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.

2 files changed, 93 insertions, 0 deletions

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