Add clustersim command for manual MCM testing

.gitignore

@@ -6,7 +6,6 @@
 /test
 /logs
 /hack/tools/bin
-/pkg/simulatedprovider/bin
 
 *.html
 .vscode

pkg/simulatedprovider/.gitignore

@@ -0,0 +1,3 @@
+# Default command output directory
+/gen
+/bin

pkg/simulatedprovider/Makefile

@@ -13,7 +13,6 @@ KWOK_VERSION  ?= v0.8.0
 $(KWOKCTL): $(TOOLS_BIN_DIR)
 	GOBIN=$(abspath $(TOOLS_BIN_DIR)) go install sigs.k8s.io/kwok/cmd/{kwok,kwokctl}@$(KWOK_VERSION)
 
-
 .PHONY: build
 build:
 	@mkdir -p bin
@@ -47,3 +46,8 @@ stop-simulated-cluster: $(KWOKCTL)
 .PHONY: test-integration
 test-integration:
 	@(cd test/integration/controller; ginkgo -v --show-node-events --poll-progress-after=300s --poll-progress-interval=60s)
+
+.PHONY: build-clustersim
+build-clustersim:
+	@mkdir -p bin
+	go build -v -o bin/clustersim ./cmd/clustersim

pkg/simulatedprovider/cmd/clustersim/.gitignore

@@ -0,0 +1,5 @@
+# Default command output directory
+/gen
+
+# Command binary
+clustersim

pkg/simulatedprovider/cmd/clustersim/README.md

@@ -0,0 +1,130 @@
+## Clustersim
+
+It is a tool that can be used for manual MCM testing, allowing a developer to create an environment where they can deploy custom `MachineClass`es and `MachineDeployment`s in a virtual environment running both the MCM and the simulated provider processes.
+
+The command line program contains a bunch of helper sub-commands allowing one to set-up the cluster in numerous ways before they actually run any processes.
+
+### `help`
+
+```
+./bin/clustersim -h
+Manages and sets up virtual cluster running simulated Machine Controller Manager.
+
+Usage:
+clustersim {--clusters name}... command [--dir /tmp]
+clustersim [command]
+
+Examples:
+clustersim --clusters "test" setup
+
+Available Commands:
+build       Builds the specified components (machine-controller-manager, simulated provider).
+completion  Generate the autocompletion script for the specified shell
+copyshoot   Fetches MachineDeployments and MachineClasses from specified shoot.
+gencluster  Generates MachineClasses and MachineDeployments with the specified parameters.
+help        Help about any command
+setup       Generates the launch configuration for the cluster components.
+start       Creates kwok cluster and starts specified components using their launch config.
+stop        Stops specified components using their pid and destroys the kwok cluster.
+
+Flags:
+--clusters strings   comma separated list of cluster(s) to target (required)
+--dir string         optional flag to specify the directory for clusters data (default "./gen")
+-h, --help               help for clustersim
+```
+
+The main command takes two flags, one optional and one required.
+- The flag to specify clusters' data directory is optional, and if unspecified falls back to `./gen` directory.
+- The flag to list out the cluster names is required by all subcommands except the `build` command.
+
+### `build`
+
+Builds the specified components, fallsback to building both `machine-controller-manager` and the `simulated-provider` if unspecifed. Requires a mandatory flag `source-dir` pointing to the `machine-controller-manager` source root directory.
+
+```
+./bin/clustersim build -h
+Builds the specified components (machine-controller-manager, simulated provider).
+
+Usage:
+clustersim build {--source-dir ..} [--components mcm]...
+
+Examples:
+clustersim build --source-dir ../../../../ --components "mcm,mc"
+
+Flags:
+-c, --components strings   comma separated list of components to build (default [mcm,mc])
+-h, --help                 help for build
+--source-dir string    machine-controller-manager source root directory path (required)
+```
+
+### `setup`
+
+Generates the launch configuration for the cluster components. **Requires** the `mcc.yaml` and the `mcd.yaml` files to already be present in the specified clusters' directories. These can be manually fetched by targeting a cluster or be constructed via the `gencluster` subcommand.
+
+The launch configuration consists of the path for the components binaries and their corresponding launch flags.
+
+### `copyshoot`
+
+Rather than manually fetching the data for a cluster for `setup`, `clustersim` also provides a gardener shoot specific `copyshoot` subcommand which can fetch the `MachineClass`es and `MachineDeployment`s of a live cluster in an automated fashion provided the user has the required permission to access the specified shoot's data.
+
+It can also fetch the launch flags for the components from the actual cluster as well, and sanitizes the flags for the virtual cluster's usage.
+
+```
+./bin/clustersim copyshoot -h
+Fetches MachineDeployments and MachineClasses from specified shoot.
+
+Usage:
+clustersim copyshoot {--clusters name} {-l landscape} {-p project} {-s shoot} [-f true|false]
+
+Flags:
+-f, --fetch-config       fetch component configuration from cluster (default true)
+-h, --help               help for copyshoot
+-l, --landscape string   gardener landscape name (required)
+-p, --project string     gardener project name (required)
+-s, --shoot string       gardener shoot name (required)
+```
+
+### `gencluster`
+
+In case a developer needs to quickly generate some dummy data for testing, a `gencluster` helper command is provided, which takes specified `zones` and `instances` and constructs MCCs and MCDs for their cross-product. Additionally it generates the required launch configuration as well.
+
+```
+./bin/clustersim gencluster -h
+Generates MachineClasses and MachineDeployments with the specified parameters.
+
+Usage:
+clustersim gencluster {--clusters name} {--zones zone}... {--instances inst}...
+
+Flags:
+-h, --help                help for gencluster
+-i, --instances strings   comma separated list of instances to use (required)
+-z, --zones strings       comma separated list of zones to use (required)
+```
+
+It utilizes the templates present in [./templates](./templates) in order to construct the required mcc and mcd. And uses the data present in [./templates/instances.json](./templates/instances.json) to get the required `arch` and the `capacity` for the specified instances.
+
+### `start`
+
+This runs the actual virtual cluster and deploys the MCC and MCD belonging to the clusters, it also creates two files per component that it runs (mcm, machine-controller):
+- `<process>.pid`: denoting the PID for the component, used by the `stop` command to kill the process for the specified cluster.
+- `<process>.log`: consisting of the components' log file.
+
+### `stop`
+
+Kills the specified clusters' specified components and destroys the virtual cluster.
+
+```
+./bin/clustersim stop -h
+Stops specified components using their pid and destroys the kwok cluster.
+
+Usage:
+clustersim stop {--clusters name}... [--components mcm]... [--killall true|false]
+
+Examples:
+clustersim --clusters "test" stop
+
+Flags:
+-c, --components strings   comma separated list of components to stop (default [mcm,mc])
+-h, --help                 help for stop
+--killall              stop all components and destroy all clusters (default true)
+```

