Merge branch 'hook-local-vars'

[sup] / lib / sup / mbox / ssh-file.rb

diff --git a/lib/sup/mbox/ssh-file.rb b/lib/sup/mbox/ssh-file.rb
index 7a61b72aa82aa36253b7315863a933c694cd9022..4ae4bbadf6f875b8655dbe5b461bca2b31afef22 100644 (file)
--- a/lib/sup/mbox/ssh-file.rb
+++ b/lib/sup/mbox/ssh-file.rb
@@ -16,12 +16,6 @@ class SSHFileError < StandardError; end
 ## all of the methods here can throw SSHFileErrors, SocketErrors,
 ## Net::SSH::Exceptions and Errno::ENOENTs.
 
-## debugging TODO: remove me
-def debug s
-  Redwood::log s
-end
-module_function :debug
-
 ## a simple buffer of contiguous data
 class Buffer
   def initialize
@@ -66,6 +60,7 @@ class Buffer
     x = @buf.index(what, start - @start)
     x.nil? ? nil : x + @start
   end
+
   def rindex what, start=0
     x = @buf.rindex(what, start - @start)
     x.nil? ? nil : x + @start
@@ -91,6 +86,12 @@ class SSHFile
   REASONABLE_TRANSFER_SIZE = 1024 * 32
   SIZE_CHECK_INTERVAL = 60 * 1 # seconds
 
+  ## upon these errors we'll try to rereconnect a few times
+  RECOVERABLE_ERRORS = [ Errno::EPIPE, Errno::ETIMEDOUT ]
+
+  @@shells = {}
+  @@shells_mutex = Mutex.new
+
   def initialize host, fn, ssh_opts={}
     @buf = Buffer.new
     @host = host
@@ -99,43 +100,15 @@ class SSHFile
     @file_size = nil
     @offset = 0
     @say_id = nil
-    @broken_msg = nil
     @shell = nil
-    @shell_mutex = Mutex.new
+    @shell_mutex = nil
+    @buf_mutex = Mutex.new
   end
 
-  def to_s; "mbox+ssh://#@host/#@fn"; end ## TODO: remove thisis EVILness
-  def broken?; !@broken_msg.nil?; end
-
-  ## TODO: share this code with imap
-  def say s
-    @say_id = BufferManager.say s, @say_id if BufferManager.instantiated?
-    Redwood::log s
-  end
-  def shutup
-    BufferManager.clear @say_id if BufferManager.instantiated?
-    @say_id = nil
-  end
-  private :say, :shutup
+  def to_s; "mbox+ssh://#@host/#@fn"; end ## TODO: remove this EVILness
 
   def connect
-    raise SSHFileError, @broken_msg if broken?
-
-    @shell_mutex.synchronize do
-      return if @shell
-
-      begin
-        say "Opening SSH connection to #{@host}..."
-        #raise SSHFileError, "simulated SSH file error"
-        session = Net::SSH.start @host, @ssh_opts
-        say "Starting SSH shell..."
-        @shell = session.shell.sync
-        say "Checking for #@fn..."
-        raise Errno::ENOENT, @fn unless @shell.test("-e #@fn").status == 0
-      ensure
-        shutup
-      end
-    end
+    do_remote nil
   end
 
   def eof?; @offset >= size; end
@@ -143,6 +116,7 @@ class SSHFile
   def seek loc; @offset = loc; end
   def tell; @offset; end
   def total; size; end
+  def path; @fn end
 
   def size
     if @file_size.nil? || (Time.now - @last_size_check) > SIZE_CHECK_INTERVAL
@@ -154,42 +128,81 @@ class SSHFile
 
   def gets
     return nil if eof?
-    make_buf_include @offset
-    expand_buf_forward while @buf.index("\n", @offset).nil? && @buf.endd < size
-    returning(@buf[@offset .. (@buf.index("\n", @offset) || -1)]) { |line| @offset += line.length }
+    @buf_mutex.synchronize do
+      make_buf_include @offset
+      expand_buf_forward while @buf.index("\n", @offset).nil? && @buf.endd < size
+      returning(@buf[@offset .. (@buf.index("\n", @offset) || -1)]) { |line| @offset += line.length }
+    end
   end
 
   def read n
     return nil if eof?
-    make_buf_include @offset, n
-    @buf[@offset ... (@offset += n)]
+    @buf_mutex.synchronize do
+      make_buf_include @offset, n
+      @buf[@offset ... (@offset += n)]
+    end
   end
 
 private
 
+  ## TODO: share this code with imap
+  def say s
+    @say_id = BufferManager.say s, @say_id if BufferManager.instantiated?
+    info s
+  end
+
+  def shutup
+    BufferManager.clear @say_id if BufferManager.instantiated? && @say_id
+    @say_id = nil
+  end
+
+  def unsafe_connect
+    return if @shell
+
+    @key = [@host, @ssh_opts[:username]]
+    begin
+      @shell, @shell_mutex = @@shells_mutex.synchronize do
+        unless @@shells.member? @key
+          say "Opening SSH connection to #{@host} for #@fn..."
+          session = Net::SSH.start @host, @ssh_opts
+          say "Starting SSH shell..."
+          @@shells[@key] = [session.shell.sync, Mutex.new]
+        end
+        @@shells[@key]
+      end
+      
+      say "Checking for #@fn..."
+      @shell_mutex.synchronize { raise Errno::ENOENT, @fn unless @shell.test("-e #@fn").status == 0 }
+    ensure
+      shutup
+    end
+  end
+
   def do_remote cmd, expected_size=0
+    retries = 0
+    result = nil
+
     begin
-      retries = 0
-      connect
-      # MBox::debug "sending command: #{cmd.inspect}"
-      begin
-        result = @shell.send_command cmd
+      unsafe_connect
+      if cmd
+        # MBox::debug "sending command: #{cmd.inspect}"
+        result = @shell_mutex.synchronize { x = @shell.send_command cmd; sleep 0.25; x }
         raise SSHFileError, "Failure during remote command #{cmd.inspect}: #{(result.stderr || result.stdout || "")[0 .. 100]}" unless result.status == 0
-      rescue Net::SSH::Exception # these happen occasionally for no apparent reason. gotta love that nondeterminism!
-        retry if (retries += 1) <= 3
-        raise
-      rescue Errno::EPIPE
-        if (retries += 1) <= e
+      end
+      ## Net::SSH::Exceptions seem to happen every once in a while for
+      ## no good reason.
+    rescue Net::SSH::Exception, *RECOVERABLE_ERRORS
+      if (retries += 1) <= 3
+        @@shells_mutex.synchronize do
           @shell = nil
-          connect
-          retry
+          @@shells[@key] = nil
         end
+        retry
       end
-    rescue Net::SSH::Exception, SSHFileError, Errno::ENOENT => e
-      @broken_msg = e.message
       raise
     end
-    result.stdout
+
+    result.stdout if cmd
   end
 
   def get_bytes offset, size