Concurrent hydra-evaluator

This rewrites the top-level loop of hydra-evaluator in C++. The Perl
stuff is moved into hydra-eval-jobset. (Rewriting the entire evaluator
would be nice but is a bit too much work.) The new version has some
advantages:

* It can run multiple jobset evaluations in parallel.

* It uses PostgreSQL notifications so it doesn't have to poll the
  database. So if a jobset is triggered via the web interface or from
  a GitHub / Bitbucket webhook, evaluation of the jobset will start
  almost instantaneously (assuming the evaluator is not at its
  concurrency limit).

* It imposes a timeout on evaluations. So if e.g. hydra-eval-jobset
  hangs connecting to a Mercurial server, it will eventually be
  killed.
This commit is contained in:
Eelco Dolstra 2016-10-13 15:53:05 +02:00
parent 16feddd5d4
commit e0b2921ff2
15 changed files with 325 additions and 55 deletions

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@ -11,7 +11,7 @@ AC_PROG_LN_S
AC_PROG_LIBTOOL
AC_PROG_CXX
CXXFLAGS+=" -std=c++11"
CXXFLAGS+=" -std=c++17"
AC_PATH_PROG([XSLTPROC], [xsltproc])
@ -70,6 +70,7 @@ AC_CONFIG_FILES([
doc/Makefile
doc/manual/Makefile
src/Makefile
src/hydra-evaluator/Makefile
src/hydra-eval-jobs/Makefile
src/hydra-queue-runner/Makefile
src/sql/Makefile

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@ -58,8 +58,8 @@ rec {
src = fetchFromGitHub {
owner = "NixOS";
repo = "nix";
rev = "edf9eb8181e01f6b2123e5690019cfeeb44fc1c2";
sha256 = "1a00q9pypfziyi9hxl4rsammhwj7991wm4b1z9zcgl7zqksr3582";
rev = "5e61b422c58baac26b232233d39f5814cc35d52a";
sha256 = "0awic5zwibgpj5shpgjf2364imp2f84c8xi5r0x4p351q4kpg9z4";
};
buildInputs = attrs.buildInputs ++ [ autoreconfHook bison flex ];
nativeBuildInputs = attrs.nativeBuildInputs ++ [ aws-sdk-cpp' autoconf-archive ];
@ -124,6 +124,8 @@ rec {
src = if shell then null else hydraSrc;
stdenv = overrideCC stdenv gcc6;
buildInputs =
[ makeWrapper autoconf automake libtool unzip nukeReferences pkgconfig sqlite libpqxx
gitAndTools.topGit mercurial darcs subversion bazaar openssl bzip2 libxslt

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@ -1,3 +1,3 @@
SUBDIRS = hydra-eval-jobs hydra-queue-runner sql script lib root xsl ttf
SUBDIRS = hydra-evaluator hydra-eval-jobs hydra-queue-runner sql script lib root xsl ttf
BOOTCLEAN_SUBDIRS = $(SUBDIRS)
DIST_SUBDIRS = $(SUBDIRS)

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@ -0,0 +1,5 @@
bin_PROGRAMS = hydra-evaluator
hydra_evaluator_SOURCES = hydra-evaluator.cc
hydra_evaluator_LDADD = $(NIX_LIBS) -lpqxx
hydra_evaluator_CXXFLAGS = $(NIX_CFLAGS) -Wall -I ../libhydra

