ProcessWrapperMessageProtocol modified by Ben Sawyer

Ben Sawyer — Wed, 14 May 2014 03:07:32 -0000

--- v1
+++ v2
@@ -19,8 +19,9 @@
 STILL_ALIVE | 0x03       | Keep alive acknowledgement
 LINE        | 0x10       | A line of output from the wrapper, or a line of input from the daemon
 ERROR       | 0xA0       | Reports an error
-STOP        | 0xE0       | Instructs wrapper to stop process
-KILL        | 0xE1       | Instructs wrapper to kill process
+START       | 0xE0       | Instructs wrapper to start process
+STOP        | 0xE1       | Instructs wrapper to stop process
+KILL        | 0xE2       | Instructs wrapper to kill process
 EXIT        | 0xFF       | Instructs wrapper to exit

@@ -32,16 +33,17 @@

 Key       | Value                
 ----------|----------------------
+txId      | Transaction ID for this request
 protoVer  | The protocol version being used
-pid       | The PID of the wrapper process
+clientId  | The PID of the wrapper process

 #### ACK ####

-Acknowledges successful receipt/execution of a message.
+Acknowledges successful receipt/execution of a message.  Ack messages have varying properties depending on the type of message that is being acknowledged.

 Key       | Value                
 ----------|----------------------
-mid       | The ID of the message this message is acknowledging
+txId      | ID of the transaction this message is acknowledging

 #### KEEP_ALIVE ####

@@ -58,6 +60,7 @@
 Key       | Value                
 ----------|----------------------
 l         | The line of input/output
+txId      | The transaction ID for this request (Daemon to Wrapper only)

 #### ERROR ####

@@ -65,19 +68,94 @@

 Key       | Value                
 ----------|----------------------
-mid       | The ID of the message that requested the operation that resulted in an error (absent if error was not the result of an action requested by a message)
+txId      | The ID of the request that resulted in an error (absent if error was not the result of an action requested by a message)
 code      | The error code
-message   | (optional) The error message, if there is one
+exitCode  | (optional) The Process' exit code, if there was

 #### STOP ####

-Stop messages have no K/V pairs.
+Key       | Value                
+----------|----------------------
+txId      | Transaction ID for this request

 #### KILL ####

-Kill messages have no K/V pairs
+Key       | Value                
+----------|----------------------
+txId      | Transaction ID for this request

+#### EXIT ####
+
+Key       | Value                
+----------|----------------------
+txId      | Transaction ID for this request

 ### Message Exchanges ###

+D>W and D<-W      | INIT        | Start handshake
+2a       | D->W      | ACK         | Handshake successful
+2b       | D->W      | EXIT        | Sent as response if error such as protocol mismatch is encountered
+
+#### INIT Reconnect ####
+
+Sent if daemon restarts to re-establish connection with wrapper
+
+Sequence | Direction | Message/Key | Description/Value
+---------|-----------|-------------|-----------------------
+1        | D->W      | INIT        |
+2        | D<-W      | ACK         | 
+
+#### START Pprocess ####
+
+Instructs wrapper to start the designated process, and establish a connection to the process' IO channels.
+
+Sequence | Direction | Message/Key | Description/Value
+---------|-----------|-------------|-----------------------
+1        | D->W      | START       |
+2        | D<-W      | ACK         | Acknowledge message received
+3a       | D<-W      | ACK         | Acknowledge process started successfully
+3b       | D<-W      | ERROR       | If process did not start successfully
+
+#### STOP Process ####
+
+Instructs wrapper to send SIGTERM the running process
+
+Sequence | Direction | Message/Key | Description/Value
+---------|-----------|-------------|-----------------------
+1        | D->W      | STOP        |
+2a       | D<-W      | ACK         | Acknowledge message received
+2b       | D<-W      | ERROR       | Sent if process is not running
+3a       | D<-W      | ACK         | Acknowledge process stopped successfully
+         |           |    exitCode | The process' exit code
+3c       | D<-W      | ERROR       | Sent if process did not respond to stop message
+
+#### LINE From Wrapper ####
+
+This will be the most common transaction type.  We do not need guaranteed delivery for these messages, so the daemon does not sent an ACK response
+
+Sequence | Direction | Message/Key | Description/Value
+---------|-----------|-------------|-----------------------
+1        | D<-W      | LINE        | 
+
+#### LINE From Daemon ####
+
+We need to ensure that commands we are trying to send to the process are getting executed, so an ACK is required
+
+Sequence | Direction | Message/Key | Description/Value
+---------|-----------|-------------|-----------------------
+1        | D->W      | LINE        |
+2        | D<-W      | ACK         |
+
+
+
+
+
 Work in progress...

ProcessWrapperMessageProtocol modified by Ben Sawyer

Ben Sawyer — Sat, 10 May 2014 01:21:16 -0000

Overview
Type/Word Bytes
- List of Valid Word Bytes
Message Structures
- INIT
- ACK
- KEEP_ALIVE
- STILL_ALIVE
- LINE
- ERROR
- STOP
- KILL
Message Exchanges

Overview

This article outlines the protocol for messages exchanged between the daemon and process wrapper.

Type/Word Bytes

Each message contains a message type or "word" byte. This byte defines what type of message follows, and can be used to determine how to handle or respond to a message.

List of Valid Word Bytes

Enum Name	Byte Value	Meaning
INIT	0x00	Used to initialize the connection between daemon and wrapper
ACK	0x01	Standard acknowledgement of message receipt/execution
KEEP_ALIVE	0x02	Standard keep alive message
STILL_ALIVE	0x03	Keep alive acknowledgement
LINE	0x10	A line of output from the wrapper, or a line of input from the daemon
ERROR	0xA0	Reports an error
STOP	0xE0	Instructs wrapper to stop process
KILL	0xE1	Instructs wrapper to kill process
EXIT	0xFF	Instructs wrapper to exit

Message Structures

INIT

Initializes the connection between the daemon and wrapper.

Key	Value
protoVer	The protocol version being used
pid	The PID of the wrapper process

ACK

Acknowledges successful receipt/execution of a message.

Key	Value
mid	The ID of the message this message is acknowledging

KEEP_ALIVE

Keep alive messages have no K/V pairs.

STILL_ALIVE

Still alive messages have no K/V pairs.

LINE

Line messages contain a single K/V pair containing the line of output being delivered from the process to the daemon, or the line of input to be sent to the process from the daemon

Key	Value
l	The line of input/output

ERROR

Reports an error

Key	Value
mid	The ID of the message that requested the operation that resulted in an error (absent if error was not the result of an action requested by a message)
code	The error code
message	(optional) The error message, if there is one

STOP

Stop messages have no K/V pairs.

KILL

Kill messages have no K/V pairs

Message Exchanges

Work in progress...

Recent changes to ProcessWrapperMessageProtocol

ProcessWrapperMessageProtocol modified by Ben Sawyer

ProcessWrapperMessageProtocol modified by Ben Sawyer

Overview

Type/Word Bytes

List of Valid Word Bytes

Message Structures

INIT

ACK

KEEP_ALIVE

STILL_ALIVE

LINE

ERROR

STOP

KILL

Message Exchanges