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
def to_s; empty? ? "<empty>" : "[#{start}, #{endd})"; end # for debugging
end
+## sharing a ssh connection to one machines between sources seems to
+## create lots of broken situations: commands returning bizarre (large
+## positive integer) return codes despite working; commands
+## occasionally not working, etc. i suspect this is because of the
+## fragile nature of the ssh syncshell.
+##
+## at any rate, we now open up one ssh connection per file, which is
+## probably silly in the extreme case.
+
## the file-like interface to a remote file
class SSHFile
MAX_BUF_SIZE = 1024 * 1024 # bytes
- MAX_TRANSFER_SIZE = 1024 * 64
+ MAX_TRANSFER_SIZE = 1024 * 128
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
@file_size = nil
@offset = 0
@say_id = nil
- @broken_msg = nil
+ @shell = nil
+ @shell_mutex = nil
+ @buf_mutex = Mutex.new
end
- def broken?; !@broken_msg.nil?; end
-
- def say s
- @say_id = BufferManager.say s, @say_id if BufferManager.instantiated?
- Redwood::log s
- end
- private :say
-
- def shutup
- BufferManager.clear @say_id if BufferManager.instantiated?
- @say_id = nil
- end
+ def to_s; "mbox+ssh://#@host/#@fn"; end ## TODO: remove this EVILness
def connect
- return if @session
- raise SSHFileError, @broken_msg if broken?
-
- say "Opening SSH connection to #{@host}..."
-
- begin
- #raise SSHFileError, "simulated SSH file error"
- #@session = Net::SSH.start @host, @ssh_opts
- sleep 3
- say "Starting SSH shell..."
- # @shell = @session.shell.sync
- sleep 3
- say "Checking for #@fn..."
- sleep 1
- raise Errno::ENOENT, @fn
- raise Errno::ENOENT, @fn unless @shell.test("-e #@fn").status == 0
- ensure
- shutup
- end
+ do_remote nil
end
def eof?; @offset >= size; end
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
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?
+ Redwood::log 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
- raise SSHFileError, "Failure during remote command #{cmd.inspect}: #{result.stderr[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
+ 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
+ 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
+ @@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
projects / sup / blobdiff