feat(agent): use air to reloader and dlv as debugger

The Air utility is a more modern, widely used binary loader and well
currently maintained, which makes it a better option than the previous
one, the Refresh. Another addition is the use of Delve, a Golang
debugger, to facilitate the bugging process for the ShellHub Agent in
the host environment.

NOTE: This change only affects the development environment.

A good extra could append the `substitute-path` configuration to the
"~/.config/dlv/config.yml" to substitute the reference to the source
code inside the container for the host's one.

.gitignore

@@ -17,6 +17,7 @@ go.work
 go.work.sum
 connector/.keys
 connector/connector
+*/tmp
 
 # Directory used by devscripts/run-agent to store binaries
 bin/agent

agent/.air.toml

@@ -0,0 +1,32 @@
+root = "."
+tmp_dir = "tmp"
+
+[build]
+pre_cmd = ["rm ./tmp/dlv.sock"]
+cmd = "go build -tags docker -ldflags \"-X main.AgentVersion=latest\" -gcflags=\"all=-N -l\" -o ./tmp/main ."
+post_cmd = []
+bin = ""
+full_bin = "dlv exec ./tmp/main"
+args_bin = [
+  "--listen unix:./tmp/dlv.sock",
+  "--headless",
+  "--continue",
+  "--accept-multiclient",
+]
+delay = 1000
+exclude_dir = ["assets", "tmp", "vendor", "testdata"]
+exclude_file = []
+exclude_regex = ["_test.go"]
+exclude_unchanged = false
+follow_symlink = false
+include_dir = []
+include_ext = ["go", "tpl", "tmpl", "html"]
+include_file = []
+kill_delay = "0s"
+log = "build-errors.log"
+poll = false
+poll_interval = 0
+rerun = false
+rerun_delay = 500
+send_interrupt = false
+stop_on_error = false

agent/Dockerfile

@@ -51,7 +51,8 @@ ARG GOPROXY
 ENV GOPROXY ${GOPROXY}
 
 RUN apk add --update openssl openssh-client
-RUN go install github.com/markbates/[email protected] && \
+RUN go install github.com/air-verse/[email protected] && \
+    go install github.com/go-delve/delve/cmd/[email protected] && \
     go install github.com/golangci/golangci-lint/cmd/[email protected]
 
 WORKDIR $GOPATH/src/github.com/shellhub-io/shellhub

agent/entrypoint-dev.sh

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-refresh run
+air