include <queue>
#include <regex>
#include <nlohmann/json.hpp>
namespace nix {
/* Read a registry. */
std::shared_ptr<FlakeRegistry> readRegistry(const Path & path)
{
auto registry = std::make_shared<FlakeRegistry>();
if (!pathExists(path))
return std::make_shared<FlakeRegistry>();
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
if (version != 1)
throw Error("flake registry '%s' has unsupported version %d", path, version);
auto flakes = json["flakes"];
for (auto i = flakes.begin(); i != flakes.end(); ++i)
registry->entries.emplace(i.key(), FlakeRef(i->value("uri", "")));
return registry;
}
/* Write a registry to a file. */
void writeRegistry(const FlakeRegistry & registry, const Path & path)
{
nlohmann::json json;
json["version"] = 1;
for (auto elem : registry.entries)
json["flakes"][elem.first.to_string()] = { {"uri", elem.second.to_string()} };
createDirs(dirOf(path));
writeFile(path, json.dump(4)); // The '4' is the number of spaces used in the indentation in the json file.
}
LockFile::FlakeEntry readFlakeEntry(nlohmann::json json)
{
FlakeRef flakeRef(json["uri"]);
if (!flakeRef.isImmutable())
throw Error("cannot use mutable flake '%s' in pure mode", flakeRef);
LockFile::FlakeEntry entry(flakeRef, Hash((std::string) json["contentHash"]));
auto nonFlakeRequires = json["nonFlakeRequires"];
for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
FlakeRef flakeRef(i->value("uri", ""));
if (!flakeRef.isImmutable())
throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef);
LockFile::NonFlakeEntry nonEntry(flakeRef, Hash(i->value("contentHash", "")));
entry.nonFlakeEntries.insert_or_assign(i.key(), nonEntry);
}
auto requires = json["requires"];
for (auto i = requires.begin(); i != requires.end(); ++i)
entry.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
return entry;
}
LockFile readLockFile(const Path & path)
{
LockFile lockFile;
if (!pathExists(path))
return lockFile;
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
if (version != 1)
throw Error("lock file '%s' has unsupported version %d", path, version);
auto nonFlakeRequires = json["nonFlakeRequires"];
for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
FlakeRef flakeRef(i->value("uri", ""));
LockFile::NonFlakeEntry nonEntry(flakeRef, Hash(i->value("contentHash", "")));
if (!flakeRef.isImmutable())
throw Error("found mutable FlakeRef '%s' in lockfile at path %s", flakeRef, path);
lockFile.nonFlakeEntries.insert_or_assign(i.key(), nonEntry);
}
auto requires = json["requires"];
for (auto i = requires.begin(); i != requires.end(); ++i)
lockFile.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
return lockFile;
}
nlohmann::json flakeEntryToJson(const LockFile::FlakeEntry & entry)
{
nlohmann::json json;
json["uri"] = entry.ref.to_string();
json["contentHash"] = entry.narHash.to_string(SRI);
for (auto & x : entry.nonFlakeEntries) {
json["nonFlakeRequires"][x.first]["uri"] = x.second.ref.to_string();
json["nonFlakeRequires"][x.first]["contentHash"] = x.second.narHash.to_string(SRI);
}
for (auto & x : entry.flakeEntries)
json["requires"][x.first.to_string()] = flakeEntryToJson(x.second);
return json;
}
void writeLockFile(const LockFile & lockFile, const Path & path)
{
nlohmann::json json;
json["version"] = 1;
json["nonFlakeRequires"] = nlohmann::json::object();
for (auto & x : lockFile.nonFlakeEntries) {
json["nonFlakeRequires"][x.first]["uri"] = x.second.ref.to_string();
json["nonFlakeRequires"][x.first]["contentHash"] = x.second.narHash.to_string(SRI);
}
json["requires"] = nlohmann::json::object();
for (auto & x : lockFile.flakeEntries)
