feat: add peerlog plugin

docs/plugins.md

@@ -127,6 +127,13 @@ To preload a go-ipfs plugin:
 go-ipfs$ make build
 ```
 
+You can also preload an in-tree but disabled-by-default plugin by adding it to
+the IPFS_PLUGINS variable. For example, to enable plugins foo, bar, and baz:
+
+```bash
+go-ipfs$ make build IPFS_PLUGINS="foo bar baz"
+```
+
 ## Creating A Plugin
 
 To create your own out-of-tree plugin, use the [example

plugin/loader/Rules.mk

@@ -1,10 +1,13 @@
 include mk/header.mk
 
+IPFS_PLUGINS ?= 
+export IPFS_PLUGINS
+
 $(d)/preload.go: d:=$(d)
-$(d)/preload.go: $(d)/preload_list $(d)/preload.sh
+$(d)/preload.go: $(d)/preload_list $(d)/preload.sh ALWAYS
 	$(d)/preload.sh > $@
 	go fmt $@ >/dev/null
 
 DEPS_GO += $(d)/preload.go
-	
+
 include mk/footer.mk

plugin/loader/preload.sh

@@ -4,6 +4,11 @@ DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
 to_preload() {
 	awk 'NF' "$DIR/preload_list" | sed '/^#/d'
+  if [[ -n "$IPFS_PLUGINS" ]]; then
+      for plugin in $IPFS_PLUGINS; do
+          echo "$plugin github.com/ipfs/go-ipfs/plugin/plugins/$plugin *"
+      done
+  fi
 }
 
 cat <<EOL

plugin/plugins/peerlog/peerlog.go

@@ -0,0 +1,69 @@
+package peerlog
+
+import (
+	"fmt"
+
+	core "github.com/ipfs/go-ipfs/core"
+	plugin "github.com/ipfs/go-ipfs/plugin"
+	logging "github.com/ipfs/go-log"
+	network "github.com/libp2p/go-libp2p-core/network"
+)
+
+var log = logging.Logger("plugin/peerlog")
+
+// Log all the PeerIDs we see
+//
+// Usage:
+//   GOLOG_FILE=~/peer.log IPFS_LOGGING_FMT=json ipfs daemon
+// Output:
+//   {"level":"info","ts":"2020-02-10T13:54:26.639Z","logger":"plugin/peerlog","caller":"peerlog/peerlog.go:51","msg":"connected","peer":"QmS2H72gdrekXJggGdE9SunXPntBqdkJdkXQJjuxcH8Cbt"}
+//   {"level":"info","ts":"2020-02-10T13:54:59.095Z","logger":"plugin/peerlog","caller":"peerlog/peerlog.go:56","msg":"disconnected","peer":"QmS2H72gdrekXJggGdE9SunXPntBqdkJdkXQJjuxcH8Cbt"}
+//
+type peerLogPlugin struct{}
+
+var _ plugin.PluginDaemonInternal = (*peerLogPlugin)(nil)
+
+// Plugins is exported list of plugins that will be loaded
+var Plugins = []plugin.Plugin{
+	&peerLogPlugin{},
+}
+
+// Name returns the plugin's name, satisfying the plugin.Plugin interface.
+func (*peerLogPlugin) Name() string {
+	return "peerlog"
+}
+
+// Version returns the plugin's version, satisfying the plugin.Plugin interface.
+func (*peerLogPlugin) Version() string {
+	return "0.1.0"
+}
+
+// Init initializes plugin
+func (*peerLogPlugin) Init(*plugin.Environment) error {
+	fmt.Println("peerLogPlugin enabled - PeerIDs will be logged")
+	return nil
+}
+
+func (*peerLogPlugin) Start(node *core.IpfsNode) error {
+	// Ensure logs from this plugin get printed regardless of global IPFS_LOGGING value
+	if err := logging.SetLogLevel("plugin/peerlog", "info"); err != nil {
+		return fmt.Errorf("failed to set log level: %w", err)
+	}
+	var notifee network.NotifyBundle
+	notifee.ConnectedF = func(net network.Network, conn network.Conn) {
+		log.Infow("connected",
+			"peer", conn.RemotePeer().Pretty(),
+		)
+	}
+	notifee.DisconnectedF = func(net network.Network, conn network.Conn) {
+		log.Infow("disconnected",
+			"peer", conn.RemotePeer().Pretty(),
+		)
+	}
+	node.PeerHost.Network().Notify(&notifee)
+	return nil
+}
+
+func (*peerLogPlugin) Close() error {
+	return nil
+}