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@ -0,0 +1,275 @@
#include "shared.hh"
#include "db.hh"
#include "pool.hh"
#include <algorithm>
#include <thread>
#include <cstring>
#include <sys/types.h>
#include <sys/wait.h>
using namespace nix;
struct Evaluator
{
nix::Pool<Connection> dbPool;
typedef std::pair<std::string, std::string> JobsetName;
struct Jobset
{
JobsetName name;
time_t lastCheckedTime, triggerTime;
int checkInterval;
Pid pid;
};
typedef std::map<JobsetName, Jobset> Jobsets;
int evalTimeout = 3600;
size_t maxEvals = 4;
struct State
{
size_t runningEvals = 0;
Jobsets jobsets;
};
Sync<State> state_;
std::condition_variable childStarted;
std::condition_variable maybeDoWork;
const time_t notTriggered = std::numeric_limits<time_t>::max();
void readJobsets()
{
auto conn(dbPool.get());
pqxx::work txn(*conn);
auto res = txn.parameterized
("select project, j.name, lastCheckedTime, triggerTime, checkInterval from Jobsets j join Projects p on j.project = p.name "
"where j.enabled != 0 and p.enabled != 0").exec();
auto state(state_.lock());
std::set<JobsetName> seen;
for (auto const & row : res) {
auto name = JobsetName{row["project"].as<std::string>(), row["name"].as<std::string>()};
auto res = state->jobsets.try_emplace(name, Jobset{name});
auto & jobset = res.first->second;
jobset.lastCheckedTime = row["lastCheckedTime"].as<time_t>(0);
jobset.triggerTime = row["triggerTime"].as<time_t>(notTriggered);
jobset.checkInterval = row["checkInterval"].as<time_t>();
seen.insert(name);
}
for (auto i = state->jobsets.begin(); i != state->jobsets.end(); )
if (seen.count(i->first))
++i;
else {
printInfo("forgetting jobset %s:%s", i->first.first, i->first.second);
i = state->jobsets.erase(i);
}
}
void startEval(State & state, Jobset & jobset)
{
printInfo("starting evaluation of jobset %s:%s", jobset.name.first, jobset.name.second);
assert(jobset.pid == -1);
jobset.pid = startProcess([&]() {
Strings args = { "timeout", "-s", "KILL", std::to_string(evalTimeout), "hydra-eval-jobset", jobset.name.first, jobset.name.second };
execvp(args.front().c_str(), stringsToCharPtrs(args).data());
throw SysError(format("executing %1%") % args.front());
});
state.runningEvals++;
childStarted.notify_one();
time_t now = time(0);
{
auto conn(dbPool.get());
pqxx::work txn(*conn);
txn.parameterized
("update Jobsets set lastCheckedTime = $1, triggerTime = null where project = $2 and name = $3")
(now)
(jobset.name.first)
(jobset.name.second)
.exec();
txn.commit();
jobset.lastCheckedTime = now;
jobset.triggerTime = notTriggered;
}
}
void startEvals(State & state)
{
std::vector<Jobsets::iterator> sorted;
time_t now = time(0);
/* Filter out jobsets that have been evaluated recently and have
not been triggered. */
for (auto i = state.jobsets.begin(); i != state.jobsets.end(); ++i)
if (i->second.pid == -1 &&
(i->second.triggerTime != std::numeric_limits<time_t>::max() ||
(i->second.checkInterval > 0 && i->second.lastCheckedTime + i->second.checkInterval <= now)))
sorted.push_back(i);
/* Put jobsets in order of ascending trigger time, last checked
time, and name. */
std::sort(sorted.begin(), sorted.end(),
[](const Jobsets::iterator & a, const Jobsets::iterator & b) {
return
a->second.triggerTime != b->second.triggerTime
? a->second.triggerTime < b->second.triggerTime
: a->second.lastCheckedTime != b->second.lastCheckedTime
? a->second.lastCheckedTime < b->second.lastCheckedTime
: a->first < b->first;
});
/* Start jobset evaluations up to the concurrency limit.*/
for (auto & i : sorted) {
if (state.runningEvals >= maxEvals) break;
startEval(state, i->second);
}
}
void loop()
{
auto state(state_.lock());
while (true) {
time_t now = time(0);
std::chrono::seconds sleepTime = std::chrono::seconds::max();
if (state->runningEvals < maxEvals) {
for (auto & i : state->jobsets)
if (i.second.pid == -1 &&
i.second.checkInterval > 0)
sleepTime = std::min(sleepTime, std::chrono::seconds(
std::max((time_t) 1, i.second.lastCheckedTime - now + i.second.checkInterval)));
}
debug("waiting for %d s", sleepTime.count());
if (sleepTime == std::chrono::seconds::max())
state.wait(maybeDoWork);
else
state.wait_for(maybeDoWork, sleepTime);
startEvals(*state);
}
}
/* A thread that listens to PostgreSQL notifications about jobset
changes, updates the jobsets map, and signals the main thread
to start evaluations. */
void databaseMonitor()
{
while (true) {
try {
auto conn(dbPool.get());
receiver jobsetsAdded(*conn, "jobsets_added");
receiver jobsetsDeleted(*conn, "jobsets_deleted");
receiver jobsetsChanged(*conn, "jobset_scheduling_changed");
while (true) {
/* Note: we read/notify before
await_notification() to ensure we don't miss a
state change. */
readJobsets();
maybeDoWork.notify_one();
conn->await_notification();
printInfo("received jobset event");
}
} catch (std::exception & e) {
printError("exception in database monitor thread: %s", e.what());
sleep(30);
}
}
}
/* A thread that reaps child processes.*/
void reaper()
{
while (true) {
{
auto state(state_.lock());
while (!state->runningEvals)
state.wait(childStarted);
}
int status;
pid_t pid = waitpid(-1, &status, 0);
if (pid == -1) {
if (errno == EINTR) continue;
throw SysError("waiting for children");
}
{
auto state(state_.lock());
assert(state->runningEvals);
state->runningEvals--;
for (auto & jobset : state->jobsets)
if (jobset.second.pid == pid) {
printInfo("evaluation of jobset %s:%s finished with status %d",
jobset.first.first, jobset.first.second, status);
jobset.second.pid.release();
maybeDoWork.notify_one();
break;
}
}
}
}
void run()
{
std::thread reaperThread([&]() { reaper(); });
std::thread monitorThread([&]() { databaseMonitor(); });
while (true) {
try {
loop();
} catch (std::exception & e) {
printError("exception in main loop: %s", e.what());
sleep(30);
}
}
}
};
int main(int argc, char * * argv)
{
return handleExceptions(argv[0], [&]() {
initNix();
signal(SIGINT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
signal(SIGHUP, SIG_DFL);
parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
return false;
});
Evaluator().run();
});
}