json["requires"][x.first.to_string()] = flakeEntryToJson(x.second);
createDirs(dirOf(path));
writeFile(path, json.dump(4) + "\n"); // '4' = indentation in json file
}
std::shared_ptr<FlakeRegistry> EvalState::getGlobalFlakeRegistry()
{
std::call_once(_globalFlakeRegistryInit, [&]() {
auto path = evalSettings.flakeRegistry;
if (!hasPrefix(path, "/")) {
CachedDownloadRequest request(evalSettings.flakeRegistry);
request.name = "flake-registry.json";
request.gcRoot = true;
path = getDownloader()->downloadCached(store, request).path;
}
_globalFlakeRegistry = readRegistry(path);
});
return _globalFlakeRegistry;
}
Path getUserRegistryPath()
{
return getHome() + "/.config/nix/registry.json";
}
std::shared_ptr<FlakeRegistry> getUserRegistry()
{
return readRegistry(getUserRegistryPath());
}
std::shared_ptr<FlakeRegistry> getFlagRegistry(RegistryOverrides registryOverrides)
{
auto flagRegistry = std::make_shared<FlakeRegistry>();
for (auto const & x : registryOverrides) {
flagRegistry->entries.insert_or_assign(FlakeRef(x.first), FlakeRef(x.second));
}
return flagRegistry;
}
// This always returns a vector with flakeReg, userReg, globalReg.
// If one of them doesn't exist, the registry is left empty but does exist.
const Registries EvalState::getFlakeRegistries()
{
Registries registries;
registries.push_back(getFlagRegistry(registryOverrides));
registries.push_back(getUserRegistry());
registries.push_back(getGlobalFlakeRegistry());
return registries;
}
static FlakeRef lookupFlake(EvalState & state, const FlakeRef & flakeRef, const Registries & registries,
std::vector<FlakeRef> pastSearches = {});
FlakeRef updateFlakeRef(EvalState & state, const FlakeRef & newRef, const Registries & registries, std::vector<FlakeRef> pastSearches)
{
std::string errorMsg = "found cycle in flake registries: ";
for (FlakeRef oldRef : pastSearches) {
errorMsg += oldRef.to_string();
if (oldRef == newRef)
throw Error(errorMsg);
errorMsg += " - ";
}
pastSearches.push_back(newRef);
return lookupFlake(state, newRef, registries, pastSearches);
}
static FlakeRef lookupFlake(EvalState & state, const FlakeRef & flakeRef, const Registries & registries,
std::vector<FlakeRef> pastSearches)
{
if (registries.empty() && !flakeRef.isDirect())
throw Error("indirect flake reference '%s' is not allowed", flakeRef);
for (std::shared_ptr<FlakeRegistry> registry : registries) {
auto i = registry->entries.find(flakeRef);
if (i != registry->entries.end()) {
auto newRef = i->second;
return updateFlakeRef(state, newRef, registries, pastSearches);
}
auto j = registry->entries.find(flakeRef.baseRef());
if (j != registry->entries.end()) {
auto newRef = j->second;
newRef.ref = flakeRef.ref;
newRef.rev = flakeRef.rev;
return updateFlakeRef(state, newRef, registries, pastSearches);
}
}
if (!flakeRef.isDirect())
throw Error("could not resolve flake reference '%s'", flakeRef);
return flakeRef;
}
// Lookups happen here too
static SourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool impureIsAllowed = false)
{
FlakeRef resolvedRef = lookupFlake(state, flakeRef,
impureIsAllowed ? state.getFlakeRegistries() : std::vector<std::shared_ptr<FlakeRegistry>>());
if (evalSettings.pureEval && !impureIsAllowed && !resolvedRef.isImmutable())
throw Error("requested to fetch mutable flake '%s' in pure mode", resolvedRef);
// This only downloads only one revision of the repo, not the entire history.
if (auto refData = std::get_if<FlakeRef::IsGitHub>(&resolvedRef.data)) {
// FIXME: use regular /archive URLs instead? api.github.com
// might have stricter rate limits.
