[WIP] ✨ Generation of typed apply clients using upstream generator

cmd/controller-gen/main.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"sigs.k8s.io/controller-tools/pkg/applyconfigurations"
 	"sigs.k8s.io/controller-tools/pkg/crd"
 	"sigs.k8s.io/controller-tools/pkg/deepcopy"
 	"sigs.k8s.io/controller-tools/pkg/genall"
@@ -51,6 +52,7 @@ var (
 		"crd":         crd.Generator{},
 		"rbac":        rbac.Generator{},
 		"object":      deepcopy.Generator{},
+		"apply":       applyconfigurations.Generator{},
 		"webhook":     webhook.Generator{},
 		"schemapatch": schemapatcher.Generator{},
 	}
@@ -139,13 +141,18 @@ func main() {
 	controller-gen object paths=./apis/v1beta1/some_types.go
 
 	# Generate OpenAPI v3 schemas for API packages and merge them into existing CRD manifests
-	controller-gen schemapatch:manifests=./manifests output:dir=./manifests paths=./pkg/apis/... 
+	controller-gen schemapatch:manifests=./manifests output:dir=./manifests paths=./pkg/apis/...
 
 	# Run all the generators for a given project
 	controller-gen paths=./apis/...
 
 	# Explain the markers for generating CRDs, and their arguments
 	controller-gen crd -ww
+
+	# Generate applyconfigurations for CRDs for use with Server Side Apply. They will be placed
+	# into a "applyconfiguration/" subdirectory
+
+	controller-gen apply paths=./apis/...
 `,
 		RunE: func(c *cobra.Command, rawOpts []string) error {
 			// print version if asked for it

go.mod

@@ -16,16 +16,25 @@ require (
 	k8s.io/api v0.28.0
 	k8s.io/apiextensions-apiserver v0.28.0
 	k8s.io/apimachinery v0.28.0
+	k8s.io/code-generator v0.28.0
+	k8s.io/gengo v0.0.0-20220902162205-c0856e24416d
 	sigs.k8s.io/yaml v1.3.0
 )
 
 require (
 	github.com/fsnotify/fsnotify v1.6.0 // indirect
 	github.com/go-logr/logr v1.2.4 // indirect
+	github.com/go-openapi/jsonpointer v0.19.6 // indirect
+	github.com/go-openapi/jsonreference v0.20.2 // indirect
+	github.com/go-openapi/swag v0.22.3 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/google/gnostic-models v0.6.8 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.17 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
@@ -35,9 +44,11 @@ require (
 	golang.org/x/net v0.15.0 // indirect
 	golang.org/x/sys v0.12.0 // indirect
 	golang.org/x/text v0.13.0 // indirect
+	google.golang.org/protobuf v1.30.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 	k8s.io/klog/v2 v2.100.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9 // indirect
 	k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect

