Write to InfluxDB directly via UDP

This removes the need for Sidekiq and any overhead/problems introduced
by TCP. There are a few things to take into account:

1. When writing data to InfluxDB you may still get an error if the
   server becomes unavailable during the write. Because of this we're
   catching all exceptions and just ignore them (for now).
2. Writing via UDP apparently requires the timestamp to be in
   nanoseconds. Without this data either isn't written properly.
3. Due to the restrictions on UDP buffer sizes we're writing metrics one
   by one, instead of writing all of them at once.

3 files changed, 51 insertions, 41 deletions

diff --git a/db/migrate/20151229102248_influxdb_udp_port_setting.rb b/db/migrate/20151229102248_influxdb_udp_port_setting.rb
new file mode 100644
index 00000000000..ae0499f936d
--- /dev/null
+++ b/db/migrate/20151229102248_influxdb_udp_port_setting.rb
@@ -0,0 +1,5 @@
+class InfluxdbUdpPortSetting < ActiveRecord::Migration
+  def change
+    add_column :application_settings, :metrics_port, :integer, default: 8089
+  end
+end
diff --git a/db/migrate/20151229112614_influxdb_remote_database_setting.rb b/db/migrate/20151229112614_influxdb_remote_database_setting.rb
new file mode 100644
index 00000000000..f0e1ee1e7a7
--- /dev/null
+++ b/db/migrate/20151229112614_influxdb_remote_database_setting.rb
@@ -0,0 +1,5 @@
+class InfluxdbRemoteDatabaseSetting < ActiveRecord::Migration
+  def change
+    remove_column :application_settings, :metrics_database
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ac6bd905eea..df7f72d5ad4 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20151228175719) do
+ActiveRecord::Schema.define(version: 20151229112614) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -33,36 +33,36 @@ ActiveRecord::Schema.define(version: 20151228175719) do
     t.datetime "created_at"
     t.datetime "updated_at"
     t.string   "home_page_url"
-    t.integer  "default_branch_protection",    default: 2
-    t.boolean  "twitter_sharing_enabled",      default: true
+    t.integer  "default_branch_protection",         default: 2
+    t.boolean  "twitter_sharing_enabled",           default: true
     t.text     "restricted_visibility_levels"
-    t.boolean  "version_check_enabled",        default: true
-    t.integer  "max_attachment_size",          default: 10,    null: false
+    t.boolean  "version_check_enabled",             default: true
+    t.integer  "max_attachment_size",               default: 10,          null: false
     t.integer  "default_project_visibility"
     t.integer  "default_snippet_visibility"
     t.text     "restricted_signup_domains"
-    t.boolean  "user_oauth_applications",      default: true
+    t.boolean  "user_oauth_applications",           default: true
     t.string   "after_sign_out_path"
-    t.integer  "session_expire_delay",         default: 10080, null: false
+    t.integer  "session_expire_delay",              default: 10080,       null: false
     t.text     "import_sources"
     t.text     "help_page_text"
     t.string   "admin_notification_email"
-    t.boolean  "shared_runners_enabled",       default: true,  null: false
-    t.integer  "max_artifacts_size",           default: 100,   null: false
+    t.boolean  "shared_runners_enabled",            default: true,        null: false
+    t.integer  "max_artifacts_size",                default: 100,         null: false
     t.string   "runners_registration_token"
-    t.boolean  "require_two_factor_authentication",             default: false
-    t.integer  "two_factor_grace_period",                       default: 48
-    t.boolean  "metrics_enabled",                               default: false
-    t.string   "metrics_host",                                  default: "localhost"
-    t.string   "metrics_database",                              default: "gitlab"
+    t.boolean  "require_two_factor_authentication", default: false
+    t.integer  "two_factor_grace_period",           default: 48
+    t.boolean  "metrics_enabled",                   default: false
+    t.string   "metrics_host",                      default: "localhost"
     t.string   "metrics_username"
     t.string   "metrics_password"
-    t.integer  "metrics_pool_size",                             default: 16
-    t.integer  "metrics_timeout",                               default: 10
-    t.integer  "metrics_method_call_threshold",                 default: 10
+    t.integer  "metrics_pool_size",                 default: 16
+    t.integer  "metrics_timeout",                   default: 10
+    t.integer  "metrics_method_call_threshold",     default: 10
     t.boolean  "recaptcha_enabled",                 default: false
     t.string   "recaptcha_site_key"
     t.string   "recaptcha_private_key"
+    t.integer  "metrics_port",                      default: 8089
   end
 