auto url = fmt("https://api.github.com/repos/%s/%s/tarball/%s",
refData->owner, refData->repo,
resolvedRef.rev ? resolvedRef.rev->to_string(Base16, false)
: resolvedRef.ref ? *resolvedRef.ref : "master");
std::string accessToken = settings.githubAccessToken.get();
if (accessToken != "")
url += "?access_token=" + accessToken;
CachedDownloadRequest request(url);
request.unpack = true;
request.name = "source";
request.ttl = resolvedRef.rev ? 1000000000 : settings.tarballTtl;
auto result = getDownloader()->downloadCached(state.store, request);
if (!result.etag)
throw Error("did not receive an ETag header from '%s'", url);
if (result.etag->size() != 42 || (*result.etag)[0] != '"' || (*result.etag)[41] != '"')
throw Error("ETag header '%s' from '%s' is not a Git revision", *result.etag, url);
FlakeRef ref(resolvedRef.baseRef());
ref.rev = Hash(std::string(*result.etag, 1, result.etag->size() - 2), htSHA1);
SourceInfo info(ref);
info.storePath = result.storePath;
info.narHash = state.store->queryPathInfo(info.storePath)->narHash;
return info;
}
// This downloads the entire git history
else if (auto refData = std::get_if<FlakeRef::IsGit>(&resolvedRef.data)) {
auto gitInfo = exportGit(state.store, refData->uri, resolvedRef.ref, resolvedRef.rev, "source");
FlakeRef ref(resolvedRef.baseRef());
ref.ref = gitInfo.ref;
ref.rev = gitInfo.rev;
SourceInfo info(ref);
info.storePath = gitInfo.storePath;
info.revCount = gitInfo.revCount;
info.narHash = state.store->queryPathInfo(info.storePath)->narHash;
return info;
}
else if (auto refData = std::get_if<FlakeRef::IsPath>(&resolvedRef.data)) {
if (!pathExists(refData->path + "/.git"))
throw Error("flake '%s' does not reference a Git repository", refData->path);
auto gitInfo = exportGit(state.store, refData->path, {}, {}, "source");
FlakeRef ref(resolvedRef.baseRef());
ref.ref = gitInfo.ref;
ref.rev = gitInfo.rev;
SourceInfo info(ref);
info.storePath = gitInfo.storePath;
info.revCount = gitInfo.revCount;
info.narHash = state.store->queryPathInfo(info.storePath)->narHash;
return info;
}
else abort();
}
// This will return the flake which corresponds to a given FlakeRef. The lookupFlake is done within `fetchFlake`, which is used here.
Flake getFlake(EvalState & state, const FlakeRef & flakeRef, bool impureIsAllowed = false)
{
SourceInfo sourceInfo = fetchFlake(state, flakeRef, impureIsAllowed);
debug("got flake source '%s' with flakeref %s", sourceInfo.storePath, sourceInfo.resolvedRef.to_string());
FlakeRef resolvedRef = sourceInfo.resolvedRef;
state.store->assertStorePath(sourceInfo.storePath);
if (state.allowedPaths)
state.allowedPaths->insert(state.store->toRealPath(sourceInfo.storePath));
// Guard against symlink attacks.
