From 1d55202ec5bbe851c0764072badfca9f9b6ba632 Mon Sep 17 00:00:00 2001
From: Bartosz Leper <bartosz.leper@goteleport.com>
Date: Tue, 28 Nov 2023 15:01:45 +0100
Subject: [PATCH] Support running Teleport in a "hot reload" mode

This change follows the example of our Cloud project which uses the same solution under the hood.
---
 Makefile  |  5 +++++
 README.md | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/Makefile b/Makefile
index 00a6290a029ee..d080b09c99593 100644
--- a/Makefile
+++ b/Makefile
@@ -296,6 +296,11 @@ $(BUILDDIR)/tctl:
 $(BUILDDIR)/teleport: ensure-webassets bpf-bytecode rdpclient
 	GOOS=$(OS) GOARCH=$(ARCH) $(CGOFLAG) go build -tags "webassets_embed $(PAM_TAG) $(FIPS_TAG) $(BPF_TAG) $(WEBASSETS_TAG) $(RDPCLIENT_TAG) $(PIV_BUILD_TAG)" -o $(BUILDDIR)/teleport $(BUILDFLAGS) ./tool/teleport
 
+TELEPORT_ARGS ?= start
+.PHONY: teleport-hot-reload
+teleport-hot-reload:
+	CompileDaemon --graceful-kill=true --exclude-dir=".git" --exclude-dir="node_modules" --build="make $(BUILDDIR)/teleport" --command="$(BUILDDIR)/teleport $(TELEPORT_ARGS)"
+
 # NOTE: Any changes to the `tsh` build here must be copied to `windows.go` in Dronegen until
 # 		we can use this Makefile for native Windows builds.
 .PHONY: $(BUILDDIR)/tsh
diff --git a/README.md b/README.md
index bc5d2fd784927..138e6373c6c40 100644
--- a/README.md
+++ b/README.md
@@ -213,6 +213,41 @@ sudo mkdir -p -m0700 /var/lib/teleport
 sudo chown $USER /var/lib/teleport
 ```
 
+#### Running Teleport in a hot reload mode
+
+To speed up your development process, you can run Teleport using
+[`CompileDaemon`](https://github.com/githubnemo/CompileDaemon). This will build
+and run the Teleport binary, and then rebuild and restart it whenever any Go
+source files change.
+
+1. Install CompileDaemon:
+
+    ```shell
+    go install github.com/githubnemo/CompileDaemon@latest
+    ```
+
+    Note that we use `go install` instead of the suggested `go get`, because we
+    don't want CompileDaemon to become a dependency of the project.
+
+1. Build and run the Teleport binary:
+
+    ```shell
+    make teleport-hot-reload
+    ```
+
+    By default, this runs a `teleport start` command. If you want to customize
+    the command, for example by providing a custom config file location, you can
+    use the `TELEPORT_ARGS` parameter:
+
+    ```shell
+    make teleport-hot-reload TELEPORT_ARGS='start --config=/path/to/config.yaml'
+    ```
+
+Note that you still need to run [`make grpc`](api/proto/README.md) if you modify
+any Protocol Buffers files to regenerate the generated Go sources; regenerating
+these sources should in turn cause the CompileDaemon to rebuild and restart
+Teleport.
+
 ### Web UI
 
 The Teleport Web UI resides in the [web](web) directory.