From 4c1cd629aeef612b2487026d1643141830ba7c08 Mon Sep 17 00:00:00 2001 From: Ryan Breen Date: Tue, 3 Feb 2015 17:07:03 -0500 Subject: [PATCH 1/2] Cleanup docs/agent/rpc --- website/source/docs/agent/rpc.html.markdown | 68 +++++++++++---------- 1 file changed, 35 insertions(+), 33 deletions(-) diff --git a/website/source/docs/agent/rpc.html.markdown b/website/source/docs/agent/rpc.html.markdown index 1a760509f1..8fec3a2ed4 100644 --- a/website/source/docs/agent/rpc.html.markdown +++ b/website/source/docs/agent/rpc.html.markdown @@ -3,23 +3,24 @@ layout: "docs" page_title: "RPC" sidebar_current: "docs-agent-rpc" description: |- - The Consul agent provides a complete RPC mechanism that can be used to control the agent programmatically. This RPC mechanism is the same one used by the CLI, but can be used by other applications to easily leverage the power of Consul without directly embedding. + The Consul agent provides a complete RPC mechanism that can be used to control the agent programmatically. This RPC mechanism is the same one used by the CLI but can be used by other applications to easily leverage the power of Consul without directly embedding. --- # RPC Protocol The Consul agent provides a complete RPC mechanism that can be used to control the agent programmatically. This RPC -mechanism is the same one used by the CLI, but can be +mechanism is the same one used by the CLI but can be used by other applications to easily leverage the power -of Consul without directly embedding. It is important to note -that the RPC protocol does not support all the same operations -as the [HTTP API](/docs/agent/http.html). +of Consul without directly embedding. + +It is important to note that the RPC protocol does not support +all the same operations as the [HTTP API](/docs/agent/http.html). ## Implementation Details The RPC protocol is implemented using [MsgPack](http://msgpack.org/) -over TCP. This choice is driven by the fact that all operating +over TCP. This choice was driven by the fact that all operating systems support TCP, and MsgPack provides a fast serialization format that is broadly available across languages. @@ -43,35 +44,35 @@ a response body. The response header looks like: } ``` -The `Command` is used to specify what command the server should +The `Command` in the quest is used to specify what command the server should run, and the `Seq` is used to track the request. Responses are tagged with the same `Seq` as the request. This allows for some -concurrency on the server side, as requests are not purely FIFO. +concurrency on the server side as requests are not purely FIFO. Thus, the `Seq` value should not be re-used between commands. All responses may be accompanied by an error. Possible commands include: -* handshake - Used to initialize the connection, set the version +* handshake - Initializes the connection and set the version * force-leave - Removes a failed node from the cluster * join - Requests Consul join another node * members-lan - Returns the list of LAN members * members-wan - Returns the list of WAN members * monitor - Starts streaming logs over the connection * stop - Stops streaming logs -* leave - Consul agent performs a graceful leave and shutdown +* leave - Instructs Consul agent to perform a graceful leave and shutdown * stats - Provides various debugging statistics * reload - Triggers a configuration reload -Below each command is documented along with any request or +Each command is documented below along with any request or response body that is applicable. ### handshake -The handshake MUST be the first command that is sent, as it informs +The handshake MUST be the first command that is sent as it informs the server which version the client is using. -The request header must be followed with a handshake body, like: +The request header must be followed by a handshake body, like: ```javascript { @@ -79,7 +80,7 @@ The request header must be followed with a handshake body, like: } ``` -The body specifies the IPC version being used, however only version +The body specifies the IPC version being used; however, only version 1 is currently supported. This is to ensure backwards compatibility in the future. @@ -101,7 +102,7 @@ There is no special response body. ### join -This command is used to join an existing cluster using a known node. +This command is used to join an existing cluster using one or more known nodes. It takes the following body: ```javascript @@ -115,13 +116,13 @@ It takes the following body: ``` The `Existing` nodes are each contacted, and `WAN` controls if we are adding a -WAN member or LAN member. LAN members are expected to be in the same datacenter, +WAN member or LAN member. LAN members are expected to be in the same datacenter and should be accessible at relatively low latencies. WAN members are expected to -be operating in different datacenters, with relatively high access latencies. It is +be operating in different datacenters with relatively high access latencies. It is important that only agents running in "server" mode are able to join nodes over the WAN. -The response body in addition to the header is returned. The body looks like: +The response contains both a header and body. The body looks like: ```javascript { @@ -129,11 +130,11 @@ The response body in addition to the header is returned. The body looks like: } ``` -The body returns the number of nodes successfully joined. +'Num' indicates the number of nodes successfully joined. ### members-lan -The members-lan command is used to return all the known LAN members and associated +This command is used to return all the known LAN members and associated information. All agents will respond to this command. There is no request body, but the response looks like: @@ -163,7 +164,7 @@ There is no request body, but the response