Path flakeFile = canonPath(sourceInfo.storePath + "/" + resolvedRef.subdir + "/flake.nix");
Path realFlakeFile = state.store->toRealPath(flakeFile);
if (!isInDir(realFlakeFile, state.store->toRealPath(sourceInfo.storePath)))
throw Error("'flake.nix' file of flake '%s' escapes from '%s'", resolvedRef, sourceInfo.storePath);
Flake flake(flakeRef, sourceInfo);
if (!pathExists(realFlakeFile))
throw Error("source tree referenced by '%s' does not contain a '%s/flake.nix' file", resolvedRef, resolvedRef.subdir);
Value vInfo;
state.evalFile(realFlakeFile, vInfo); // FIXME: symlink attack
state.forceAttrs(vInfo);
if (auto epoch = vInfo.attrs->get(state.symbols.create("epoch"))) {
flake.epoch = state.forceInt(*(**epoch).value, *(**epoch).pos);
if (flake.epoch > 2019)
throw Error("flake '%s' requires unsupported epoch %d; please upgrade Nix", flakeRef, flake.epoch);
} else
throw Error("flake '%s' lacks attribute 'epoch'", flakeRef);
if (auto name = vInfo.attrs->get(state.sName))
flake.id = state.forceStringNoCtx(*(**name).value, *(**name).pos);
else
throw Error("flake '%s' lacks attribute 'name'", flakeRef);
if (auto description = vInfo.attrs->get(state.sDescription))
flake.description = state.forceStringNoCtx(*(**description).value, *(**description).pos);
if (auto requires = vInfo.attrs->get(state.symbols.create("requires"))) {
state.forceList(*(**requires).value, *(**requires).pos);
for (unsigned int n = 0; n < (**requires).value->listSize(); ++n)
flake.requires.push_back(FlakeRef(state.forceStringNoCtx(
*(**requires).value->listElems()[n], *(**requires).pos)));
}
if (std::optional<Attr *> nonFlakeRequires = vInfo.attrs->get(state.symbols.create("nonFlakeRequires"))) {
state.forceAttrs(*(**nonFlakeRequires).value, *(**nonFlakeRequires).pos);
for (Attr attr : *(*(**nonFlakeRequires).value).attrs) {
std::string myNonFlakeUri = state.forceStringNoCtx(*attr.value, *attr.pos);
FlakeRef nonFlakeRef = FlakeRef(myNonFlakeUri);
flake.nonFlakeRequires.insert_or_assign(attr.name, nonFlakeRef);
}
}
if (auto provides = vInfo.attrs->get(state.symbols.create("provides"))) {
state.forceFunction(*(**provides).value, *(**provides).pos);
flake.vProvides = (**provides).value;
} else
throw Error("flake '%s' lacks attribute 'provides'", flakeRef);
return flake;
}
// Get the `NonFlake` corresponding to a `FlakeRef`.
NonFlake getNonFlake(EvalState & state, const FlakeRef & flakeRef, FlakeAlias alias, bool impureIsAllowed = false)
{
auto sourceInfo = fetchFlake(state, flakeRef, impureIsAllowed);
debug("got non-flake source '%s' with flakeref %s", sourceInfo.storePath, sourceInfo.resolvedRef.to_string());
FlakeRef resolvedRef = sourceInfo.resolvedRef;
NonFlake nonFlake(flakeRef, sourceInfo);
state.store->assertStorePath(nonFlake.sourceInfo.storePath);
if (state.allowedPaths)
state.allowedPaths->insert(nonFlake.sourceInfo.storePath);
nonFlake.alias = alias;
return nonFlake;
}
LockFile entryToLockFile(const LockFile::FlakeEntry & entry)
{
LockFile lockFile;
lockFile.flakeEntries = entry.flakeEntries;
lockFile.nonFlakeEntries = entry.nonFlakeEntries;
return lockFile;
}
LockFile::FlakeEntry dependenciesToFlakeEntry(const ResolvedFlake & resolvedFlake)
{
LockFile::FlakeEntry entry(resolvedFlake.flake.resolvedRef, resolvedFlake.flake.sourceInfo.narHash);
for (auto & info : resolvedFlake.flakeDeps)
entry.flakeEntries.insert_or_assign(info.first.to_string(), dependenciesToFlakeEntry(info.second));
for (auto & nonFlake : resolvedFlake.nonFlakeDeps) {
LockFile::NonFlakeEntry nonEntry(nonFlake.resolvedRef, nonFlake.sourceInfo.narHash);