go.sum

@@ -1,4 +1,5 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -8,9 +9,16 @@ github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMo
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4HY=
 github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw=
+github.com/go-logr/logr v0.2.0/go.mod h1:z6/tIYblkpsD+a4lm/fGIIU9mZ+XfAiaFtq7xTgseGU=
 github.com/go-logr/logr v1.2.0/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/go-logr/logr v1.2.4 h1:g01GSCwiDw2xSZfjJ2/T9M+S6pFdcNtFYsp+Y43HYDQ=
 github.com/go-logr/logr v1.2.4/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-openapi/jsonpointer v0.19.6 h1:eCs3fxoIi3Wh6vtgmLTOjdhSpiqphQ+DaPn38N2ZdrE=
+github.com/go-openapi/jsonpointer v0.19.6/go.mod h1:osyAmYz/mB/C3I+WsTTSgw1ONzaLJoLCyoi6/zppojs=
+github.com/go-openapi/jsonreference v0.20.2 h1:3sVjiK66+uXK/6oQ8xgcRKcFgQ5KXa2KvnJRumpMGbE=
+github.com/go-openapi/jsonreference v0.20.2/go.mod h1:Bl1zwGIM8/wsvqjsOQLJ/SH+En5Ap4rVB5KVcIDZG2k=
+github.com/go-openapi/swag v0.22.3 h1:yMBqmnQ0gyZvEb/+KzuWZOXgllrXT4SADYbvDaXHv/g=
+github.com/go-openapi/swag v0.22.3/go.mod h1:UzaqsxGiab7freDnrUUra0MwWfN/q7tE4j+VcZ0yl14=
 github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0/go.mod h1:fyg7847qk6SyHyPtNmDHnmrv/HOrqktSC+C9fM+CJOE=
 github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 h1:tfuBGBXKqDEevZMzYi5KSi8KkcZtzBcTgAUUtapy0OI=
 github.com/gobuffalo/flect v1.0.2 h1:eqjPGSo2WmjgY2XlpGwo2NXgL3RucAKo4k4qQMNA5sA=
@@ -24,25 +32,40 @@ github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrU
 github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
+github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/google/gnostic-models v0.6.8 h1:yo/ABAfM5IMRsS1VnXjTBvUb61tFIHozhlYvRgGre9I=
+github.com/google/gnostic-models v0.6.8/go.mod h1:5n7qKqH0f5wFt+aWF8CW6pZLLNOfYuF5OpfBSENuI8U=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/gofuzz v1.1.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
 github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 h1:K6RDEckDVWvDI9JAJYCmNdQXq6neHJOYx3V6jnqNEec=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/kr/pretty v0.2.0/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
+github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
@@ -123,6 +146,7 @@ golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
 golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20200505023115-26f46d2f7ef8/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20201224043029-2b0845dc783e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
@@ -138,9 +162,14 @@ google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQ
 google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
+google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
+google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/inf.v0 v0.9.1 h1:73M5CoZyi3ZLMOyDlQh031Cx6N9NDJ2Vvfl76EDAgDc=
 gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
@@ -161,13 +190,21 @@ k8s.io/apiextensions-apiserver v0.28.0 h1:CszgmBL8CizEnj4sj7/PtLGey6Na3YgWyGCPON
 k8s.io/apiextensions-apiserver v0.28.0/go.mod h1:uRdYiwIuu0SyqJKriKmqEN2jThIJPhVmOWETm8ud1VE=
 k8s.io/apimachinery v0.28.0 h1:ScHS2AG16UlYWk63r46oU3D5y54T53cVI5mMJwwqFNA=
 k8s.io/apimachinery v0.28.0/go.mod h1:X0xh/chESs2hP9koe+SdIAcXWcQ+RM5hy0ZynB+yEvw=
+k8s.io/code-generator v0.28.0 h1:msdkRVJNVFgdiIJ8REl/d3cZsMB9HByFcWMmn13NyuE=
+k8s.io/code-generator v0.28.0/go.mod h1:ueeSJZJ61NHBa0ccWLey6mwawum25vX61nRZ6WOzN9A=
+k8s.io/gengo v0.0.0-20220902162205-c0856e24416d h1:U9tB195lKdzwqicbJvyJeOXV7Klv+wNAWENRnXEGi08=
+k8s.io/gengo v0.0.0-20220902162205-c0856e24416d/go.mod h1:FiNAH4ZV3gBg2Kwh89tzAEV2be7d5xI0vBa/VySYy3E=
+k8s.io/klog/v2 v2.2.0/go.mod h1:Od+F08eJP+W3HUb4pSrPpgp9DGU4GzlpG/TmITuYh/Y=
 k8s.io/klog/v2 v2.100.1 h1:7WCHKK6K8fNhTqfBhISHQ97KrnJNFZMcQvKp7gP/tmg=
 k8s.io/klog/v2 v2.100.1/go.mod h1:y1WjHnz7Dj687irZUWR/WLkLc5N1YHtjLdmgWjndZn0=
+k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9 h1:LyMgNKD2P8Wn1iAwQU5OhxCKlKJy0sHc+PcDwFB24dQ=
+k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9/go.mod h1:wZK2AVp1uHCp4VamDVgBP2COHZjqD1T68Rf0CM3YjSM=
 k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 h1:qY1Ad8PODbnymg2pRbkyMT/ylpTrCM8P2RJ0yroCyIk=
 k8s.io/utils v0.0.0-20230406110748-d93618cff8a2/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd h1:EDPBXCAspyGV4jQlpZSudPeMmr1bNJefnuqLsRAsHZo=
 sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd/go.mod h1:B8JuhiUyNFVKdsE8h686QcCxMaH6HrOAZj4vswFpcB0=
 sigs.k8s.io/structured-merge-diff/v4 v4.2.3 h1:PRbqxJClWWYMNV1dhaG4NsibJbArud9kFxnAMREiWFE=
 sigs.k8s.io/structured-merge-diff/v4 v4.2.3/go.mod h1:qjx8mGObPmV2aSZepjQjbmb2ihdVs8cGKBraizNC69E=
+sigs.k8s.io/yaml v1.2.0/go.mod h1:yfXDCHCao9+ENCvLSE62v9VSji2MKu5jeNfTrofGhJc=
 sigs.k8s.io/yaml v1.3.0 h1:a2VclLzOGrwOHDiV8EfBGhvjHvP46CtW5j6POvhYGGo=
 sigs.k8s.io/yaml v1.3.0/go.mod h1:GeOyir5tyXNByN85N/dRIT9es5UQNerPYEKK56eTBm8=

