From 849e2f3d4e1975bf02cfc7d2b32534294780a53b Mon Sep 17 00:00:00 2001
From: Valentin Rothberg <rothberg@redhat.com>
Date: Mon, 8 Jul 2019 15:28:39 +0200
Subject: analyses: add dependency-tree.sh

Add a new analysis script to print the dependency tree.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
---
 dependencies/analyses/README.md          | 23 +++++++++++++++++++++++
 dependencies/analyses/dependency-tree.sh | 13 +++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100755 dependencies/analyses/dependency-tree.sh

diff --git a/dependencies/analyses/README.md b/dependencies/analyses/README.md
index 70de3f621..2c6e4ca2e 100644
--- a/dependencies/analyses/README.md
+++ b/dependencies/analyses/README.md
@@ -1,5 +1,8 @@
 # A set of scripts and instructions that help to analyze and debloat go-lang dependencies.
 
+Note that all scripts mentioned below follow the [KISS principle](https://en.wikipedia.org/wiki/KISS_principle) on purpose.
+The scripts are meant to be used in combination to aid in undestanding the packages' dependencies and how they contribute to the size of the compiled binary.
+
 ## Size of packages
 
 To analyze the size of all go packages used during the build process, pass the `-work -a` build flags to `go build`.
@@ -62,3 +65,23 @@ Running such an analysis on libpod may look as follows:
 ```
 
 Running the script can help identify sources of bloat and reveal potential candidates (e.g., entire packages, types, or function) for refactoring.
+
+
+## Dependency Tree
+
+Use the `dependency-tree.sh` script to figure out which package including which packages.
+The output of the script has the format `package: dependency_1, dependency_2, ...`.
+Each line is followed by a blank link to make it easier to read.
+Note that the list of dependencies includes only the direct dependencies and not all transitive dependencies.
+The transitive dependencies of a given package can be examined by running `go list -f '{{ .Name }}: {{ join .Deps ", " }}' $PACKAGE` or by browsing through the output of `dependency-tree.sh`.
+
+Running such a dependency-tree analysis may look as follows:
+
+
+```
+[libpod]$ ./dependencies/analyses/dependency-tree.sh github.com/containers/libpod > tree.txt
+[libpod]$ grep "^github.com/containers/libpod/pkg/registries" tree.txt
+github.com/containers/libpod/pkg/registries: github.com/containers/libpod/vendor/github.com/containers/image/pkg/sysregistriesv2, github.com/containers/libpod/vendor/github.com/containers/image/types, github.com/containers/libpod/pkg/rootless, github.com/containers/libpod/vendor/github.com/docker/distribution/reference, github.com/containers/libpod/vendor/github.com/pkg/errors, os, path/filepath, strings
+```
+
+As shown above, the script's output can then be used to query for specific packages.
diff --git a/dependencies/analyses/dependency-tree.sh b/dependencies/analyses/dependency-tree.sh
new file mode 100755
index 000000000..3c9dccc51
--- /dev/null
+++ b/dependencies/analyses/dependency-tree.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/bash
+
+if test "$#" -ne 1; then
+	echo "invalid arguments: usage: $0 path to package"
+	exit 1
+fi
+
+DATA=$(go list $1/... \
+	| xargs -d '\n' go list -f '{{ .ImportPath }}: {{ join .Imports ", " }}' \
+	| awk '{ printf "%s\n\n", $0 }' \
+	)
+
+echo "$DATA"
-- 
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