entry.nonFlakeEntries.insert_or_assign(nonFlake.alias, nonEntry);
}
return entry;
}
bool allowedToWrite(HandleLockFile handle)
{
return handle == UpdateLockFile || handle == RecreateLockFile;
}
bool recreateLockFile(HandleLockFile handle)
{
return handle == RecreateLockFile || handle == UseNewLockFile;
}
bool allowedToUseRegistries(HandleLockFile handle, bool isTopRef)
{
if (handle == AllPure) return false;
else if (handle == TopRefUsesRegistries) return isTopRef;
else if (handle == UpdateLockFile) return true;
else if (handle == UseUpdatedLockFile) return true;
else if (handle == RecreateLockFile) return true;
else if (handle == UseNewLockFile) return true;
else assert(false);
}
ResolvedFlake resolveFlakeFromLockFile(EvalState & state, const FlakeRef & flakeRef,
HandleLockFile handleLockFile, LockFile lockFile = {}, bool topRef = false)
{
Flake flake = getFlake(state, flakeRef, allowedToUseRegistries(handleLockFile, topRef));
ResolvedFlake deps(flake);
for (auto & nonFlakeInfo : flake.nonFlakeRequires) {
FlakeRef ref = nonFlakeInfo.second;
auto i = lockFile.nonFlakeEntries.find(nonFlakeInfo.first);
if (i != lockFile.nonFlakeEntries.end()) {
NonFlake nonFlake = getNonFlake(state, i->second.ref, nonFlakeInfo.first);
if (nonFlake.sourceInfo.narHash != i->second.narHash)
throw Error("the content hash of flakeref '%s' doesn't match", i->second.ref.to_string());
deps.nonFlakeDeps.push_back(nonFlake);
} else {
if (handleLockFile == AllPure || handleLockFile == TopRefUsesRegistries)
throw Error("cannot update non-flake dependency '%s' in pure mode", nonFlakeInfo.first);
deps.nonFlakeDeps.push_back(getNonFlake(state, nonFlakeInfo.second, nonFlakeInfo.first, allowedToUseRegistries(handleLockFile, false)));
}
}
for (auto newFlakeRef : flake.requires) {
auto i = lockFile.flakeEntries.find(newFlakeRef);
if (i != lockFile.flakeEntries.end()) { // Propagate lockFile downwards if possible
ResolvedFlake newResFlake = resolveFlakeFromLockFile(state, i->second.ref, handleLockFile, entryToLockFile(i->second));
if (newResFlake.flake.sourceInfo.narHash != i->second.narHash)
throw Error("the content hash of flakeref '%s' doesn't match", i->second.ref.to_string());
deps.flakeDeps.insert_or_assign(newFlakeRef, newResFlake);
} else {
if (handleLockFile == AllPure || handleLockFile == TopRefUsesRegistries)
throw Error("cannot update flake dependency '%s' in pure mode", newFlakeRef.to_string());
deps.flakeDeps.insert_or_assign(newFlakeRef, resolveFlakeFromLockFile(state, newFlakeRef, handleLockFile));
}
}
return deps;
}
/* Given a flake reference, recursively fetch it and its dependencies.
FIXME: this should return a graph of flakes.
*/
ResolvedFlake resolveFlake(EvalState & state, const FlakeRef & topRef, HandleLockFile handleLockFile)
{
Flake flake = getFlake(state, topRef, allowedToUseRegistries(handleLockFile, true));
LockFile oldLockFile;
if (!recreateLockFile (handleLockFile)) {
// If recreateLockFile, start with an empty lockfile
oldLockFile = readLockFile(flake.sourceInfo.storePath + "/flake.lock"); // FIXME: symlink attack
}
LockFile lockFile(oldLockFile);
ResolvedFlake resFlake = resolveFlakeFromLockFile(state, topRef, handleLockFile, lockFile, true);
lockFile = entryToLockFile(dependenciesToFlakeEntry(resFlake));
if (!(lockFile == oldLockFile)) {
if (allowedToWrite(handleLockFile)) {
if (auto refData = std::get_if<FlakeRef::IsPath>(&topRef.data)) {
writeLockFile(lockFile, refData->path + (topRef.subdir == "" ? "" : "/" + topRef.subdir) + "/flake.lock");
// Hack: Make sure that flake.lock is visible to Git, so it ends up in the Nix store.
