From 7b58366a10fdb0c57f94f96cf519cc4118684d16 Mon Sep 17 00:00:00 2001
From: Nate Jones <nate@endot.org>
Date: Mon, 17 Aug 2015 19:44:02 -0700
Subject: [PATCH 1/2] add stub for help

---
 containers.go |  2 +-
 help.go       | 22 ++++++++++++++++++++++
 images.go     |  2 +-
 3 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 help.go

diff --git a/containers.go b/containers.go
index 2029a42..2db8415 100644
--- a/containers.go
+++ b/containers.go
@@ -57,7 +57,7 @@ func (x *ContainersCommand) Execute(args []string) error {
 
 		clientContainers, err := client.ListContainers(docker.ListContainersOptions{All: true})
 		if err != nil {
-			return err
+			return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
 		}
 
 		var conts []Container
diff --git a/help.go b/help.go
new file mode 100644
index 0000000..a03ad06
--- /dev/null
+++ b/help.go
@@ -0,0 +1,22 @@
+package main
+
+import "fmt"
+
+type HelpCommand struct {
+	// nothing yet
+}
+
+var helpCommand HelpCommand
+
+func (x *HelpCommand) Execute(args []string) error {
+	fmt.Println("stub help is here")
+
+	return nil
+}
+
+func init() {
+	parser.AddCommand("help",
+		"Help for this tool.",
+		"",
+		&helpCommand)
+}
diff --git a/images.go b/images.go
index bfe3289..605f323 100644
--- a/images.go
+++ b/images.go
@@ -59,7 +59,7 @@ func (x *ImagesCommand) Execute(args []string) error {
 
 		clientImages, err := client.ListImages(docker.ListImagesOptions{All: true})
 		if err != nil {
-			return err
+			return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
 		}
 
 		var ims []Image

From b911e691800f7dbe762c4d8ee4d438ee21c336f8 Mon Sep 17 00:00:00 2001
From: Nate Jones <nate@endot.org>
Date: Tue, 18 Aug 2015 06:33:22 -0700
Subject: [PATCH 2/2] fill in help, add hint when running in docker

---
 Dockerfile    |  1 +
 containers.go |  6 +++++-
 help.go       | 24 ++++++++++++++++++++++--
 images.go     |  6 +++++-
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index d1ef506..b35fb5b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,4 @@
 FROM scratch
 COPY dockviz /
+ENV IN_DOCKER true
 ENTRYPOINT ["/dockviz"]
diff --git a/containers.go b/containers.go
index 2db8415..c42f471 100644
--- a/containers.go
+++ b/containers.go
@@ -57,7 +57,11 @@ func (x *ContainersCommand) Execute(args []string) error {
 
 		clientContainers, err := client.ListContainers(docker.ListContainersOptions{All: true})
 		if err != nil {
-			return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
+			if in_docker := os.Getenv("IN_DOCKER"); len(in_docker) > 0 {
+				return fmt.Errorf("Unable to access Docker socket, please run like this:\n  docker run --rm -v /var/run/docker.sock:/var/run/docker.sock nate/dockviz containers <args>\nFor more help, run 'dockviz help'")
+			} else {
+				return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
+			}
 		}
 
 		var conts []Container
diff --git a/help.go b/help.go
index a03ad06..6dae6f9 100644
--- a/help.go
+++ b/help.go
@@ -9,14 +9,34 @@ type HelpCommand struct {
 var helpCommand HelpCommand
 
 func (x *HelpCommand) Execute(args []string) error {
-	fmt.Println("stub help is here")
+	fmt.Println(`Dockviz: Visualizing Docker Data
+
+Connecting to Docker:
+
+Dockviz supports connecting to the Docker daemon directly.  It defaults to
+'unix:///var/run/docker.sock', but respects the following as well:
+
+* The 'DOCKER_HOST', 'DOCKER_CERT_PATH', and 'DOCKER_TLS_VERIFY' environment
+  variables, as set up by boot2docker or docker-machine.
+* Command line arguments (e.g. '--tlscacert'), like those that Docker itself
+  supports.
+
+Dockviz also supports receiving Docker image or container json data on standard
+input: curl -s http://localhost:4243/images/json?all=1 | dockviz images --tree
+
+Visualizing:
+
+Dockviz can visualize both images and containers. For more information on the
+options each subcommand supports, run them with the '--help' flag (e.g.
+'dockviz images --help').
+`)
 
 	return nil
 }
 
 func init() {
 	parser.AddCommand("help",
-		"Help for this tool.",
+		"Help for dockviz.",
 		"",
 		&helpCommand)
 }
diff --git a/images.go b/images.go
index 605f323..018a85b 100644
--- a/images.go
+++ b/images.go
@@ -59,7 +59,11 @@ func (x *ImagesCommand) Execute(args []string) error {
 
 		clientImages, err := client.ListImages(docker.ListImagesOptions{All: true})
 		if err != nil {
-			return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
+			if in_docker := os.Getenv("IN_DOCKER"); len(in_docker) > 0 {
+				return fmt.Errorf("Unable to access Docker socket, please run like this:\n  docker run --rm -v /var/run/docker.sock:/var/run/docker.sock nate/dockviz images <args>\nFor more help, run 'dockviz help'")
+			} else {
+				return fmt.Errorf("Unable to connect: %s\nFor help, run 'dockviz help'", err)
+			}
 		}
 
 		var ims []Image