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@ -4,5 +4,4 @@ hydra_queue_runner_SOURCES = hydra-queue-runner.cc queue-monitor.cc dispatcher.c
builder.cc build-result.cc build-remote.cc \
build-result.hh counter.hh token-server.hh state.hh db.hh
hydra_queue_runner_LDADD = $(NIX_LIBS) -lpqxx
AM_CXXFLAGS = $(NIX_CFLAGS) -Wall
hydra_queue_runner_CXXFLAGS = $(NIX_CFLAGS) -Wall -I ../libhydra

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@ -4,7 +4,7 @@ EXTRA_DIST = \
distributable_scripts = \
hydra-init \
hydra-evaluator \
hydra-eval-jobset \
hydra-server \
hydra-update-gc-roots \
hydra-s3-backup-collect-garbage \

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@ -345,47 +345,10 @@ sub checkJobset {
}
sub checkSomeJobset {
# If any jobset has been triggered by a push, check it.
my ($jobset) = $db->resultset('Jobsets')->search(
{ 'triggertime' => { '!=', undef } },
{ join => 'project', order_by => [ 'triggertime' ], rows => 1 });
die "syntax: $0 <PROJECT> <JOBSET>\n" unless @ARGV == 2;
# Otherwise, check the jobset that hasn't been checked for the
# longest time (but don't check more often than the jobset's
# minimal check interval).
($jobset) = $db->resultset('Jobsets')->search(
{ 'project.enabled' => 1, 'me.enabled' => { '!=' => 0 },
, 'checkinterval' => { '!=', 0 }
, -or => [ 'lastcheckedtime' => undef, 'lastcheckedtime' => { '<', \ (time() . " - me.checkinterval") } ] },
{ join => 'project', order_by => [ 'lastcheckedtime nulls first' ], rows => 1 })
unless defined $jobset;
return 0 unless defined $jobset;
return system($0, $jobset->project->name, $jobset->name) == 0;
}
if (scalar @ARGV == 2) {
my $projectName = $ARGV[0];
my $jobsetName = $ARGV[1];
my $jobset = $db->resultset('Jobsets')->find($projectName, $jobsetName) or
my $projectName = $ARGV[0];
my $jobsetName = $ARGV[1];
my $jobset = $db->resultset('Jobsets')->find($projectName, $jobsetName) or
die "$0: specified jobset \"$projectName:$jobsetName\" does not exist\n";
exit checkJobset($jobset);
}
while (1) {
eval {
if (checkSomeJobset) {
# Just so we don't go completely crazy if lastcheckedtime
# isn't updated properly.
sleep 1;
} else {
# print STDERR "sleeping...\n";
sleep 30;
}
};
if ($@) { print STDERR "$@"; }
}
exit checkJobset($jobset);

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@ -83,6 +83,19 @@ create function notifyJobsetSharesChanged() returns trigger as 'begin notify job
create trigger JobsetSharesChanged after update on Jobsets for each row
when (old.schedulingShares != new.schedulingShares) execute procedure notifyJobsetSharesChanged();
create function notifyJobsetsAdded() returns trigger as 'begin notify jobsets_added; return null; end;' language plpgsql;
create trigger JobsetsAdded after insert on Jobsets execute procedure notifyJobsetsAdded();
create function notifyJobsetsDeleted() returns trigger as 'begin notify jobsets_deleted; return null; end;' language plpgsql;
create trigger JobsetsDeleted after delete on Jobsets execute procedure notifyJobsetsDeleted();
create function notifyJobsetSchedulingChanged() returns trigger as 'begin notify jobset_scheduling_changed; return null; end;' language plpgsql;
create trigger JobsetSchedulingChanged after update on Jobsets for each row
when (((old.triggerTime is distinct from new.triggerTime) and (new.triggerTime is not null))
or old.checkInterval != new.checkInterval
or old.enabled != new.enabled)
execute procedure notifyJobsetSchedulingChanged();
#endif

