docs: add BUILD.md, development guide

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/BUILD.md b/BUILD.md
new file mode 100644
index 00000000..8dc9cc2c
--- /dev/null
+++ b/BUILD.md
@@ -0,0 +1,22 @@
+# Development Guide
+
+## Building the development environment
+
+You need a working [Go environment](https://golang.org/doc/install) (1.11 or newer).
+
+```bash
+$ go get -u github.com/golang/dep/cmd/dep
+$ go get github.com/osrg/gobgp
+$ cd $GOPATH/src/github.com/osrg/gobgp && dep ensure
+```
+
+Now ready to build two binaries, `cmd/gobgp` and `cmd/gobgpd`.
+
+## Changing the gRPC API
+
+If you change the gRPC API, generate `api/gobgp.pb.go` in the following way:
+
+```bash
+$ protoc -I ~/protobuf/src -I ${GOBGP}/api --go_out=plugins=grpc:${GOBGP}/api \
+         ${GOBGP}/api/gobgp.proto ${GOBGP}/api/attribute.proto ${GOBGP}/api/capability.proto
+```