   create_table "audit_events", force: :cascade do |t|
@@ -796,12 +796,12 @@ ActiveRecord::Schema.define(version: 20151228175719) do
   add_index "tags", ["name"], name: "index_tags_on_name", unique: true, using: :btree
 
   create_table "users", force: :cascade do |t|
-    t.string   "email",                      default: "",    null: false
-    t.string   "encrypted_password",         default: "",    null: false
+    t.string   "email",                       default: "",    null: false
+    t.string   "encrypted_password",          default: "",    null: false
     t.string   "reset_password_token"
     t.datetime "reset_password_sent_at"
     t.datetime "remember_created_at"
-    t.integer  "sign_in_count",              default: 0
+    t.integer  "sign_in_count",               default: 0
     t.datetime "current_sign_in_at"
     t.datetime "last_sign_in_at"
     t.string   "current_sign_in_ip"
@@ -809,22 +809,22 @@ ActiveRecord::Schema.define(version: 20151228175719) do
     t.datetime "created_at"
     t.datetime "updated_at"
     t.string   "name"
-    t.boolean  "admin",                      default: false, null: false
-    t.integer  "projects_limit",             default: 10
-    t.string   "skype",                      default: "",    null: false
-    t.string   "linkedin",                   default: "",    null: false
-    t.string   "twitter",                    default: "",    null: false
+    t.boolean  "admin",                       default: false, null: false
+    t.integer  "projects_limit",              default: 10
+    t.string   "skype",                       default: "",    null: false
+    t.string   "linkedin",                    default: "",    null: false
+    t.string   "twitter",                     default: "",    null: false
     t.string   "authentication_token"
-    t.integer  "theme_id",                   default: 1,     null: false
+    t.integer  "theme_id",                    default: 1,     null: false
     t.string   "bio"
-    t.integer  "failed_attempts",            default: 0
+    t.integer  "failed_attempts",             default: 0
     t.datetime "locked_at"
     t.string   "username"
-    t.boolean  "can_create_group",           default: true,  null: false
-    t.boolean  "can_create_team",            default: true,  null: false
+    t.boolean  "can_create_group",            default: true,  null: false
+    t.boolean  "can_create_team",             default: true,  null: false
     t.string   "state"
-    t.integer  "color_scheme_id",            default: 1,     null: false
-    t.integer  "notification_level",         default: 1,     null: false
+    t.integer  "color_scheme_id",             default: 1,     null: false
+    t.integer  "notification_level",          default: 1,     null: false
     t.datetime "password_expires_at"
     t.integer  "created_by_id"
     t.datetime "last_credential_check_at"
@@ -833,23 +833,23 @@ ActiveRecord::Schema.define(version: 20151228175719) do
     t.datetime "confirmed_at"
     t.datetime "confirmation_sent_at"
     t.string   "unconfirmed_email"
-    t.boolean  "hide_no_ssh_key",            default: false
-    t.string   "website_url",                default: "",    null: false
+    t.boolean  "hide_no_ssh_key",             default: false
+    t.string   "website_url",                 default: "",    null: false
     t.string   "notification_email"
-    t.boolean  "hide_no_password",           default: false
-    t.boolean  "password_automatically_set", default: false
+    t.boolean  "hide_no_password",            default: false
+    t.boolean  "password_automatically_set",  default: false
     t.string   "location"
     t.string   "encrypted_otp_secret"
     t.string   "encrypted_otp_secret_iv"
     t.string   "encrypted_otp_secret_salt"
-    t.boolean  "otp_required_for_login",     default: false, null: false
+    t.boolean  "otp_required_for_login",      default: false, null: false
     t.text     "otp_backup_codes"
-    t.string   "public_email",               default: "",    null: false
-    t.integer  "dashboard",                  default: 0
-    t.integer  "project_view",               default: 0
+    t.string   "public_email",                default: "",    null: false
+    t.integer  "dashboard",                   default: 0
+    t.integer  "project_view",                default: 0
     t.integer  "consumed_timestep"
-    t.integer  "layout",                     default: 0
-    t.boolean  "hide_project_limit",         default: false
+    t.integer  "layout",                      default: 0
+    t.boolean  "hide_project_limit",          default: false
     t.string   "unlock_token"
     t.datetime "otp_grace_period_started_at"
   end