feat: per-type adoption

.github/workflows/ci.yml

@@ -0,0 +1,16 @@
+name: CI
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+  merge_group:
+    branches: ["main"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: extractions/setup-just@v1
+      - run: just test

examples/adopt.golden

@@ -0,0 +1,64 @@
+---
+apiVersion: v1
+data:
+  bar: baz
+kind: ConfigMap
+metadata:
+  name: foo
+  namespace: myns
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+  namespace: myns
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      annotations:
+        kubectl.kubernetes.io/default-container: nginx
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - env:
+        - name: BAR
+          valueFrom:
+            configMapKeyRef:
+              key: bar
+              name: foo
+        - name: COMMON_ENV
+          value: example common env
+        image: nginx:1.14.2
+        name: nginx
+        ports:
+        - containerPort: 80
+          name: http
+        volumeMounts: []
+      - env:
+        - name: FOO
+          value: bar
+        image: my.dummy/sidecar
+        name: side
+        ports: []
+        volumeMounts: []
+      foo: 42
+      initContainers: []
+      volumes: []
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+  namespace: myns
+spec:
+  ports:
+  - name: http
+    port: 80
+    targetPort: http
+  selector:
+    app: nginx

examples/adopt.jsonnet

@@ -3,6 +3,24 @@
     ObjectMeta: {
       namespace: 'myns',
     },
+    v1+: {
+      PodSpec+: {
+        foo: 42,
+        containers_+: {
+          side+: {
+            image: 'my.dummy/sidecar',
+            env_+: {
+              FOO: { value: 'bar' },
+            },
+          },
+        },
+      },
+      Container+: {
+        env_+: {
+          COMMON_ENV+: { value: 'example common env' },
+        },
+      },
+    },
   },
 
   upstream: $.k8s.adopt(std.parseYaml(importstr 'adopt.yaml')),

justfile

@@ -0,0 +1,17 @@
+#!/usr/bin/env just --justfile
+
+export KUBECFG_ALPHA := "true"
+
+test:
+    @ find . -name "*.jsonnet" -exec just assert {} \;
+    @ find . -name "*.golden" -exec just golden {} \;
+
+golden FILE:
+    #!/bin/bash
+    golden={{FILE}}
+    jsonnet=${golden%%.golden}.jsonnet
+    diff "${golden}" <(kubecfg show "${jsonnet}")
+
+assert FILE:
+    #!/bin/bash
+    kubecfg eval {{FILE}} >/dev/null

k8s.libsonnet

@@ -13,6 +13,10 @@ local kubecfg = import 'kubecfg.libsonnet';
   // generic helpers
   // -------------------------
 
+  // workaround for https://github.com/google/go-jsonnet/issues/736
+  // local objectHas(o, f) = std.objectHas(o, f),
+  local objectHas(o, f) = std.setMember(f, std.objectFields(o)),
+
   // applies overlay to each field of obj.
   applyOverlayEach(obj, overlay):: $.mapObject(function(v) v + overlay, obj),
 
@@ -23,7 +27,7 @@ local kubecfg = import 'kubecfg.libsonnet';
   // mapObject applies f to all the values of the o object. Unlike std.mapWithKey, the "hidden" property of the fields is preserved.
   mapObject(f, o):: std.foldl(function(acc, i) acc + (
     local v = f(o[i]);
-    if std.objectHas(o, i) then { [i]: v } else { [i]:: v }
+    if objectHas(o, i) then { [i]: v } else { [i]:: v }
   ), std.objectFieldsAll(o), {}),
 
