Use code-generation for CRD API and deepcopy methods (#369)

Client-go provides a https://github.com/kubernetes/code-generator package in order to provide the API to work with CRDs similar to the one available for built-in types, i.e. Pods, Statefulsets and so on.

Use this package to generate deepcopy methods (required for CRDs), instead of using an external deepcopy package; we also generate APIs used to manipulate both Postgres and OperatorConfiguration CRDs, as well as informers and listers for the Postgres CRD, instead of using generic informers and CRD REST API; by using generated code we can get rid of some custom and obscure CRD-related code and use a better API.

All generated code resides in /pkg/generated, with an exception of zz_deepcopy.go in apis/acid.zalan.do/v1

Rename postgres-operator-configuration CRD to OperatorConfiguration, since the former broke naming convention in the code-generator.

Moved Postgresql, PostgresqlList, OperatorConfiguration and OperatorConfigurationList and other types used by them into

Change the type of  the Error field in the Postgresql crd to a string, so that client-go could generate a deepcopy for it.

Use generated code to set status of CRD objects as well. Right now this is done with patch, however, Kubernetes 1.11 introduces the /status subresources, allowing us to set the status with
the special updateStatus call in the future. For now, we keep the code that is compatible with earlier versions of Kubernetes.

Rename postgresql.go to database.go and status.go to logs_and_api.go to reflect the purpose of each of those files.

Update client-go dependencies.

Minor reformatting and renaming.

hack/custom-boilerplate.go.txt

@@ -0,0 +1,21 @@
+/*
+Copyright YEAR Compose, Zalando SE
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/

hack/update-codegen.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+SCRIPT_ROOT=$(dirname ${BASH_SOURCE})/..
+CODEGEN_PKG=${CODEGEN_PKG:-$(cd ${SCRIPT_ROOT}; ls -d -1 ./vendor/k8s.io/code-generator 2>/dev/null || echo ${GOPATH}/src/k8s.io/code-generator)}
+
+vendor/k8s.io/code-generator/generate-groups.sh all \
+  github.com/zalando-incubator/postgres-operator/pkg/generated github.com/zalando-incubator/postgres-operator/pkg/apis \
+  acid.zalan.do:v1 \
+  --go-header-file ${SCRIPT_ROOT}/hack/custom-boilerplate.go.txt

hack/verify-codegen.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+SCRIPT_ROOT=$(dirname "${BASH_SOURCE}")/..
+DIFFROOT="${SCRIPT_ROOT}/pkg"
+TMP_DIFFROOT="${SCRIPT_ROOT}/_tmp/pkg"
+_tmp="${SCRIPT_ROOT}/_tmp"
+
+cleanup() {
+    rm -rf "${_tmp}"
+}
+trap "cleanup" EXIT SIGINT
+
+cleanup
+
+mkdir -p "${TMP_DIFFROOT}"
+cp -a "${DIFFROOT}"/* "${TMP_DIFFROOT}"
+
+"${SCRIPT_ROOT}/hack/update-codegen.sh"
+echo "diffing ${DIFFROOT} against freshly generated codegen"
+ret=0
+diff -Naupr "${DIFFROOT}" "${TMP_DIFFROOT}" || ret=$?
+cp -a "${TMP_DIFFROOT}"/* "${DIFFROOT}"
+if [[ $ret -eq 0 ]]
+then
+    echo "${DIFFROOT} up to date."
+else
+    echo "${DIFFROOT} is out of date. Please run hack/update-codegen.sh"
+    exit 1
+fi