From 7aa52517e9f8415da833e50d5827035775f9ce9a Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 25 Aug 2015 14:11:50 +0200
Subject: [PATCH] Support multiple machines files
This is primarily useful for the Hydra provisioner, which can write
its machines to another file than /etc/nix/machines.
---
src/hydra-queue-runner/hydra-queue-runner.cc | 79 ++++++++++++++------
src/hydra-queue-runner/state.hh | 6 +-
src/lib/Hydra/Helper/Nix.pm | 12 +--
3 files changed, 63 insertions(+), 34 deletions(-)
diff --git a/src/hydra-queue-runner/hydra-queue-runner.cc b/src/hydra-queue-runner/hydra-queue-runner.cc
index 1f3380f4..dc363077 100644
--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@@ -22,33 +22,14 @@ State::State()
logDir = canonPath(hydraData + "/build-logs");
- machinesFile = getEnv("NIX_REMOTE_SYSTEMS", "/etc/nix/machines");
- machinesFileStat.st_ino = 0;
- machinesFileStat.st_mtime = 0;
-
localPlatforms = {settings.thisSystem};
if (settings.thisSystem == "x86_64-linux")
localPlatforms.insert("i686-linux");
}
-void State::loadMachinesFile()
+void State::parseMachines(const std::string & contents)
{
- string contents;
- if (pathExists(machinesFile)) {
- struct stat st;
- if (stat(machinesFile.c_str(), &st) != 0)
- throw SysError(format("getting stats about ‘%1%’") % machinesFile);
- if (st.st_ino == machinesFileStat.st_ino && st.st_mtime == machinesFileStat.st_mtime)
- return;
- printMsg(lvlDebug, "reloading machines");
- contents = readFile(machinesFile);
- machinesFileStat = st;
- } else {
- contents = "localhost " + concatStringsSep(",", localPlatforms)
- + " - " + int2String(settings.maxBuildJobs) + " 1";
- }
-
Machines newMachines, oldMachines;
{
auto machines_(machines.lock());
@@ -103,11 +84,63 @@ void State::loadMachinesFile()
void State::monitorMachinesFile()
{
+ string defaultMachinesFile = "/etc/nix/machines";
+ auto machinesFiles = tokenizeString<std::vector<Path>>(
+ getEnv("NIX_REMOTE_SYSTEMS", pathExists(defaultMachinesFile) ? defaultMachinesFile : ""), ":");
+
+ if (machinesFiles.empty()) {
+ parseMachines("localhost " + concatStringsSep(",", localPlatforms)
+ + " - " + int2String(settings.maxBuildJobs) + " 1");
+ return;
+ }
+
+ std::vector<struct stat> fileStats;
+ fileStats.resize(machinesFiles.size());
+ for (unsigned int n = 0; n < machinesFiles.size(); ++n) {
+ auto & st(fileStats[n]);
+ st.st_ino = st.st_mtime = 0;
+ }
+
+ auto readMachinesFiles = [&]() {
+
+ /* Check if any of the machines files changed. */
+ bool anyChanged = false;
+ for (unsigned int n = 0; n < machinesFiles.size(); ++n) {
+ Path machinesFile = machinesFiles[n];
+ struct stat st;
+ if (stat(machinesFile.c_str(), &st) != 0) {
+ if (errno != ENOENT)
+ throw SysError(format("getting stats about ‘%1%’") % machinesFile);
+ st.st_ino = st.st_mtime = 0;
+ }
+ auto & old(fileStats[n]);
+ if (old.st_ino != st.st_ino || old.st_mtime != st.st_mtime)
+ anyChanged = true;
+ old = st;
+ }
+
+ if (!anyChanged) return;
+
+ debug("reloading machines files");
+
+ string contents;
+ for (auto & machinesFile : machinesFiles) {
+ try {
+ contents += readFile(machinesFile);
+ contents += '\n';
+ } catch (SysError & e) {
+ if (e.errNo != ENOENT) throw;
+ }
+ }
+
+ parseMachines(contents);
+ };
+
while (true) {
try {
+ readMachinesFiles();
// FIXME: use inotify.
- sleep(60);
- loadMachinesFile();
+ sleep(30);
} catch (std::exception & e) {
printMsg(lvlError, format("reloading machines file: %1%") % e.what());
}
@@ -587,8 +620,6 @@ void State::run(BuildID buildOne)
dumpStatus(*conn, false);
}
- loadMachinesFile();
-
std::thread(&State::monitorMachinesFile, this).detach();
std::thread(&State::queueMonitor, this).detach();
diff --git a/src/hydra-queue-runner/state.hh b/src/hydra-queue-runner/state.hh
index 2a11f6a4..e5f50e36 100644
--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@@ -286,9 +286,6 @@ private:
typedef std::map<std::string, Machine::ptr> Machines;
Sync<Machines> machines; // FIXME: use atomic_shared_ptr
- nix::Path machinesFile;
- struct stat machinesFileStat;
-
/* Various stats. */
time_t startedAt;
counter nrBuildsRead{0};
@@ -352,8 +349,7 @@ private:
void clearBusy(Connection & conn, time_t stopTime);
- /* (Re)load /etc/nix/machines. */
- void loadMachinesFile();
+ void parseMachines(const std::string & contents);
/* Thread to reload /etc/nix/machines periodically. */
void monitorMachinesFile();
diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index 3a898745..bd0f1ceb 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -286,12 +286,13 @@ sub getEvals {
sub getMachines {
- my $machinesConf = $ENV{"NIX_REMOTE_SYSTEMS"} || "/etc/nix/machines";
-
- # Read the list of machines.
my %machines = ();
- if (-e $machinesConf) {
- open CONF, "<$machinesConf" or die;
+
+ my @machinesFiles = split /:/, ($ENV{"NIX_REMOTE_SYSTEMS"} || "/etc/nix/machines");
+
+ for my $machinesFile (@machinesFiles) {
+ next unless -e $machinesFile;
+ open CONF, "<$machinesFile" or die;
while (<CONF>) {
chomp;
s/\#.*$//g;
@@ -310,6 +311,7 @@ sub getMachines {
}
close CONF;
}
+
return \%machines;
}