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/docker/docker.go

@@ -35,6 +35,20 @@ type Config map[string]interface{}
 
 var _ engine.Interface = (*Config)(nil)
 
+type dockerRuntime map[string]interface{}
+
+var _ engine.RuntimeConfig = (*dockerRuntime)(nil)
+
+// GetBinaryPath retrieves the path to the actual low-level runtime binary invoked by the runtime handler
+func (d dockerRuntime) GetBinaryPath() string {
+	if d == nil {
+		return ""
+	}
+
+	path, _ := d["path"].(string)
+	return path
+}
+
 // New creates a docker config with the specified options
 func New(opts ...Option) (engine.Interface, error) {
 	b := &builder{}
@@ -132,3 +146,22 @@ func (c Config) Save(path string) (int64, error) {
 	n, err := config.Raw(path).Write(output)
 	return int64(n), err
 }
+
+// GetRuntimeConfig returns the runtime info of the runtime passed as input
+func (c *Config) GetRuntimeConfig(name string) (engine.RuntimeConfig, error) {
+	if c == nil {
+		return nil, fmt.Errorf("config is nil")
+	}
+
+	cfg := *c
+
+	var runtimes map[string]interface{}
+	if _, ok := cfg["runtimes"]; ok {
+		runtimes = cfg["runtimes"].(map[string]interface{})
+		if r, ok := runtimes[name]; ok {
+			dr := dockerRuntime(r.(map[string]interface{}))
+			return &dr, nil
+		}
+	}
+	return &dockerRuntime{}, nil
+}

pkg/config/engine/docker/docker_test.go

@@ -213,3 +213,37 @@ func TestUpdateConfigRuntimes(t *testing.T) {
 
 	}
 }
+
+func TestGetRuntimeConfig(t *testing.T) {
+	c := map[string]interface{}{
+		"runtimes": map[string]interface{}{
+			"nvidia": map[string]interface{}{
+				"path": "nvidia-container-runtime",
+				"args": []string{},
+			},
+		},
+	}
+	cfg := Config(c)
+
+	testCases := []struct {
+		description string
+		runtime     string
+		expected    string
+	}{
+		{
+			description: "existing runtime",
+			runtime:     "nvidia",
+			expected:    "nvidia-container-runtime",
+		},
+		{
+			description: "non-existent runtime",
+			runtime:     "some-other-runtime",
+			expected:    "",
+		},
+	}
+	for _, tc := range testCases {
+		rc, err := cfg.GetRuntimeConfig(tc.runtime)
+		require.NoError(t, err)
+		require.Equal(t, tc.expected, rc.GetBinaryPath())
+	}
+}