Initial implementation of the hook feature

The current implementation is modular and allows users to define hooks
in several ways:
  * Use one of the built-in hook types (currently only 'exec')
  * Define their own Hook classes inside ~/.config/oxidized/hook

Exec hook type runs a user defined command with or without shell. It
populates a bunch of environment variables with metadata. The command
can either be run as synchronous or asynchronous. The default is
synchronous.

8 files changed, 204 insertions, 4 deletions

diff --git a/lib/oxidized/config.rb b/lib/oxidized/config.rb
index 96c8fbf..f45004a 100644
--- a/lib/oxidized/config.rb
+++ b/lib/oxidized/config.rb
@@ -9,10 +9,11 @@ module Oxidized
     OutputDir = File.join Directory, %w(lib oxidized output)
     ModelDir  = File.join Directory, %w(lib oxidized model)
     SourceDir = File.join Directory, %w(lib oxidized source)
+    HookDir   = File.join Directory, %w(lib oxidized hook)
     Sleep     = 1
   end
   class << self
-    attr_accessor :mgr
+    attr_accessor :mgr, :Hooks
   end
   CFGS = Asetus.new :name=>'oxidized', :load=>false, :key_to_s=>true
   CFGS.default.username      = 'username'
diff --git a/lib/oxidized/core.rb b/lib/oxidized/core.rb
index 71267dd..b70443c 100644
--- a/lib/oxidized/core.rb
+++ b/lib/oxidized/core.rb
@@ -6,6 +6,7 @@ module Oxidized
   require 'oxidized/worker'
   require 'oxidized/nodes'
   require 'oxidized/manager'
+  require 'oxidized/hook'
   class << self
     def new *args
       Core.new args
@@ -15,6 +16,7 @@ module Oxidized
   class Core
     def initialize args
       Oxidized.mgr = Manager.new
+      Oxidized.Hooks = HookManager.from_config CFG
       nodes        = Nodes.new
       @worker      = Worker.new nodes
       trap('HUP') { nodes.load }
diff --git a/lib/oxidized/hook.rb b/lib/oxidized/hook.rb
new file mode 100644
index 0000000..2763c4f
--- /dev/null
+++ b/lib/oxidized/hook.rb
@@ -0,0 +1,88 @@
+module Oxidized
+class HookManager
+  class << self
+    def from_config cfg
+      mgr = new
+      cfg.hooks.each do |name,h_cfg|
+        h_cfg.events.each do |event|
+          mgr.register event.to_sym, name, h_cfg.type, h_cfg
+        end
+      end
+      mgr
+    end
+  end
+
+  # HookContext is passed to each hook. It can contain anything related to the
+  # event in question. At least it contains the event name
+  class HookContext < OpenStruct; end
+
+  # RegisteredHook is a container for a Hook instance
+  class RegisteredHook < Struct.new(:name, :hook); end
+
+  Events = [ 
+    :node_success,
+    :node_fail,
+    :post_store,
+  ]
+  attr_reader :registered_hooks
+
+  def initialize
+    @registered_hooks = Hash.new {|h,k| h[k] = []}
+  end
+
+  def register event, name, hook_type, cfg
+    unless Events.include? event
+      raise ArgumentError,
+        "unknown event #{event}, available: #{Events.join ','}"
+    end
+
+    Oxidized.mgr.add_hook hook_type
+    begin
+      hook = Oxidized.mgr.hook.fetch(hook_type).new
+    rescue KeyError
+      raise KeyError, "cannot find hook #{hook_type.inspect}"
+    end
+
+    hook.cfg = cfg
+
+    @registered_hooks[event] << RegisteredHook.new(name, hook)
+    Log.debug "Hook #{name.inspect} registered #{hook.class} for event #{event.inspect}"
+  end
+
+  def handle event, **ctx_params
+    ctx = HookContext.new ctx_params
+    ctx.event = event
+
+    @registered_hooks[event].each do |r_hook|
+      begin
+        r_hook.hook.run_hook ctx
+      rescue => e
+        Log.error "Hook #{r_hook.name} (#{r_hook.hook}) failed " +
+                  "(#{e.inspect}) for event #{event.inspect}"
+      end
+    end
+  end
+end
+
+# Hook abstract base class
+class Hook
+  attr_accessor :cfg
+
+  def initialize
+  end
+
+  def cfg=(cfg)
+    @cfg = cfg
+    validate_cfg! if self.respond_to? :validate_cfg!
+  end
+
+  def run_hook ctx
+    raise NotImplementedError
+  end
+
+  def log(msg, level=:info)
+    Log.send(level, "#{self.class.name}: #{msg}")
+  end
+
+end
+end
diff --git a/lib/oxidized/hook/exec.rb b/lib/oxidized/hook/exec.rb
new file mode 100644
index 0000000..eb71466
--- /dev/null
+++ b/lib/oxidized/hook/exec.rb
@@ -0,0 +1,84 @@
+class Exec < Oxidized::Hook
+  include Process
+
+  def initialize
+    super
+    @timeout = 60
+    @async = false
+  end
+
+  def validate_cfg!
+    # Syntax check
+    if cfg.has_key? "timeout" 
+      @timeout = cfg.timeout
+      raise "invalid timeout value" unless @timeout.is_a?(Integer) && 
+                                           @timeout > 0
+    end
+
+    if cfg.has_key? "async"
+      @async = !!cfg.async
+    end
+
+    if cfg.has_key? "cmd"
+      @cmd = cfg.cmd
+      raise "invalid cmd value" unless @cmd.is_a?(String) || @cmd.is_a?(Array)
+    end
+
+  rescue RuntimeError => e
+    raise ArgumentError, 
