add serf reporter by https://github.com/patrickviet

README.md

@@ -85,6 +85,23 @@ If you set your `reporter_type` to `"etcd"` you should also set these parameters
 * `etcd_port`: port to connect to etcd.
 * `etcd_path`: the path where the registration will be created; nerve will create a node with a 30s ttl that is the registration as a child of this path, and then update it every few seconds
 
+#### Serf Reporter ####
+
+You can use Nerve together with [Serf](https://www.serf.io/), which requires:
+
+* a Serf agent running on the same machine as Nerve
+* Setting your `reporter_type` to `"serf"` 
+* `serf_config_dir`: a directory to place files in that is readable/writable by both Serf and Nerve. 
+    * Nerve will place configuration files named `zzz_nerve_<some-service>_<port>.json` under the directory specified with `serf_config_dir`. 
+    * Serf will read these configurations and must be configured to run with `-config-dir=<serf_config_dir>`
+    * Please note that it is up to you (through e.g. configuration management code) to ensure no invalid configuration files are left under `serf_config_dir` by wiping all `zzz_nerve*` files when renaming/removing services. (each nerve reporter creates/deletes files for services named `<service-name>`, but renaming `<service-name>`  to `<service-name2>` on an existing machine could lead to stale configuration files remaining under `serf_config_dir`).
+* Nerve must have permissions to reload the serf process. (can be specified by the `serf_reload_command` parameter - defaults to `/usr/bin/killall -HUP serf`)
+    * (You can for example install Serf and Nerve to run under the same user) 
+
+Configuration management code and example Vagrant setup to use Serf together with Nerve/Synapse can be found here:
+
+* Ansible: https://github.com/AutomationWithAnsible/ansible-smartstack
+
 ### Checks ###
 
 The core of nerve is a set of service checks.

example/nerve_services/serf_service1.json

@@ -0,0 +1,16 @@
+{
+  "host": "1.2.3.4",
+  "port": 3000,
+  "reporter_type": "serf",
+  "check_interval": 2,
+  "weight": 2,
+  "checks": [
+    {
+      "type": "http",
+      "uri": "/health",
+      "timeout": 0.2,
+      "rise": 3,
+      "fall": 2
+    }
+  ]
+}

lib/nerve/reporter/serf.rb

@@ -0,0 +1,51 @@
+require 'nerve/reporter/base'
+
+class Nerve::Reporter
+  class Serf < Base
+    def initialize(service)
+
+      # Set default parameters - the defaults are sane so nothing needed.
+      @config_dir = service['serf_config_dir'] || '/etc/serf'
+      @reload_command = service['serf_reload_command'] || '/usr/bin/killall -HUP serf'
+      @name       = service['name']
+      # please note that because of
+      # https://github.com/airbnb/smartstack-cookbook/blob/master/recipes/nerve.rb#L71
+      # the name won't just be the name you gave but name_port. this allows a same
+      # service to be on multiple ports of a same machine.
+
+      @data = parse_data(get_service_data(service))
+      @config_file = File.join(@config_dir,"zzz_nerve_#{@name}.json")
+      File.unlink @config_file if File.exists? @config_file
+    end
+
+    def start()
+      log.info "nerve: started to maintain the tag #{@name} with Serf"
+    end
+
+    def report_up()
+      update_data(false)
+    end
+
+    def report_down
+      File.unlink(@config_file)
+      reload_serf
+    end
+
+    def update_data(new_data='')
+      @data = new_data if new_data
+      data = JSON.parse(@data)
+      tag = "#{data['host']}:#{data['port']}"
+      File.write(@config_file, JSON.generate({tags:{"smart:#{@name}" =>tag}}))
+      reload_serf
+    end
+
+    def reload_serf()
+      system(@reload_command)
+    end
+
+    def ping?
+      # for now return true.
+      return true
+    end
+  end
+end

spec/configuration_manager_spec.rb

@@ -24,7 +24,7 @@
       expect(config_manager.config.keys()).to include('instance_id', 'services')
       expect(config_manager.config['services'].keys()).to contain_exactly(
         'your_http_service', 'your_tcp_service', 'rabbitmq_service',
-        'etcd_service1', 'zookeeper_service1'
+        'etcd_service1', 'serf_service1',  'zookeeper_service1'
       )
     end
   end