Plugins: Add isEnabled method

Plugins are now disabled at startup time unless there is some relevant
configuration in hydra.conf. This avoids hydra-notify having to do a
lot of redundant work (a lot of plugins did a lot of database queries
*before* deciding they were disabled).

Note: BitBucketStatus users will need to add 'enable_bitbucket_status
= 1' to hydra.conf.

src/lib/Hydra/Plugin.pm

@@ -12,11 +12,15 @@ sub new {
     return $self;
 }
 
+sub isEnabled {
+    return 1;
+}
+
 sub instantiate {
     my ($class, %args) = @_;
     my $plugins = [];
     $args{plugins} = $plugins;
-    push @$plugins, $class->plugins(%args);
+    push @$plugins, grep { $_->isEnabled } $class->plugins(%args);
     return @$plugins;
 }
 

src/lib/Hydra/Plugin/BitBucketStatus.pm

@@ -7,6 +7,11 @@ use JSON;
 use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 
+sub isEnabled {
+    my ($self) = @_;
+    return $self->{config}->{enable_bitbucket_status} == 1;
+}
+
 sub toBitBucketState {
     my ($buildStatus) = @_;
     if ($buildStatus == 0) {

src/lib/Hydra/Plugin/CircleCINotification.pm

@@ -7,6 +7,11 @@ use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 use JSON;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{circleci};
+}
+
 sub buildFinished {
     my ($self, $build, $dependents) = @_;
     my $cfg = $self->{config}->{circleci};

src/lib/Hydra/Plugin/CoverityScan.pm

@@ -6,6 +6,11 @@ use File::Basename;
 use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{coverityscan};
+}
+
 sub buildFinished {
     my ($self, $b, $dependents) = @_;
 

src/lib/Hydra/Plugin/EmailNotification.pm

@@ -9,6 +9,10 @@ use Hydra::Helper::Nix;
 use Hydra::Helper::CatalystUtils;
 use Hydra::Helper::Email;
 
+sub isEnabled {
+    my ($self) = @_;
+    return $self->{config}->{email_notification} == 1;
+}
 
 my $template = <<EOF;
 Hi,
@@ -44,8 +48,6 @@ EOF
 sub buildFinished {
     my ($self, $build, $dependents) = @_;
 
-    return unless $self->{config}->{email_notification} // 0;
-
     die unless $build->finished;
 
     # Figure out to whom to send notification for each build.  For

src/lib/Hydra/Plugin/GithubStatus.pm

@@ -8,6 +8,11 @@ use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 use List::Util qw(max);
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{githubstatus};
+}
+
 sub toGithubState {
     my ($buildStatus) = @_;
     if ($buildStatus == 0) {

src/lib/Hydra/Plugin/GitlabStatus.pm

@@ -16,6 +16,11 @@ use List::Util qw(max);
 #   - gitlab_project_id => ID of the project in Gitlab, i.e. in the above
 #     case the ID in gitlab of "nixexprs"
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{gitlab_authorization};
+}
+
 sub toGitlabState {
     my ($status, $buildStatus) = @_;
     if ($status == 0) {

src/lib/Hydra/Plugin/HipChatNotification.pm

@@ -5,6 +5,11 @@ use parent 'Hydra::Plugin';
 use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{hipchat};
+}
+
 sub buildFinished {
     my ($self, $build, $dependents) = @_;
 

src/lib/Hydra/Plugin/InfluxDBNotification.pm

@@ -7,6 +7,11 @@ use HTTP::Request;
 use LWP::UserAgent;
 # use Hydra::Helper::CatalystUtils;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{influxdb};
+}
+
 sub toBuildStatusDetailed {
     my ($buildStatus) = @_;
     if ($buildStatus == 0) {

src/lib/Hydra/Plugin/RunCommand.pm

@@ -5,6 +5,11 @@ use parent 'Hydra::Plugin';
 use experimental 'smartmatch';
 use JSON;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{runcommand};
+}
+
 sub configSectionMatches {
     my ($name, $project, $jobset, $job) = @_;
 

src/lib/Hydra/Plugin/S3Backup.pm

@@ -14,6 +14,11 @@ use Nix::Store;
 use Hydra::Model::DB;
 use Hydra::Helper::CatalystUtils;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{s3backup};
+}
+
 my $client;
 my %compressors = (
     xz => "| $Nix::Config::xz",

src/lib/Hydra/Plugin/SlackNotification.pm

@@ -7,6 +7,11 @@ use LWP::UserAgent;
 use Hydra::Helper::CatalystUtils;
 use JSON;
 
+sub isEnabled {
+    my ($self) = @_;
+    return defined $self->{config}->{slack};
+}
+
 sub renderDuration {
     my ($build) = @_;
     my $duration = $build->stoptime - $build->starttime;