statsd: add a chance to set hostname and port in hydra.conf

Co-authored-by: Graham Christensen <graham@grahamc.com>

doc/manual/src/installation.md

@@ -187,6 +187,18 @@ following:
         }
     }
 
+Statsd Configuration
+--------------------
+
+By default, Hydra will send stats to statsd at `localhost:8125`. Point Hydra to a different server via:
+
+```
+<statsd>
+  host = alternative.host
+  port = 18125
+</statsd>
+```
+
 Using LDAP as authentication backend (optional)
 -----------------------------------------------
 

src/lib/Hydra/Helper/Nix.pm

@@ -15,7 +15,7 @@ use IPC::Run;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(
     getHydraHome getHydraConfig getBaseUrl
-    getSCMCacheDir
+    getSCMCacheDir getStatsdConfig
     registerRoot getGCRootsDir gcRootFor
     jobsetOverview jobsetOverview_
     getDrvLogPath findLog
@@ -55,6 +55,23 @@ sub getHydraConfig {
 }
 
 
+# Return hash of statsd configuration of the following shape:
+# (
+#   host => string,
+#   port => digit
+# )
+sub getStatsdConfig {
+    my ($config) = @_;
+    my $cfg = $config->{statsd};
+    my %statsd = defined $cfg ? ref $cfg eq "HASH" ? %$cfg : ($cfg) : ();
+
+    return {
+        "host" => %statsd{'host'}  // 'localhost',
+        "port" => %statsd{'port'}  // 8125,
+    }
+}
+
+
 sub getBaseUrl {
     my ($config) = @_;
     return $config->{'base_uri'} // "http://" . hostname_long . ":3000";

src/script/hydra-eval-jobset

@@ -33,6 +33,10 @@ my $plugins = [Hydra::Plugin->instantiate(db => $db, config => $config)];
 
 my $dryRun = defined $ENV{'HYDRA_DRY_RUN'};
 
+my $statsdConfig = Hydra::Helper::Nix::getStatsdConfig($config);
+$Net::Statsd::HOST = $statsdConfig->{'host'};
+$Net::Statsd::PORT = $statsdConfig->{'port'};
+
 alarm 3600; # FIXME: make configurable
 
 

src/script/hydra-send-stats

@@ -9,6 +9,11 @@ use JSON;
 STDERR->autoflush(1);
 binmode STDERR, ":encoding(utf8)";
 
+my $config = getHydraConfig();
+my $statsdConfig = Hydra::Helper::Nix::getStatsdConfig($config);
+$Net::Statsd::HOST = $statsdConfig->{'host'};
+$Net::Statsd::PORT = $statsdConfig->{'port'};
+
 sub gauge {
     my ($name, $val) = @_;
     die unless defined $val;

t/Config/statsd.t

@@ -0,0 +1,61 @@
+use strict;
+use Setup;
+
+my %ctx = test_init(hydra_config => q|
+<statsd>
+  host = foo.bar
+  port = 18125
+</statsd>
+|);
+
+require Hydra::Helper::Nix;
+use Test2::V0;
+
+is(Hydra::Helper::Nix::getStatsdConfig(Hydra::Helper::Nix::getHydraConfig()), {
+    'host' => "foo.bar",
+    'port' => 18125
+}, "Reading specific configuration from the hydra.conf works");
+
+is(Hydra::Helper::Nix::getStatsdConfig(), {
+    'host' => "localhost",
+    'port' => 8125
+}, "A totally empty configuration yields default options");
+
+is(Hydra::Helper::Nix::getStatsdConfig({
+    "statsd" => {
+
+    }
+}), {
+    'host' => "localhost",
+    'port' => 8125
+}, "A empty statsd block yields default options");
+
+is(Hydra::Helper::Nix::getStatsdConfig({
+    "statsd" => {
+        'host' => "statsdhost"
+    }
+}), {
+    'host' => "statsdhost",
+    'port' => 8125
+}, "An overridden statsd host propogates, but the other defaults are returned");
+
+is(Hydra::Helper::Nix::getStatsdConfig({
+    "statsd" => {
+        'port' => 5218
+    }
+}), {
+    'host' => "localhost",
+    'port' => 5218
+}, "An overridden statsd port propogates, but the other defaults are returned");
+
+is(Hydra::Helper::Nix::getStatsdConfig({
+    "statsd" => {
+        'host' => 'my.statsd.host',
+        'port' => 5218
+    }
+}), {
+    'host' => "my.statsd.host",
+    'port' => 5218
+}, "An overridden statsd port and host propogate");
+
+done_testing;