Hack to get SSH error messages from build-remote

E.g.

  cannot build on 'ssh://mac1': cannot connect to 'mac1': bash: nix-store: command not found
  cannot build on 'ssh://mac2': cannot connect to 'mac2': Host key verification failed.
  cannot build on 'ssh://mac3': cannot connect to 'mac3': Received disconnect from 213... port 6001:2: Too many authentication failures
  Authentication failed.
This commit is contained in:
Eelco Dolstra 2018-03-20 15:17:59 +01:00
parent 78d0c72b52
commit 1aca195e52
No known key found for this signature in database
GPG key ID: 8170B4726D7198DE
4 changed files with 33 additions and 7 deletions

View file

@ -191,8 +191,10 @@ int main (int argc, char * * argv)
storeUri = bestMachine->storeUri; storeUri = bestMachine->storeUri;
} catch (std::exception & e) { } catch (std::exception & e) {
printError("unable to open SSH connection to '%s': %s; trying other available machines...", auto msg = chomp(drainFD(5, false));
bestMachine->storeUri, e.what()); printError("cannot build on '%s': %s%s",
bestMachine->storeUri, e.what(),
(msg.empty() ? "" : ": " + msg));
bestMachine->enabled = false; bestMachine->enabled = false;
continue; continue;
} }
@ -202,6 +204,8 @@ int main (int argc, char * * argv)
} }
connected: connected:
close(5);
std::cerr << "# accept\n" << storeUri << "\n"; std::cerr << "# accept\n" << storeUri << "\n";
auto inputs = readStrings<PathSet>(source); auto inputs = readStrings<PathSet>(source);

View file

@ -652,6 +652,11 @@ HookInstance::HookInstance()
if (dup2(builderOut.writeSide.get(), 4) == -1) if (dup2(builderOut.writeSide.get(), 4) == -1)
throw SysError("dupping builder's stdout/stderr"); throw SysError("dupping builder's stdout/stderr");
/* Hack: pass the read side of that fd to allow build-remote
to read SSH error messages. */
if (dup2(builderOut.readSide.get(), 5) == -1)
throw SysError("dupping builder's stdout/stderr");
Strings args = { Strings args = {
baseNameOf(settings.buildHook), baseNameOf(settings.buildHook),
std::to_string(verbosity), std::to_string(verbosity),

View file

@ -567,21 +567,38 @@ void writeFull(int fd, const string & s, bool allowInterrupts)
} }
string drainFD(int fd) string drainFD(int fd, bool block)
{ {
StringSink sink; StringSink sink;
drainFD(fd, sink); drainFD(fd, sink, block);
return std::move(*sink.s); return std::move(*sink.s);
} }
void drainFD(int fd, Sink & sink) void drainFD(int fd, Sink & sink, bool block)
{ {
int saved;
Finally finally([&]() {
if (!block) {
if (fcntl(fd, F_SETFL, saved) == -1)
throw SysError("making file descriptor blocking");
}
});
if (!block) {
saved = fcntl(fd, F_GETFL);
if (fcntl(fd, F_SETFL, saved | O_NONBLOCK) == -1)
throw SysError("making file descriptor non-blocking");
}
std::vector<unsigned char> buf(4096); std::vector<unsigned char> buf(4096);
while (1) { while (1) {
checkInterrupt(); checkInterrupt();
ssize_t rd = read(fd, buf.data(), buf.size()); ssize_t rd = read(fd, buf.data(), buf.size());
if (rd == -1) { if (rd == -1) {
if (!block && (errno == EAGAIN || errno == EWOULDBLOCK))
break;
if (errno != EINTR) if (errno != EINTR)
throw SysError("reading from file"); throw SysError("reading from file");
} }

View file

@ -151,9 +151,9 @@ MakeError(EndOfFile, Error)
/* Read a file descriptor until EOF occurs. */ /* Read a file descriptor until EOF occurs. */
string drainFD(int fd); string drainFD(int fd, bool block = true);
void drainFD(int fd, Sink & sink); void drainFD(int fd, Sink & sink, bool block = true);
/* Automatic cleanup of resources. */ /* Automatic cleanup of resources. */