pkg/simulatedprovider/cmd/clustersim/build.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"slices"
+
+	"github.com/spf13/cobra"
+)
+
+type BuildFlags struct {
+	SourceDir  string
+	Components []string
+}
+
+var buildFlags BuildFlags
+
+const (
+	mcmCmdFile      = "cmd/machine-controller-manager/controller_manager.go"
+	providerCmdFile = "cmd/machine-controller/main.go"
+)
+
+var buildCmd = &cobra.Command{
+	Use:                   "build {--source-dir ..} [--components mcm]...",
+	Short:                 "Builds the specified components (machine-controller-manager, simulated provider).",
+	Example:               `clustersim build --source-dir ../../../../ --components "mcm,mc"`,
+	DisableFlagsInUseLine: true,
+	PreRunE: func(cmd *cobra.Command, _ []string) error {
+		if buildFlags.SourceDir == "" {
+			return fmt.Errorf("required flag --source-dir not passed")
+		}
+
+		if err := validateComponents(buildFlags.Components); err != nil {
+			return err
+		}
+
+		binDir := filepath.Join(getClustersDir(cmd), "bin")
+		return os.MkdirAll(binDir, 0750)
+	},
+	RunE: func(cmd *cobra.Command, _ []string) error {
+		cmd.SilenceUsage = true
+
+		ctx := cmd.Context()
+		binDir := filepath.Join(getClustersDir(cmd), "bin")
+
+		if slices.Contains(buildFlags.Components, componentMCM) {
+			outputPath := filepath.Join(binDir, binaryNameMCM)
+			err := goBuild(ctx, buildFlags.SourceDir, mcmCmdFile, outputPath)
+			if err != nil {
+				return err
+			}
+		}
+
+		if slices.Contains(buildFlags.Components, componentMC) {
+			providerPkgPath, err := getProviderRoot(buildFlags.SourceDir)
+			if err != nil {
+				return err
+			}
+
+			outputPath := filepath.Join(binDir, binaryNameMC)
+			err = goBuild(ctx, providerPkgPath, providerCmdFile, outputPath)
+			if err != nil {
+				return err
+			}
+		}
+		return nil
+	},
+}
+
+func init() {
+	buildCmd.PersistentFlags().StringSliceVarP(
+		&buildFlags.Components, "components", "c", allComponents,
+		"comma separated list of components to build",
+	)
+	buildCmd.PersistentFlags().StringVar(
+		&buildFlags.SourceDir, "source-dir", "",
+		"machine-controller-manager source root directory path (required)",
+	)
+}
+
+// goBuild invokes `go build -C dir -o binPath -v -buildvcs=true file`
+func goBuild(ctx context.Context, dir, file, binPath string) error {
+	binPathAbs, err := filepath.Abs(binPath)
+	if err != nil {
+		return fmt.Errorf("cannot get absolute path for path %q: %w", binPath, err)
+	}
+
+	fmt.Printf("Building %q\n", binPath)
+	cmd := exec.CommandContext(
+		ctx, "go", "build", "-C", dir, "-o", binPathAbs, "-v", "-buildvcs=true", file,
+	)
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	err = cmd.Run()
+	if err != nil {
+		return err
+	}
+
+	if finfo, err := os.Stat(binPath); err != nil && finfo.IsDir() {
+		return fmt.Errorf("did not find binary installed at expected path %q", binPath)
+	}
+
+	return nil
+}
+
+func getProviderRoot(sourceDir string) (string, error) {
+	return filepath.Abs(filepath.Join(sourceDir, "pkg", "simulatedprovider"))
+}