   // Like std.objectValues but adds a `[key`] field with the key of each element.
@@ -206,7 +210,33 @@ local kubecfg = import 'kubecfg.libsonnet';
     acc {
       [name + '_']+:: {},
       [name]: $.asNamedArray($.deriveEach(type, self[name + '_'])),
-    }, arr, {}),
+    }, arr, { [adoptUpstreamKey]:: adopterFromTypedNamedArrays(arr) }),
+  local adoptUpstreamKey = '_adoptUpstream',
+
+  // This function returns the "adopter" function for a given partial type (object subtree).
+  // The adopter function logically performs the inverse function of typedNamedArrays.
+  local adopterFromPartialType(obj) = std.get(obj, adoptUpstreamKey, function(o) o),
+
+  // returns a function that will convert an upstream object into an object in the style of what users of this library
+  // would have crafted, according to the "typed named array" field definitions (containers -> containers_, env -> env_, ...).
+  // `arr` is an array of field definitions. A field definition is either string (the name of a field, e.g. 'containers')
+  // or in turn an tuple of [field_name, element_type]
+  local adopterFromTypedNamedArrays(arr) = function(o) std.foldl(
+    function(acc, d) adoptNamedArray(acc, if std.isArray(d) then d else [d, {}]),
+    arr,
+    o
+  ),
+
+  local adoptNamedArray(o, fieldDef) =
+    local name = if std.isArray(fieldDef) then fieldDef[0] else fieldDef;
+    local type = if std.isArray(fieldDef) then fieldDef[1] else {};
+    o {
+      [name + '_']+:: {
+        [i.name]+: i
+        for i in std.get(o, name, [])
+      },
+      [name]: $.asNamedArray($.mapObject(function(v) adoptObject(v, type), self[name + '_'])),
+    },
 
   // "Objectified" array
   //
@@ -233,14 +263,29 @@ local kubecfg = import 'kubecfg.libsonnet';
   local objectEntries(o) = [[k, o[k]] for k in std.objectFields(o)],
 
   // adopt existing resources and make them extend the types defined by the k8s-libsonnet library.
-  adopt(objs):: kubecfg.deepMap(function(o) $.typeFor(o) + kubecfg.toOverlay(o), objs),
+  adopt(objs):: kubecfg.deepMap(function(o) adoptObject(kubecfg.toOverlay(o), $.typeFor(o)), objs),
+
+  local adoptObject(obj, typ) = deepMapObject(adoptObjectSubtree, typ + obj),
+  local adoptObjectSubtree(obj) = adopterFromPartialType(obj)(obj),
 
   typeFor(o)::
     local gv = std.splitLimitR('/' + o.apiVersion, '/', 1),
           gvk = { group: gv[0], version: gv[1], kind: o.kind },
           path = std.lstripChars('%(group)s.%(version)s.%(kind)s' % gvk, './');
     kubecfg.getPath($, path, default=$.Object),
 
+  // deepMapObject(func, o): Apply the given function to each
+  // object in nested collection o, preserving the structure of o.
+  // It traverses arrays but it doesn't invoke the function on on arrays
+  local deepMapObject(func, o) = (
+    if std.isObject(o) then
+      func($.mapObject(function(o) deepMapObject(func, o), o))
+    else if std.isArray(o) then
+      [deepMapObject(func, elem) for elem in o]
+    else o
+  ),
+  assert std.assertEqual('%s' % [deepMapObject(std.toString, { a: { b: [{ c: 1 }] } })], '{"a": "{\\"b\\": [\\"{\\\\\\"c\\\\\\": 1}\\"]}"}'),
+
   // -------------------------
   // types
   // -------------------------
@@ -337,7 +382,9 @@ local kubecfg = import 'kubecfg.libsonnet';
       } else {},
       spec+: v.PodSpec,
     },
-    PodSpec+: $.typedNamedArrays([['containers', v.Container], ['initContainers', v.Container], 'volumes']),
+    PodSpec+: $.typedNamedArrays([['containers', v.Container], ['initContainers', v.Container], 'volumes']) {
+      containers_+: {},
+    },
     Container+: $.typedNamedArrays(['env', ['ports', v.ContainerPort], 'volumeMounts']),
     ContainerPort+: {
       containerPort: error 'must set containerPort',