collect2, fetch2 tests

Gemfile

@@ -5,3 +5,5 @@ gem 'rack'
 gem 'puma'
 gem 'sd_notify'
 gem 'cbor'
+gem 'io-extra'
+gem 'ffi'

lib/lxc_collector.rb

@@ -3,6 +3,7 @@
 require 'pathname'
 require 'prometheus/client'
 require 'lxc'
+require 'ostruct'
 
 require_relative 'ns'
 require_relative 'file-statfs'
@@ -60,7 +61,7 @@ class LxcCollector
 
   AptLastUpdateFile = Pathname.new '/var/cache/apt/pkgcache.bin'
 
-  def forked wr
+  def forkedo wr
     LXC.running_containers do |ct|
       pid = ct.init_pid
       mis = MountInfo.of pid
@@ -106,7 +107,7 @@ class LxcCollector
     exit 0
   end
 
-  def collect
+  def collecto
     LXC.containers do |ct|
       labels = { id: ct.name, name: ct.config_item( 'lxc.uts.name') }
       @up.set ct.running? ? 1 : 0, labels: labels
@@ -147,9 +148,105 @@ class LxcCollector
     Process.wait pid
     @prometheus
   end
+
+  def forked2 io, ct
+    pid = ct.init_pid
+    mis = MountInfo.of pid
+    id, name = ct.name, ct.config_item( 'lxc.uts.name')
+    NS.enter pid, keep_open: [io, STDERR, STDOUT]
+
+    # Filesystems
+    statfs ct, mis do |ct, mp, st|
+      next  unless st.fstypename and 0 < st.blocks
+      st = st.to_h.merge mp: mp, id: id, name: name
+      io.write [:mountpoint, st]
+    end
+
+    # OS / Distribution
+    osr = OsRelease.read
+    unless osr.nil?
+      io.write [:os_release, {
+        id: id, name: name,
+        os_id:               osr[:id],
+        os_name:             osr[:name],
+        os_pretty_name:      osr[:pretty_name],
+        os_version_id:       osr[:version_id].to_i,
+        os_version_codename: osr[:version_codename]
+      }]
+
+      case osr[:id].to_sym
+      # Special things for Debian(-based) distributions
+      when :debian
+        upgradable = nil
+        pid = 
+          IO.popen %w[apt list --upgradable], err: "/dev/null" do |apt|
+            upgradable = apt.readlines.length - 1
+          end
+        io.write [:pkgs, {
+          id: id, name: name, upgradable: upgradable,
+          last_update: AptLastUpdateFile.stat.mtime.to_f,
+        }]
+      end
+    end
+  rescue Object
+    STDERR.puts "#{$!} (#{$!.class})", $!.backtrace.map {|x| "  #{x}"}
+  end
+
+  def collect2
+    LXC.containers do |ct|
+      labels = { id: ct.name, name: ct.config_item( 'lxc.uts.name') }
+      @up.set ct.running? ? 1 : 0, labels: labels
+      @state.set CTStates[ct.state], labels: labels
+    end
+
+    LXC.running_containers.map do |ct|
+      Thread.new ct do |ct|
+        pid, io = CBORIO.popen(:r) {|io| forked2 io, ct }
+        begin
+          io.map do |l|
+            case l[0].to_sym
+
+            when :mountpoint
+              st = OpenStruct.new l[1]
+              labels = { id: st.id, mountpoint: st.mp }
+              @info.set 1, labels: labels.merge( name: st.name, fstype: st.fstypename)
+              @totalb.set st.bsize*st.blocks, labels: labels
+              @freeb.set  st.bsize*st.bfree,  labels: labels
+              @availb.set st.bsize*st.bavail, labels: labels
+              @totalf.set st.files, labels: labels
+              @freef.set  st.ffree, labels: labels
+
+            when :os_release
+              osr = OpenStruct.new l[1]
+              @os_release.set 1, labels: {
+                id: osr.id, name: osr.name,
+                os_id: osr.os_id,
+                os_name: osr.os_name,
+                os_pretty_name: osr.os_pretty_name,
+                os_version_codename: osr.os_version_codename
+              }
+              @os_version.set osr.os_version_id, labels: { id: osr.id }
+
+            when :pkgs
+              as = OpenStruct.new l[1]
+              @pkgs_last_update.set as.last_update, labels: { id: as.id }
+              @pkgs_upgradable.set  as.upgradable,  labels: { id: as.id }
+            end
+          end
+        ensure
+          io.close
+          Process.wait pid
+        end
+      end
+    end.each &:join
+    @prometheus
+  end
+
+  alias forked forked2
+  alias collect collect2
 end
 
 if Pathname.new( __FILE__).expand_path == Pathname.new( $0).expand_path
   require 'prometheus/client/formats/text'
-  puts Prometheus::Client::Formats::Text.marshal( LxcCollector.new.collect)
+  puts Prometheus::Client::Formats::Text.marshal( LxcCollector.new.collect2)
 end

lib/ns.rb

@@ -1,5 +1,6 @@
 require 'fiddle'
 require 'fiddle/import'
+require 'io/extra'
 
 class NS
   extend Fiddle::Importer
@@ -32,30 +33,56 @@ class NS
         ns.change &exe
       end
     end
+
+    def enter pid, keep_open: nil
+      new( pid).enter keep_open: keep_open
+    end
   end
 
-  attr_reader :pid, :fds, :types
+  attr_reader :pid, :fds
 
   def initialize pid, *types
     @pid, @fds = pid, {}
-    types.map {|t| @fds[t] = self.class._open_nsfd pid, t }
+    types = Dir.children "/proc/%d/ns" % pid  if types.empty? or types.include?( :any)
+    types.each {|t| @fds[t.to_sym] = self.class._open_nsfd pid, t }
+  end
+
+  def close_ios *keep_open
+    keep_open =
+      keep_open.flatten.map do |fd|
+        case fd
+        when Integer then fd
+        when IO then fd.to_i
+        when nil # ignore
+        else raise ArgumentError, "Unknown file descriptor for keeping opened: #{fd.inspect}"
+        end
+      end.sort
+    IO.fdwalk(0) {|fd| fd.close  unless keep_open.include? fd.to_i }
+  end
+
+  def enter keep_open: nil
+    close_ios keep_open, @fds.values
+    @fds.each {|_, fd| self.class.setns fd, 0 }
+    close
+    nil
   end
 
   def close
-    @fds.each {|t, fd| fd.close }
+    @fds.each {|_, fd| fd.close }
   end
 
   def change &block
-    @owns = @fds.map {|t, _f| Own[t] }
+    if block_given?
+      @owns = @fds.map {|ns, _f| self.class._open_nsfd $$, ns }
       begin
         @fds.each {|type, fd| self.class.setns fd, 0 }
         yield
       ensure
         @owns.each {|fd| self.class.setns fd, 0 }
       end
+    else
+      @fds.each {|type, fd| self.class.setns fd, 0 }
+      nil
+    end
   end
-
-  Own = Hash.new {|h, ns| h[ns] = _open_nsfd $$, ns }
 end
-
-