Add doc about running debug directly from assisted-service container

Allow us to debug code directly from assisted-service container.

docs/dev/debug_delve.md

@@ -0,0 +1,91 @@
+
+# assisted-service runs on minikube
+
+## Debug Setup
+
+To debug assisted-service directly from minikube container
+Install minikube setup with assisted-service with one replica
+
+```shell
+export KUBECONFIG=source /root/.kube/config
+kubectl patch deployment assisted-service -n assisted-installer --type json -p="[{\"op\": \"remove\", \"path\": \"/spec/template/spec/containers/0/livenessProbe\"}]"
+kubectl patch deployment assisted-service -n assisted-installer --type json -p="[{\"op\": \"remove\", \"path\": \"/spec/template/spec/containers/0/readinessProbe\"}]"
+oc rollout restart deployment -n assisted-installer assisted-service
+```
+
+Login to minikube node and attach to assisted-service container
+
+```shell
+oc rsh -n assisted-installer [pod/assisted-service-name] 
+# install packages git goland and telnet
+dnf install procps psmisc golang delve iproute iputils telnet net-tools git -y
+```
+
+Before running dlv attach make sure assisted-service sources exists
+
+```shell
+git clone https://github.com/openshift/assisted-service.git
+# git checkout to the same minikube assisted-service version/tag
+```
+After dlv attach we can break by func name or filepath:line
+Trigger event from UI, test-infra or others till hit on requested break
+
+Example for dlv attach to pid 1 (assisted-service)
+
+```shell
+dlv attach 1 
+
+(dlv) b /assisted-service/internal/bminventory/inventory.go:759
+Breakpoint 1 set at 0x380418e for github.com/openshift/assisted-service/internal/bminventory.verifyMinimalOpenShiftVersionForSingleNode() ./internal/bminventory/inventory.go:759
+(dlv) c
+
+> github.com/openshift/assisted-service/internal/bminventory.verifyMinimalOpenShiftVersionForSingleNode() ./internal/bminventory/inventory.go:759 (hits goroutine(45458):1 total:1) (PC: 0x380418e)
+Warning: debugging optimized function
+Warning: listing may not match stale executable
+   756:	
+   757:	func verifyMinimalOpenShiftVersionForSingleNode(requestedOpenshiftVersion string) error {
+   758:		ocpVersion, err := version.NewVersion(requestedOpenshiftVersion)
+=> 759:		if err != nil {
+   760:			return errors.Errorf("Failed to parse OCP version %s", requestedOpenshiftVersion)
+   761:		}
+   762:		minimalVersionForSno, err := version.NewVersion(minimalOpenShiftVersionForSingleNode)
+   763:		if err != nil {
+   764:			return errors.Errorf("Failed to parse minimal OCP version %s", minimalOpenShiftVersionForSingleNode)
+   765:		}
+   766:		if ocpVersion.LessThan(minimalVersionForSno) {
+   767:			return errors.Errorf("Invalid OCP version (%s) for Single node, Single node OpenShift is supported for version 4.8 and above", requestedOpenshiftVersion)
+   768:		}
+   769:		return nil
+
+
+```
+
+When break you can continue step/next/print command (Examples)
+
+```shell
+(dlv) stack
+ 0  0x000000000380418e in github.com/openshift/assisted-service/internal/bminventory.verifyMinimalOpenShiftVersionForSingleNode
+    at ./internal/bminventory/inventory.go:759
+ 1  0x00000000037ffe11 in github.com/openshift/assisted-service/internal/bminventory.(*bareMetalInventory).validateRegisterClusterInternalParams
+    at ./internal/bminventory/inventory.go:399
+ 2  0x00000000038010f7 in github.com/openshift/assisted-service/internal/bminventory.(*bareMetalInventory).RegisterClusterInternal
+    at ./internal/bminventory/inventory.go:541
+ 3  0x000000000383f619 in github.com/openshift/assisted-service/internal/bminventory.(*bareMetalInventory).V2RegisterCluster
+    at ./internal/bminventory/inventory_v2_handlers.go:46
+
+(dlv) locals
+ocpVersion = ("*github.com/hashicorp/go-version.Version")(0xc0013e8cd0)
+err = error nil
+
+
+(dlv) p ocpVersion
+("*github.com/hashicorp/go-version.Version")(0xc0013e8cd0)
+*github.com/hashicorp/go-version.Version {
+	metadata: "",
+	pre: "",
+	segments: []int64 len: 3, cap: 4, [4,15,0],
+	si: 2,
+	original: "4.15",}
+(dlv) whatis ocpVersion
+*github.com/hashicorp/go-version.Versio
+```