looks like: ### members-wan -The members-wan command is used to return all the known WAN members and associated +This command is used to return all the known WAN members and associated information. Only agents in server mode will respond to this command. There is no request body, and the response is the same as `members-lan` @@ -172,7 +173,7 @@ There is no request body, and the response is the same as `members-lan` The monitor command subscribes the channel to log messages from the Agent. -The request is like: +The request looks like: ```javascript { @@ -183,8 +184,8 @@ The request is like: This subscribes the client to all messages of at least DEBUG level. The server will respond with a standard response header indicating if the monitor -was successful. However, now as logs occur they will be sent and tagged with -the same `Seq` as the monitor command that matches. +was successful. If so, any future logs will be sent and tagged with +the same `Seq` as in the `monitor` request. Assume we issued the previous monitor command with Seq `50`, we may start getting messages like: @@ -200,8 +201,8 @@ we may start getting messages like: } ``` -It is important to realize that these messages are sent asynchronously, -and not in response to any command. That means if a client is streaming +It is important to realize that these messages are sent asynchronously +and not in response to any command. If a client is streaming commands, there may be logs streamed while a client is waiting for a response to a command. This is why the `Seq` must be used to pair requests with their corresponding responses. @@ -211,7 +212,8 @@ To stop streaming, the `stop` command is used. ### stop -The stop command is used to stop a monitor. +This command stops a monitor. + The request looks like: ```javascript @@ -222,17 +224,17 @@ The request looks like: This unsubscribes the client from the monitor with `Seq` value of 50. -There is no special response body. +There is no response body. ### leave -The leave command is used trigger a graceful leave and shutdown. -There is no request body, or special response body. +This command is used trigger a graceful leave and shutdown. +There is no request body or special response body. ### stats -The stats command is used to provide operator information for debugging. -There is no request body, the response body looks like: +This command provides debug information. There is no request body, and the +response body looks like: ```javascript { @@ -250,5 +252,5 @@ There is no request body, the response body looks like: ### reload -The reload command is used trigger a reload of configurations. +This command is used trigger a reload of configurations. There is no request body, or special response body. From 8975c49c96a24a94f2e9f5ef70d996227b40d3df Mon Sep 17 00:00:00 2001 From: Ryan Breen Date: Tue, 3 Feb 2015 17:20:50 -0500 Subject: [PATCH 2/2] Cleanup docs/agent/rpc --- website/source/docs/agent/rpc.html.markdown | 23 +++++++++++---------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/website/source/docs/agent/rpc.html.markdown b/website/source/docs/agent/rpc.html.markdown index 8fec3a2ed4..272a4a96a5 100644 --- a/website/source/docs/agent/rpc.html.markdown +++ b/website/source/docs/agent/rpc.html.markdown @@ -44,7 +44,7 @@ a response body. The response header looks like: } ``` -The `Command` in the quest is used to specify what command the server should +The `Command` in the request is used to specify what command the server should run, and the `Seq` is used to track the request. Responses are tagged with the same `Seq` as the request. This allows for some concurrency on the server side as requests are not purely FIFO. @@ -53,14 +53,14 @@ All responses may be accompanied by an error. Possible commands include: -* handshake - Initializes the connection and set the version +* handshake - Initializes the connection and sets the version * force-leave - Removes a failed node from the cluster * join - Requests Consul join another node * members-lan - Returns the list of LAN members * members-wan - Returns the list of WAN members * monitor - Starts streaming logs over the connection * stop - Stops streaming logs -* leave - Instructs Consul agent to perform a graceful leave and shutdown +* leave - Instructs the Consul agent to perform a graceful leave and shutdown * stats - Provides various debugging statistics * reload - Triggers a configuration reload @@ -69,8 +69,9 @@ response body that is applicable. ### handshake -The handshake MUST be the first command that is sent as it informs -the server which version the client is using. +This command is used to initialize an RPC connection. As it informs +the server which version the client is using, handshake MUST be the +first command sent. The request header must be followed by a handshake body, like: @@ -187,8 +188,8 @@ The server will respond with a standard response header indicating if the monito was successful. If so, any future logs will be sent and tagged with the same `Seq` as in the `monitor` request. -Assume we issued the previous monitor command with Seq `50`, -we may start getting messages like: +Assume we issued the previous monitor command with `"Seq": 50`. We may start +getting messages like: ```javascript { @@ -228,8 +229,8 @@ There is no response body. ### leave -This command is used trigger a graceful leave and shutdown. -There is no request body or special response body. +This command is used to trigger a graceful leave and shutdown. +There is no request body or response body. ### stats @@ -252,5 +253,5 @@ response body looks like: ### reload -This command is used trigger a reload of configurations. -There is no request body, or special response body. +This command is used to trigger a reload of configurations. +There is no request body or response body.