pkg/applyconfigurations/applyconfiguration_integration_test.go

@@ -0,0 +1,151 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package applyconfigurations
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"k8s.io/apimachinery/pkg/util/sets"
+
+	"sigs.k8s.io/controller-tools/pkg/crd"
+	"sigs.k8s.io/controller-tools/pkg/genall"
+	"sigs.k8s.io/controller-tools/pkg/loader"
+	"sigs.k8s.io/controller-tools/pkg/markers"
+)
+
+type outputToMap map[string]*outputFile
+
+// Open implements genall.OutputRule.
+func (m outputToMap) Open(_ *loader.Package, path string) (io.WriteCloser, error) {
+	if _, ok := m[path]; !ok {
+		m[path] = &outputFile{}
+	}
+	return m[path], nil
+}
+
+type outputFile struct {
+	contents []byte
+}
+
+func (o *outputFile) Write(p []byte) (int, error) {
+	o.contents = append(o.contents, p...)
+	return len(p), nil
+}
+
+func (o *outputFile) Close() error {
+	return nil
+}
+
+var _ = Describe("CRD Generation From Parsing to CustomResourceDefinition", func() {
+	outputPath := "testapplyconfiguration"
+	masterPath := "applyconfiguration"
+	By("resetting the test directory")
+	// not using after each to allow for inspection of failed tests
+	BeforeEach(func() {
+		Expect(os.RemoveAll(filepath.Join(".", outputPath))).To(Succeed())
+	})
+	It("should be able to verify generated ApplyConfiguration types for the CronJob schema", func() {
+		By("switching into testdata to appease go modules")
+		cwd, err := os.Getwd()
+		Expect(err).NotTo(HaveOccurred())
+		Expect(os.Chdir("./testdata/cronjob")).To(Succeed()) // go modules are directory-sensitive
+		defer func() { Expect(os.Chdir(cwd)).To(Succeed()) }()
+
+		output := make(outputToMap)
+
+		By("initializing the runtime")
+		optionsRegistry := &markers.Registry{}
+		Expect(optionsRegistry.Register(markers.Must(markers.MakeDefinition("crd", markers.DescribesPackage, crd.Generator{})))).To(Succeed())
+		// Add the applyconfigurations generator but set it to verify only.
+		// This allows us to check if there's a diff between the checked in generated data and what it would generate now.
+		Expect(optionsRegistry.Register(markers.Must(markers.MakeDefinition("apply", markers.DescribesPackage, Generator{})))).To(Succeed())
+		rt, err := genall.FromOptions(optionsRegistry, []string{
+			"crd", // Run another generator first to make sure they don't interfere; see also: the comment on cronjob_types.go:UntypedBlob
+			"apply",
+		})
+		Expect(err).NotTo(HaveOccurred())
+		rt.OutputRules = genall.OutputRules{Default: output}
+
+		cronJobFS := os.DirFS(".")
+
+		By("running the generator and checking for errors")
+		hadErrs := rt.Run()
+
+		By("checking for errors")
+		Expect(hadErrs).To(BeFalse(), "Generator should run without errors")
+
+		filesInMaster := make(map[string][]byte)
+		masterFileNames := sets.New[string]()
+		Expect(fs.WalkDir(cronJobFS, masterPath, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if d.IsDir() {
+				return nil
+			}
+
+			data, err := os.ReadFile(path)
+			if err != nil {
+				return fmt.Errorf("error reading file %s: %w", path, err)
+			}
+
+			// Record the path without the path prefix for comparison later.
+			path = strings.TrimPrefix(path, masterPath+"/")
+			masterFileNames.Insert(path)
+			filesInMaster[path] = data
+			return nil
+		})).To(Succeed())
+
+		filesInOutput := make(map[string][]byte)
+		outputFileNames := sets.New[string]()
+		Expect(fs.WalkDir(cronJobFS, outputPath, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if d.IsDir() {
+				return nil
+			}
+
+			data, err := os.ReadFile(path)
+			if err != nil {
+				return fmt.Errorf("error reading file %s: %w", path, err)
+			}
+
+			// Record the path without the path prefix for comparison later.
+			path = strings.TrimPrefix(path, outputPath+"/")
+			outputFileNames.Insert(path)
+			filesInOutput[path] = data
+			return nil
+		})).To(Succeed())
+
+		// Every file should be in both sets, check for files not in both sets.
+		Expect(masterFileNames.SymmetricDifference(outputFileNames).UnsortedList()).To(BeEmpty(), "Generated files should match the checked in files")
+
+		for name, content := range filesInMaster {
+			Expect(string(filesInOutput[name])).To(Equal(string(content)), "Generated files should match the checked in files, diff found in %s", name)
+		}
+	})
+})

pkg/applyconfigurations/applyconfiguration_suite_test.go

@@ -0,0 +1,29 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package applyconfigurations
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestObjectGeneration(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "ApplyConfiguration Generation Suite")
+}

pkg/applyconfigurations/doc.go

@@ -0,0 +1,18 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package applyconfigurations generates types for constructing declarative apply configurations.
+package applyconfigurations