fetch current container runtime config through the command line

Signed-off-by: Tariq Ibrahim <tibrahim@nvidia.com>

add default runtime binary path to runtimes field of toolkit config toml

Signed-off-by: Tariq Ibrahim <tibrahim@nvidia.com>

[no-relnote] Get low-level runtimes consistently

We ensure that we use the same low-level runtimes regardless
of the runtime engine being configured. This ensures consistent
behaviour.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

Co-authored-by: Evan Lezar <elezar@nvidia.com>

address review comment

Signed-off-by: Tariq Ibrahim <tibrahim@nvidia.com>

pkg/config/engine/crio/crio.go

@@ -30,6 +30,22 @@ type Config struct {
 	Logger logger.Interface
 }
 
+type crioRuntime struct {
+	tree *toml.Tree
+}
+
+var _ engine.RuntimeConfig = (*crioRuntime)(nil)
+
+// GetBinaryPath retrieves the path to the actual low-level runtime binary invoked by the runtime handler
+func (c *crioRuntime) GetBinaryPath() string {
+	if c.tree != nil {
+		if binaryPath, ok := c.tree.GetPath([]string{"runtime_path"}).(string); ok {
+			return binaryPath
+		}
+	}
+	return ""
+}
+
 var _ engine.Interface = (*Config)(nil)
 
 // New creates a cri-o config with the specified options
@@ -65,11 +81,7 @@ func (c *Config) AddRuntime(name string, path string, setAsDefault bool) error {
 
 	config := *c.Tree
 
-	// By default we extract the runtime options from the runc settings; if this does not exist we get the options from the default runtime specified in the config.
-	runtimeNamesForConfig := []string{"runc"}
-	if name, ok := config.GetPath([]string{"crio", "runtime", "default_runtime"}).(string); ok && name != "" {
-		runtimeNamesForConfig = append(runtimeNamesForConfig, name)
-	}
+	runtimeNamesForConfig := engine.GetLowLevelRuntimes(c)
 	for _, r := range runtimeNamesForConfig {
 		if options, ok := config.GetPath([]string{"crio", "runtime", "runtimes", r}).(*toml.Tree); ok {
 			c.Logger.Debugf("using options from runtime %v: %v", r, options.String())
@@ -129,3 +141,27 @@ func (c *Config) RemoveRuntime(name string) error {
 	*c.Tree = config
 	return nil
 }
+
+func (c *Config) GetRuntimeConfig(name string) (engine.RuntimeConfig, error) {
+	if c == nil || c.Tree == nil {
+		return nil, fmt.Errorf("config is nil")
+	}
+	runtimeData := c.GetSubtreeByPath([]string{"crio", "runtime", "runtimes", name})
+	return &crioRuntime{
+		tree: runtimeData,
+	}, nil
+}
+
+// CommandLineSource returns the CLI-based crio config loader
+func CommandLineSource(hostRoot string) toml.Loader {
+	commandLine := chrootIfRequired(hostRoot, "crio", "status", "config")
+	return toml.FromCommandLine(commandLine[0], commandLine[1:]...)
+}
+
+func chrootIfRequired(hostRoot string, commandLine ...string) []string {
+	if hostRoot == "" || hostRoot == "/" {
+		return commandLine
+	}
+
+	return append([]string{"chroot", hostRoot}, commandLine...)
+}

pkg/config/engine/crio/crio_test.go

@@ -91,7 +91,7 @@ func TestAddRuntime(t *testing.T) {
 			`,
 		},
 		{
-			description: "options from runc take precedence over default runtime",
+			description: "options from the default runtime take precedence over runc",
 			config: `
 			[crio]
 			[crio.runtime]
@@ -120,7 +120,7 @@ func TestAddRuntime(t *testing.T) {
 			[crio.runtime.runtimes.test]
 			runtime_path = "/usr/bin/test"
 			runtime_type = "oci"
-			runc_option = "option"
+			default_option = "option"
 			`,
 		},
 	}
@@ -144,3 +144,61 @@ func TestAddRuntime(t *testing.T) {
 		})
 	}
 }
+
+func TestGetRuntimeConfig(t *testing.T) {
+	logger, _ := testlog.NewNullLogger()
+	config := `
+[crio.image]
+signature_policy = "/etc/crio/policy.json"
+
+[crio.runtime]
+default_runtime = "crun"
+
+[crio.runtime.runtimes.crun]
+runtime_path = "/usr/libexec/crio/crun"
+runtime_root = "/run/crun"
+monitor_path = "/usr/libexec/crio/conmon"
+allowed_annotations = [
+    "io.containers.trace-syscall",
+]
+
+[crio.runtime.runtimes.runc]
+runtime_path = "/usr/libexec/crio/runc"
+runtime_root = "/run/runc"
+monitor_path = "/usr/libexec/crio/conmon"
+`
+	testCases := []struct {
+		description   string
+		runtime       string
+		expected      string
+		expectedError error
+	}{
+		{
+			description:   "valid runtime config, existing runtime",
+			runtime:       "crun",
+			expected:      "/usr/libexec/crio/crun",
+			expectedError: nil,
+		},
+		{
+			description:   "valid runtime config, non-existing runtime",
+			runtime:       "some-other-runtime",
+			expected:      "",
+			expectedError: nil,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			cfg, err := toml.Load(config)
+			require.NoError(t, err)
+
+			c := &Config{
+				Logger: logger,
+				Tree:   cfg,
+			}
+
+			rc, err := c.GetRuntimeConfig(tc.runtime)
+			require.Equal(t, tc.expectedError, err)
+			require.Equal(t, tc.expected, rc.GetBinaryPath())
+		})
+	}
+}