Refactor GoVPP

Squashed commit of the following:

commit 348930db31575e9f59b3834d9fec07411f011e05
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:30:13 2018 +0200

    Use debug level for log about different context

commit 9fc963c559cea67a41b85c6cdadc322fb3b1fc7c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:22:03 2018 +0200

    Remove annoying logs and add env vars for debugging

commit fdc9fd624d13feadb602e0d03d58f8a44b7a565f
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 15 11:18:47 2018 +0200

    Fix printing unknown VPPApiError

commit 8f968be36a91de4d4a8ea17593ba314f82aa9583
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Tue Aug 14 17:25:10 2018 +0200

    Refactor entire GoVPP

    - fix some cases with inconsistent VPP messages, causing messages
      to be incorrectly identified as event or request
    - simplify API, remove direct access to internal Go channels
    - add module name with message to registration of messages
    - start watching filesystem only when vpe-api file does not exist
    - simplify code in message codec and remove unneeded parts
    - retrieve IDs of all registered messages after connect to VPP
    - define fallback for control ping in core to avoid duplicate registration
    - add SetLogLevel function to set logger level more easily
    - remove lot of unused code

commit 34dd1b7e10ef0324aa8c4e4cc42375bd6021c6cb
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 11:29:54 2018 +0200

    Rename VnetError to VPPApiError

commit c6549d6f77847a1367a12ff47fb716e2955e973a
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 10:23:43 2018 +0200

    Fix examples and regenerate binapi

commit 4612e36b416779771f5efab4fc654c2766d2cb1c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Mon Aug 13 09:51:22 2018 +0200

    Add parsing and generation for services

commit ac9c5280c5aa27e325f327609e2364cc66f3723f
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Fri Aug 10 14:30:15 2018 +0200

    Fix exit status on error and add continue-onerror flag

commit 9b3f4ef9fc7c8c62037fa107085eae18a8725314
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 15:20:56 2018 +0200

    Return VnetError when Retval != 0

commit 8fd21a907b5e628ec4d2026215b83d15da96c297
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 14:59:05 2018 +0200

    Add all missing errors from api_errno.h

commit 08450f288d3046ebaecf40203174ae342a07f1eb
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 14:29:27 2018 +0200

    Update README

commit d8dced0728dd62243539be741868fb7d9b8de4cc
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:59:59 2018 +0200

    Regenerate vpe in core

commit 254da7592cdbf634cf7aa46ae36ce7bb6d4ee555
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:37:00 2018 +0200

    Add VnetError type for Retvals

commit 4475c1087fb53ab4c788e530bc7fef7cfc89d2cd
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:36:07 2018 +0200

    Add registration API

commit 892a3ea5a2c703e2f7c29331663f6a6fa706bff5
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 13:30:43 2018 +0200

    Generate registration for messages and check all IDs on connect

commit 389ed03b6e7082260281866c3449d72d72347c99
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:32:41 2018 +0200

    Show error for empty adapter (on Darwin/Windows)

commit ef1ea040d656ade64242432dc5f06810ed8dcde6
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:31:37 2018 +0200

    Improve logged info

commit d4adae3b14ed54c8d693060dd857fa9ba5ec8e06
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:27:48 2018 +0200

    Update examples

commit 63921e1346014701a22639a2611129563bb1eb78
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Thu Aug 9 11:02:56 2018 +0200

    Generate unions and fix some issues

    - add comments between sections
    - define structs on single line if it has no fields
    - generate unions with setters/getters for each field
    - fix detection of message type

commit 6ab3e3fa590b245898306a6ffaf32c7721eab60c
Author: Ondrej Fabry <ofabry@cisco.com>
Date:   Wed Aug 8 15:37:10 2018 +0200

    Refactor binapi-generator

    - split JSON parsing from code generation
    - parse and generate enums
    - parse unions (no generation yet)
    - change output file suffix to '.ba.go'
    - cleanup and simplify code
    - split code into files
    - add flag for debug mode

Change-Id: I58f685e0d4c7a38e9a7b6ea0a1f47792d95d7399
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

