From 9baba96f8931f39ffef6f0f762a7c420d6d7bd4c Mon Sep 17 00:00:00 2001
From: zimbatm <zimbatm@zimbatm.com>
Date: Fri, 8 Feb 2019 21:15:38 +0100
Subject: [PATCH] abstract CLI image generation

and add busybox in all the images
---
 curl/default.nix            | 20 +++-----------------
 docker-compose/default.nix  | 20 +++-----------------
 kubectl/default.nix         | 20 +++-----------------
 kubernetes-helm/default.nix | 21 ++++-----------------
 lib/buildCLIImage.nix       | 27 +++++++++++++++++++++++++++
 overlay.nix                 |  3 +++
 6 files changed, 43 insertions(+), 68 deletions(-)
 create mode 100644 lib/buildCLIImage.nix

diff --git a/curl/default.nix b/curl/default.nix
index 379ab51..ff98b29 100644
--- a/curl/default.nix
+++ b/curl/default.nix
@@ -1,20 +1,6 @@
-{ dockerTools
-, cacert
+{ buildCLIImage
 , curl
 }:
-dockerTools.buildLayeredImage {
-  inherit (curl) name;
-
-  contents = [
-    cacert
-    curl
-  ];
-
-  config = {
-    Entrypoint = [ "/bin/curl" ];
-    Env = [
-      "PATH=/bin"
-      "SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt"
-    ];
-  };
+buildCLIImage {
+  drv = curl;
 }
diff --git a/docker-compose/default.nix b/docker-compose/default.nix
index 76577c0..6751321 100644
--- a/docker-compose/default.nix
+++ b/docker-compose/default.nix
@@ -1,20 +1,6 @@
-{ dockerTools
-, cacert
+{ buildCLIImage
 , docker-compose
 }:
-dockerTools.buildLayeredImage {
-  inherit (docker-compose) name;
-
-  contents = [
-    cacert
-    docker-compose
-  ];
-
-  config = {
-    Entrypoint = [ "/bin/docker-compose" ];
-    Env = [
-      "PATH=/bin"
-      "SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt"
-    ];
-  };
+buildCLIImage {
+  drv = docker-compose;
 }
diff --git a/kubectl/default.nix b/kubectl/default.nix
index 6619fac..4e5fec0 100644
--- a/kubectl/default.nix
+++ b/kubectl/default.nix
@@ -1,20 +1,6 @@
-{ dockerTools
-, cacert
+{ buildCLIImage
 , kubectl
 }:
-dockerTools.buildLayeredImage {
-  inherit (kubectl) name;
-
-  contents = [
-    cacert
-    kubectl
-  ];
-
-  config = {
-    Entrypoint = [ "/bin/kubectl" ];
-    Env = [
-      "PATH=/bin"
-      "SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt"
-    ];
-  };
+buildCLIImage {
+  drv = kubectl;
 }
diff --git a/kubernetes-helm/default.nix b/kubernetes-helm/default.nix
index 9c90114..c994f4f 100644
--- a/kubernetes-helm/default.nix
+++ b/kubernetes-helm/default.nix
@@ -1,20 +1,7 @@
-{ dockerTools
-, cacert
+{ buildCLIImage
 , kubernetes-helm
 }:
-dockerTools.buildLayeredImage {
-  inherit (kubernetes-helm) name;
-
-  contents = [
-    cacert
-    kubernetes-helm
-  ];
-
-  config = {
-    Entrypoint = [ "/bin/helm" ];
-    Env = [
-      "PATH=/bin"
-      "SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt"
-    ];
-  };
+buildCLIImage {
+  drv = kubernetes-helm;
+  binName = "helm";
 }
diff --git a/lib/buildCLIImage.nix b/lib/buildCLIImage.nix
new file mode 100644
index 0000000..24c8515
--- /dev/null
+++ b/lib/buildCLIImage.nix
@@ -0,0 +1,27 @@
+{ dockerTools
+, busybox
+, cacert
+}:
+{ drv # derivation to build the image for
+# Name of the binary to run by default
+, binName ? (builtins.parseDrvName drv.name).name
+}:
+dockerTools.buildLayeredImage {
+  name = drv.name;
+
+  contents = [
+    # add a /bin/sh on all images
+    busybox
+    # most program need TLS certs
+    cacert
+    drv
+  ];
+
+  config = {
+    Cmd = [ "/bin/${binName}" ];
+    Env = [
+      "PATH=/bin"
+      "SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt"
+    ];
+  };
+}
diff --git a/overlay.nix b/overlay.nix
index e7a64f4..abd6e0c 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -1,4 +1,7 @@
 _: pkgs: {
+  # lib stuff can be in the top-level
+  buildCLIImage = pkgs.callPackage ./lib/buildCLIImage.nix {};
+
   # docker images must be lower-cased
   docker-nixpkgs = rec {