From 95a9ee75718489353ddb45fc596652973e3ade06 Mon Sep 17 00:00:00 2001
From: "M. Mert Yildiran" <mehmet@up9.com>
Date: Tue, 17 Aug 2021 05:56:56 +0300
Subject: [PATCH] Add a build script to automatically build extensions from a
 known path and load them

---
 Makefile                     | 10 ++--------
 build_extensions.sh          | 12 ++++++++++++
 tap/extensions/amqp/go.mod   |  3 +++
 tap/extensions/amqp/main.go  | 18 ++++++++++++++++++
 tap/extensions/http/go.sum   | 20 --------------------
 tap/extensions/http/main.go  |  8 ++++++--
 tap/extensions/kafka/go.mod  |  3 +++
 tap/extensions/kafka/main.go | 18 ++++++++++++++++++
 tap/passive_tapper.go        | 33 +++++++++++++++++++++------------
 9 files changed, 83 insertions(+), 42 deletions(-)
 create mode 100755 build_extensions.sh
 create mode 100644 tap/extensions/amqp/go.mod
 create mode 100644 tap/extensions/amqp/main.go
 delete mode 100644 tap/extensions/http/go.sum
 create mode 100644 tap/extensions/kafka/go.mod
 create mode 100644 tap/extensions/kafka/main.go

diff --git a/Makefile b/Makefile
index bdabb325e..a82fed4ec 100644
--- a/Makefile
+++ b/Makefile
@@ -66,11 +66,5 @@ clean-cli:  ## Clean CLI.
 clean-docker:
 	@(echo "DOCKER cleanup - NOT IMPLEMENTED YET " )
 
-extensions: extension-http
-
-extension-http:
-	cd tap/extensions/http && \
-	go build -buildmode=plugin -o ../http.so .
-	cd ../../..
-	mkdir -p agent/build/extensions
-	cp tap/extensions/http.so agent/build/extensions
+extensions:
+	./build_extensions.sh
diff --git a/build_extensions.sh b/build_extensions.sh
new file mode 100755
index 000000000..855f1c44a
--- /dev/null
+++ b/build_extensions.sh
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+for f in tap/extensions/*; do
+    if [ -d "$f" ]; then
+        extension=$(basename $f) && \
+        cd tap/extensions/${extension} && \
+        go build -buildmode=plugin -o ../${extension}.so .  && \
+        cd ../../..  && \
+        mkdir -p agent/build/extensions  && \
+        cp tap/extensions/${extension}.so agent/build/extensions
+    fi
+done
diff --git a/tap/extensions/amqp/go.mod b/tap/extensions/amqp/go.mod
new file mode 100644
index 000000000..ff01d605e
--- /dev/null
+++ b/tap/extensions/amqp/go.mod
@@ -0,0 +1,3 @@
+module github.com/up9inc/mizu/tap/extensions/amqp
+
+go 1.16
diff --git a/tap/extensions/amqp/main.go b/tap/extensions/amqp/main.go
new file mode 100644
index 000000000..e089f1f3b
--- /dev/null
+++ b/tap/extensions/amqp/main.go
@@ -0,0 +1,18 @@
+package main
+
+import (
+	"log"
+)
+
+func init() {
+	log.Println("Initializing AMQP extension.")
+}
+
+type greeting string
+
+func (g greeting) Greet() {
+	log.Println("Hello from AMQP extension.")
+}
+
+// exported as symbol named "Greeter"
+var Greeter greeting
diff --git a/tap/extensions/http/go.sum b/tap/extensions/http/go.sum
deleted file mode 100644
index d7824c2dc..000000000
--- a/tap/extensions/http/go.sum
+++ /dev/null
@@ -1,20 +0,0 @@
-github.com/bradleyfalzon/tlsx v0.0.0-20170624122154-28fd0e59bac4 h1:NJOOlc6ZJjix0A1rAU+nxruZtR8KboG1848yqpIUo4M=
-github.com/bradleyfalzon/tlsx v0.0.0-20170624122154-28fd0e59bac4/go.mod h1:DQPxZS994Ld1Y8uwnJT+dRL04XPD0cElP/pHH/zEBHM=
-github.com/google/martian v2.1.0+incompatible h1:/CP5g8u/VJHijgedC/Legn3BAbAaWPgecwXBIDzw5no=
-github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
-github.com/orcaman/concurrent-map v0.0.0-20210501183033-44dafcb38ecc h1:Ak86L+yDSOzKFa7WM5bf5itSOo1e3Xh8bm5YCMUXIjQ=
-github.com/orcaman/concurrent-map v0.0.0-20210501183033-44dafcb38ecc/go.mod h1:Lu3tH6HLW3feq74c2GC+jIMS/K2CFcDWnWD9XkenwhI=
-github.com/romana/rlog v0.0.0-20171115192701-f018bc92e7d7 h1:jkvpcEatpwuMF5O5LVxTnehj6YZ/aEZN4NWD/Xml4pI=
-github.com/romana/rlog v0.0.0-20171115192701-f018bc92e7d7/go.mod h1:KTrHyWpO1sevuXPZwyeZc72ddWRFqNSKDFl7uVWKpg0=
-golang.org/x/net v0.0.0-20210421230115-4e50805a0758 h1:aEpZnXcAmXkd6AvLb2OPt+EN1Zu/8Ne3pCqPjja5PXY=
-golang.org/x/net v0.0.0-20210421230115-4e50805a0758/go.mod h1:72T/g9IO56b78aLF+1Kcs5dz7/ng1VjMUvfKvpfy+jM=
-golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d h1:LO7XpTYMwTqxjLcGWPijK3vRXg1aWdlNOVOHRq45d7c=
-golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210420072515-93ed5bcd2bfe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
diff --git a/tap/extensions/http/main.go b/tap/extensions/http/main.go
index a7fd32544..123165dd0 100644
--- a/tap/extensions/http/main.go
+++ b/tap/extensions/http/main.go
@@ -1,13 +1,17 @@
 package main
 