12
src/sql/upgrade-50.sql Normal file
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@ -0,0 +1,12 @@
create function notifyJobsetsAdded() returns trigger as 'begin notify jobsets_added; return null; end;' language plpgsql;
create trigger JobsetsAdded after insert on Jobsets execute procedure notifyJobsetsAdded();
create function notifyJobsetsDeleted() returns trigger as 'begin notify jobsets_deleted; return null; end;' language plpgsql;
create trigger JobsetsDeleted after delete on Jobsets execute procedure notifyJobsetsDeleted();
create function notifyJobsetSchedulingChanged() returns trigger as 'begin notify jobset_scheduling_changed; return null; end;' language plpgsql;
create trigger JobsetSchedulingChanged after update on Jobsets for each row
when ((old.triggerTime is distinct from new.triggerTime) and (new.triggerTime is not null))
or old.checkInterval != new.checkInterval
or old.enabled != new.enabled
execute procedure notifyJobsetSchedulingChanged();

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@ -13,7 +13,7 @@ TESTS_ENVIRONMENT = \
NIX_LOG_DIR="$(abs_builddir)/nix/var/log/nix" \
NIX_BUILD_HOOK= \
PERL5LIB="$(srcdir):$(top_srcdir)/src/lib:$$PERL5LIB" \
PATH=$(abs_top_srcdir)/src/script:$(abs_top_srcdir)/src/hydra-eval-jobs:$(abs_top_srcdir)/src/hydra-queue-runner:$$PATH \
PATH=$(abs_top_srcdir)/src/hydra-evaluator:$(abs_top_srcdir)/src/script:$(abs_top_srcdir)/src/hydra-eval-jobs:$(abs_top_srcdir)/src/hydra-queue-runner:$$PATH \
perl -w
EXTRA_DIST = \

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@ -61,7 +61,7 @@ sub createJobsetWithOneInput {
sub evalSucceeds {
my ($jobset) = @_;
my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-evaluator", $jobset->project->name, $jobset->name));
my ($res, $stdout, $stderr) = captureStdoutStderr(60, ("hydra-eval-jobset", $jobset->project->name, $jobset->name));
chomp $stdout; chomp $stderr;
print STDERR "Evaluation errors for jobset ".$jobset->project->name.":".$jobset->name.": \n".$jobset->errormsg."\n" if $jobset->errormsg;
print STDERR "STDOUT: $stdout\n" if $stdout ne "";

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@ -49,14 +49,14 @@ ok(exists $jobset->{jobsetinputs}->{"my-src"}, "The new jobset has a 'my-src' in
ok($jobset->{jobsetinputs}->{"my-src"}->{jobsetinputalts}->[0] eq "/run/jobset", "The 'my-src' input is in /run/jobset");
system("hydra-evaluator sample default");
system("hydra-eval-jobset sample default");
$result = request_json({ uri => '/jobset/sample/default/evals' });
ok($result->code() == 200, "Can get evals of a jobset");
my $evals = decode_json($result->content())->{evals};
my $eval = $evals->[0];
ok($eval->{hasnewbuilds} == 1, "The first eval of a jobset has new builds");
system("echo >> /run/jobset/default.nix; hydra-evaluator sample default");
system("echo >> /run/jobset/default.nix; hydra-eval-jobset sample default");
my $evals = decode_json(request_json({ uri => '/jobset/sample/default/evals' })->content())->{evals};
ok($evals->[0]->{jobsetevalinputs}->{"my-src"}->{revision} != $evals->[1]->{jobsetevalinputs}->{"my-src"}->{revision}, "Changing a jobset source changes its revision");

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@ -19,7 +19,7 @@ my $jobsetinput;
$jobsetinput = $jobset->jobsetinputs->create({name => "jobs", type => "path"});
$jobsetinput->jobsetinputalts->create({altnr => 0, value => getcwd . "/jobs"});
system("hydra-evaluator " . $jobset->project->name . " " . $jobset->name);
system("hydra-eval-jobset " . $jobset->project->name . " " . $jobset->name);
my $successful_hash;
foreach my $build ($jobset->builds->search({finished => 0})) {