runProgram("git", true, { "-C", refData->path, "add",
(topRef.subdir == "" ? "" : topRef.subdir + "/") + "flake.lock" });
} else
warn("cannot write lockfile of remote flake '%s'", topRef);
} else if (handleLockFile != AllPure && handleLockFile != TopRefUsesRegistries)
warn("using updated lockfile without writing it to file");
}
return resFlake;
}
void updateLockFile(EvalState & state, const FlakeRef & flakeRef, bool recreateLockFile)
{
resolveFlake(state, flakeRef, recreateLockFile ? RecreateLockFile : UpdateLockFile);
}
void callFlake(EvalState & state, const ResolvedFlake & resFlake, Value & v)
{
// Construct the resulting attrset '{description, provides,
// ...}'. This attrset is passed lazily as an argument to 'provides'.
state.mkAttrs(v, resFlake.flakeDeps.size() + resFlake.nonFlakeDeps.size() + 8);
for (auto info : resFlake.flakeDeps) {
const ResolvedFlake newResFlake = info.second;
auto vFlake = state.allocAttr(v, newResFlake.flake.id);
callFlake(state, newResFlake, *vFlake);
}
for (const NonFlake nonFlake : resFlake.nonFlakeDeps) {
auto vNonFlake = state.allocAttr(v, nonFlake.alias);
state.mkAttrs(*vNonFlake, 4);
state.store->isValidPath(nonFlake.sourceInfo.storePath);
mkString(*state.allocAttr(*vNonFlake, state.sOutPath),
nonFlake.sourceInfo.storePath, {nonFlake.sourceInfo.storePath});
// FIXME: add rev, shortRev, revCount, ...
}
mkString(*state.allocAttr(v, state.sDescription), resFlake.flake.description);
auto & path = resFlake.flake.sourceInfo.storePath;
state.store->isValidPath(path);
mkString(*state.allocAttr(v, state.sOutPath), path, {path});
if (resFlake.flake.resolvedRef.rev) {
mkString(*state.allocAttr(v, state.symbols.create("rev")),
resFlake.flake.resolvedRef.rev->gitRev());
mkString(*state.allocAttr(v, state.symbols.create("shortRev")),
resFlake.flake.resolvedRef.rev->gitShortRev());
}
if (resFlake.flake.sourceInfo.revCount)
mkInt(*state.allocAttr(v, state.symbols.create("revCount")), *resFlake.flake.sourceInfo.revCount);
auto vProvides = state.allocAttr(v, state.symbols.create("provides"));
mkApp(*vProvides, *resFlake.flake.vProvides, v);
v.attrs->push_back(Attr(state.symbols.create("self"), &v));
v.attrs->sort();
}
// Return the `provides` of the top flake, while assigning to `v` the provides
// of the dependencies as well.
void makeFlakeValue(EvalState & state, const FlakeRef & flakeRef, HandleLockFile handle, Value & v)
{
callFlake(state, resolveFlake(state, flakeRef, handle), v);
}
// This function is exposed to be used in nix files.
static void prim_getFlake(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
makeFlakeValue(state, state.forceStringNoCtx(*args[0], pos),
evalSettings.pureEval ? AllPure : UseUpdatedLockFile, v);
}
static RegisterPrimOp r2("getFlake", 1, prim_getFlake);
void gitCloneFlake(FlakeRef flakeRef, EvalState & state, Registries registries, const Path & destDir)
{
flakeRef = lookupFlake(state, flakeRef, registries);
std::string uri;
Strings args = {"clone"};
if (auto refData = std::get_if<FlakeRef::IsGitHub>(&flakeRef.data)) {
uri = "git@github.com:" + refData->owner + "/" + refData->repo + ".git";
args.push_back(uri);
if (flakeRef.ref) {
args.push_back("--branch");
args.push_back(*flakeRef.ref);
}
} else if (auto refData = std::get_if<FlakeRef::IsGit>(&flakeRef.data)) {
args.push_back(refData->uri);
if (flakeRef.ref) {
args.push_back("--branch");
args.push_back(*flakeRef.ref);
}
}
if (destDir != "")
args.push_back(destDir);
runProgram("git", true, args);
}
}