1 files changed, 41 insertions, 40 deletions

diff --git a/README.md b/README.md
index a5088f6..f1c83c6 100644
--- a/README.md
+++ b/README.md
@@ -1,53 +1,61 @@
-## GoVPP
-
-This set of packages provide the API for communication with VPP from Go. It consists of the following packages:
-
-- [govpp](govpp.go): provides the entry point to govpp functionality
-- [api](api/api.go): API for communication with govpp core using Go channels (without the need of importing the govpp core package itself),
-- [core](core/): main functionality of the govpp, sends and receives the messages to/from VPP using the adapter, marshalls/unmarshalls them and forwards them between the client Go channels and the VPP,
-- [adapter](adapter/): adapter between govpp core and the VPP, responsible for sending and receiving binary-encoded data via shared memory,
-- [binapi-generator](cmd/binapi-generator/generator.go): Generator of Go structs out of the VPP binary API definitions in JSON format,
-- [examples](examples/): example VPP management application that exercises the govpp API on real-world use-cases.
-
-The design with separated govpp API package ([api](api/api.go)) and the govpp core package ([core](core/)) enables 
-plugin-based infrastructure, where one entity acts as a master responsible for talking with VPP (e.g. Agent 
-Core on the schema below) and multiple entities act as clients that are using the master for the communication with 
-VPP (Agent Plugins on the schema below). The clients can be built into standalone shared libraries without the need 
-of linking the govpp core and all its dependencies into them.
+# GoVPP
+
+This set of packages provide the API for communication with VPP from Go. 
+
+It consists of the following packages:
+- [adapter](adapter/): adapter between GoVPP core and the VPP
+- [api](api/api.go): API for communication with GoVPP core
+- [binapi-generator](cmd/binapi-generator/): Generator for the VPP binary API definitions in JSON format to Go code
+- [codec](codec/): handles encoding/decoding of generated messages into binary form
+- [core](core/): main functionality of the GoVPP
+- [examples](examples/): examples that use the GoVPP API in real use-cases of VPP management application
+- [extras](extras/): contains Go implementation for libmemif library
+- [govpp](govpp.go): provides the entry point to GoVPP functionality
+
+The design with separated GoVPP [API package](api/api.go) and the GoVPP [core package](core/) enables 
+plugin-based infrastructure, where one entity acts as a master responsible for talking with VPP and multiple 
+entities act as clients that are using the master for the communication with VPP. 
+The clients can be built into standalone shared libraries without the need 
+of linking the GoVPP core and all its dependencies into them.
 
 ```
                                        +--------------+
     +--------------+                   |              |
-    |              |                   | Agent Plugin |
+    |              |                   |  App plugin  |
     |              |                   |              |
-    |  Agent Core  |                   +--------------+
-    |              |            +------+  govpp API   |
+    |     App      |                   +--------------+
+    |              |            +------+  GoVPP API   |
     |              |            |      +--------------+
     +--------------+     Go     |
     |              |  channels  |      +--------------+
-    |  govpp core  +------------+      |              |
-    |              |            |      | Agent Plugin |
+    |  GoVPP core  +------------+      |              |
+    |              |            |      |  App plugin  |
     +------+-------+            |      |              |
            |                    |      +--------------+
-binary API |                    +------+  govpp API   |
-  (shmem)  |                           +--------------+
+binary API |                    +------+  GoVPP API   |
+ (shmem)   |                           +--------------+
            |
     +------+-------+
     |              |
-    |      VPP     |    
+    |  VPP process |    
     |              |
     +--------------+
 ```
 
+## Quick Start
+
+#### Code Generator
 
-## Example usage
 Generating Go bindings from the JSON files located in the `/usr/share/vpp/api/` directory 
 into the Go packages that will be created inside of the `bin_api` directory:
 ```
 binapi-generator --input-dir=/usr/share/vpp/api/ --output-dir=bin_api
 ```
 
+#### Example Usage
+
 Usage of the generated bindings:
+
 ```go
 func main() {
 	conn, _ := govpp.Connect()
@@ -87,13 +95,14 @@ func main() {
 The example above uses simple wrapper API over underlying go channels, see [example client](examples/cmd/simple-client/simple_client.go) 
 for more examples, including the example on how to use the Go channels directly.
 
-
 ## Build & Installation Procedure
-Govpp uses `vppapiclient` library from VPP codebase to communicate with VPP. To build govpp, vpp-dev package must be installed,
+
+Govpp uses `vppapiclient` library from VPP codebase to communicate with VPP. To build GoVPP, vpp-dev package must be installed,
 either [from packages](https://wiki.fd.io/view/VPP/Installing_VPP_binaries_from_packages) or 
 [from sources](https://wiki.fd.io/view/VPP/Build,_install,_and_test_images#Build_A_VPP_Package).
 
 To build & install `vpp-dev` from sources:
+
 ```
 git clone https://gerrit.fd.io/r/vpp
 cd vpp
@@ -104,7 +113,8 @@ cd build-root
 sudo dpkg -i vpp*.deb
 ```
 
-To build & install all govpp binaries into your `$GOPATH`:
+To build & install all GoVPP binaries into your `$GOPATH`:
+
 ```
 go get git.fd.io/govpp.git
 cd $GOPATH/src/git.fd.io/govpp.git
@@ -112,8 +122,8 @@ make
 make install
 ```
 
-
 ## Building Go bindings from VPP binary APIs
+
 Once you have `binapi-generator` installed in your `$GOPATH`, you can use it to generate Go bindings from
 VPP APis in JSON format. The JSON input can be specified as a single file (`input-file` argument), or
 as a directory that will be scanned for all `.json` files (`input-dir`). The generated Go bindings will
@@ -129,16 +139,7 @@ In Go, [go generate](https://blog.golang.org/generate) tool can be leveraged to
 process. It allows to specify generator instructions in any one of the regular (non-generated) `.go` files
 that are dependent on generated code using special comments, e.g. the one from 
 [example client](examples/cmd/simple-client/simple_client.go):
-```go
-// go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
-```
-
-The comment must start at the beginning of the line and have no spaces between the `//` and the `go:generate`. 
-After that marker, the rest of the line specifies a command for `go generate` to run. 
 
-The `go generate` tool automatically traverses the code base, looks for the special comments in Go code and 
-invokes the code generation, e.g.:
-```
-go generate ./...
+```go
+//go:generate binapi-generator --input-dir=bin_api --output-dir=bin_api
 ```
-Invokes all `go:generate` rules in all Go packages recursively.