 import (
-	"fmt"
+	"log"
 )
 
+func init() {
+	log.Println("Initializing HTTP extension.")
+}
+
 type greeting string
 
 func (g greeting) Greet() {
-	fmt.Println("Hello HTTP")
+	log.Println("Hello from HTTP extension.")
 }
 
 // exported as symbol named "Greeter"
diff --git a/tap/extensions/kafka/go.mod b/tap/extensions/kafka/go.mod
new file mode 100644
index 000000000..8f5ef9de6
--- /dev/null
+++ b/tap/extensions/kafka/go.mod
@@ -0,0 +1,3 @@
+module github.com/up9inc/mizu/tap/extensions/kafka
+
+go 1.16
diff --git a/tap/extensions/kafka/main.go b/tap/extensions/kafka/main.go
new file mode 100644
index 000000000..a5adc91fc
--- /dev/null
+++ b/tap/extensions/kafka/main.go
@@ -0,0 +1,18 @@
+package main
+
+import (
+	"log"
+)
+
+func init() {
+	log.Println("Initializing Kafka extension.")
+}
+
+type greeting string
+
+func (g greeting) Greet() {
+	log.Println("Hello from Kafka extension.")
+}
+
+// exported as symbol named "Greeter"
+var Greeter greeting
diff --git a/tap/passive_tapper.go b/tap/passive_tapper.go
index afb3e1a9f..9c3d56192 100644
--- a/tap/passive_tapper.go
+++ b/tap/passive_tapper.go
@@ -12,6 +12,7 @@ import (
 	"encoding/hex"
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"os"
 	"os/signal"
@@ -253,19 +254,27 @@ func startMemoryProfiler() {
 
 func loadExtensions() {
 	dir, _ := filepath.Abs(filepath.Dir(os.Args[0]))
-	abspath := path.Join(dir, "./extensions/http.so")
-	fmt.Printf("abspath: %v\n", abspath)
-	extension := &Extension{
-		Name: "http",
-		Path: abspath,
-	}
-	plug, _ := plugin.Open(extension.Path)
-	extension.Plug = plug
-	symGreeter, _ := plug.Lookup("Greeter")
+	extensionsDir := path.Join(dir, "./extensions/")
 
-	var greeter Greeter
-	greeter, _ = symGreeter.(Greeter)
-	greeter.Greet()
+	files, err := ioutil.ReadDir(extensionsDir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for _, file := range files {
+		filename := file.Name()
+		log.Printf("Loading extension: %s\n", filename)
+		extension := &Extension{
+			Name: strings.TrimSuffix(filename, filepath.Ext(filename)),
+			Path: path.Join(extensionsDir, filename),
+		}
+		plug, _ := plugin.Open(extension.Path)
+		extension.Plug = plug
+		symGreeter, _ := plug.Lookup("Greeter")
+
+		var greeter Greeter
+		greeter, _ = symGreeter.(Greeter)
+		greeter.Greet()
+	}
 }
 
 func startPassiveTapper(outboundLinkWriter *OutboundLinkWriter) {