+      "#{self.class.name}: configuration invalid: #{e.message}"
+  end
+
+  def run_hook ctx
+    env = make_env ctx
+    log "Execute: #{@cmd.inspect}", :debug
+    th = Thread.new do
+      begin
+        run_cmd! env
+      rescue => e
+        raise e unless @async
+      end
+    end
+    th.join unless @async
+  end
+
+  def run_cmd! env
+    pid, status = nil, nil
+    Timeout.timeout(@timeout) do
+      pid = spawn env, @cmd , :unsetenv_others => true
+      pid, status = wait2 pid
+      unless status.exitstatus.zero?
+        msg = "#{@cmd.inspect} failed with exit value #{status.exitstatus}"
+        log msg, :error
+        raise msg
+      end
+    end
+  rescue TimeoutError
+    kill "TERM", pid
+    msg = "#{@cmd} timed out"
+    log msg, :error
+    raise TimeoutError, msg
+  end
+
+  def make_env ctx
+    env = {
+      "OX_EVENT" => ctx.event.to_s
+    }
+    if ctx.node
+      env.merge!(
+        "OX_NODE_NAME" => ctx.node.name.to_s,
+        "OX_NODE_FROM" => ctx.node.from.to_s,
+        "OX_NODE_MSG" => ctx.node.msg.to_s,
+        "OX_NODE_GROUP" => ctx.node.group.to_s,
+        "OX_EVENT" => ctx.event.to_s,
+      )
+    end
+    if ctx.job
+      env.merge!(
+        "OX_JOB_STATUS" => ctx.job.status.to_s,
+        "OX_JOB_TIME" => ctx.job.time.to_s,
+      )
+    end
+    env
+  end
+end
diff --git a/lib/oxidized/hook/noophook.rb b/lib/oxidized/hook/noophook.rb
new file mode 100644
index 0000000..d4673ba
--- /dev/null
+++ b/lib/oxidized/hook/noophook.rb
@@ -0,0 +1,9 @@
+class NoopHook < Oxidized::Hook
+  def validate_cfg!
+    log "Validate config"
+  end
+
+  def run_hook ctx
+    log "Run hook with context: #{ctx}"
+  end
+end
diff --git a/lib/oxidized/manager.rb b/lib/oxidized/manager.rb
index b4eaecd..bf28ae7 100644
--- a/lib/oxidized/manager.rb
+++ b/lib/oxidized/manager.rb
@@ -23,12 +23,13 @@ module Oxidized
         end
       end
     end
-    attr_reader :input, :output, :model, :source
+    attr_reader :input, :output, :model, :source, :hook
     def initialize
       @input  = {}
       @output = {}
       @model  = {}
       @source = {}
+      @hook = {}
     end
     def add_input method
       method = Manager.load Config::InputDir, method
@@ -53,5 +54,13 @@ module Oxidized
       return false if _source.empty?
       @source.merge! _source
     end
+    def add_hook _hook
+      return nil if @hook.key? _hook
+      name = _hook
+      _hook = Manager.load File.join(Config::Root, 'hook'), name
+      _hook = Manager.load Config::HookDir, name if _hook.empty?
+      return false if _hook.empty?
+      @hook.merge! _hook
+    end
   end
 end
diff --git a/lib/oxidized/worker.rb b/lib/oxidized/worker.rb
index 6bb2a22..eea747e 100644
--- a/lib/oxidized/worker.rb
+++ b/lib/oxidized/worker.rb
@@ -34,12 +34,16 @@ module Oxidized
       @jobs.duration job.time
       node.running = false
       if job.status == :success
+        Oxidized.Hooks.handle :node_success, :node => node,
+                                             :job => job
         msg = "update #{node.name}"
         msg += " from #{node.from}" if node.from
         msg += " with message '#{node.msg}'" if node.msg
         if node.output.new.store node.name, job.config,
                               :msg => msg, :user => node.user, :group => node.group
           Log.info "Configuration updated for #{node.group}/#{node.name}"
+          Oxidized.Hooks.handle :post_store, :node => node,
+                                             :job => job
         end
         node.reset
       else
@@ -51,6 +55,8 @@ module Oxidized
         else
           msg += ", retries exhausted, giving up"
           node.retry = 0
+          Oxidized.Hooks.handle :node_fail, :node => node,
+                                            :job => job
         end
         Log.warn msg
       end
diff --git a/oxidized.gemspec b/oxidized.gemspec
index ae069cf..4ad6e92 100644
--- a/oxidized.gemspec
+++ b/oxidized.gemspec
@@ -3,8 +3,8 @@ Gem::Specification.new do |s|
   s.version           = '0.7.2'
   s.licenses          = %w( Apache-2.0 )
   s.platform          = Gem::Platform::RUBY
-  s.authors           = [ 'Saku Ytti', 'Samer Abdel-Hafez' ]
-  s.email             = %w( saku@ytti.fi sam@arahant.net )
+  s.authors           = [ 'Saku Ytti', 'Samer Abdel-Hafez', 'Anton Aksola' ]
+  s.email             = %w( saku@ytti.fi sam@arahant.net aakso@iki.fi)
   s.homepage          = 'http://github.com/ytti/oxidized'
   s.summary           = 'feeble attempt at rancid'
   s.description       = 'software to fetch configuration from network devices and store them'
@@ -18,4 +18,5 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'slop',    '~> 3.5'
   s.add_runtime_dependency 'net-ssh', '~> 2.8'
   s.add_runtime_dependency 'rugged',  '~> 0.21', '>= 0.21.4'
+  s.add_development_dependency 'pry'
 end