Allow per-runtime config overrides

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

pkg/config/engine/api.go

@@ -19,7 +19,7 @@ package engine
 // Interface defines the API for a runtime config updater.
 type Interface interface {
 	DefaultRuntime() string
-	AddRuntime(string, string, bool) error
+	AddRuntime(string, string, bool, ...map[string]interface{}) error
 	Set(string, interface{})
 	RemoveRuntime(string) error
 	Save(string) (int64, error)

pkg/config/engine/containerd/config_v1.go

@@ -30,7 +30,7 @@ type ConfigV1 Config
 var _ engine.Interface = (*ConfigV1)(nil)
 
 // AddRuntime adds a runtime to the containerd config
-func (c *ConfigV1) AddRuntime(name string, path string, setAsDefault bool) error {
+func (c *ConfigV1) AddRuntime(name string, path string, setAsDefault bool, configOverrides ...map[string]interface{}) error {
 	if c == nil || c.Tree == nil {
 		return fmt.Errorf("config is nil")
 	}
@@ -75,6 +75,16 @@ func (c *ConfigV1) AddRuntime(name string, path string, setAsDefault bool) error
 		}
 		config.SetPath([]string{"plugins", "cri", "containerd", "default_runtime", "options", "BinaryName"}, path)
 		config.SetPath([]string{"plugins", "cri", "containerd", "default_runtime", "options", "Runtime"}, path)
+
+		defaultRuntimeSubtree := subtreeAtPath(config, "plugins", "cri", "containerd", "default_runtime")
+		if err := defaultRuntimeSubtree.applyOverrides(configOverrides...); err != nil {
+			return fmt.Errorf("failed to apply config overrides to default_runtime: %w", err)
+		}
+	}
+
+	runtimeSubtree := subtreeAtPath(config, "plugins", "cri", "containerd", "runtimes", name)
+	if err := runtimeSubtree.applyOverrides(configOverrides...); err != nil {
+		return fmt.Errorf("failed to apply config overrides: %w", err)
 	}
 
 	*c.Tree = config

pkg/config/engine/containerd/config_v2.go

@@ -25,7 +25,7 @@ import (
 )
 
 // AddRuntime adds a runtime to the containerd config
-func (c *Config) AddRuntime(name string, path string, setAsDefault bool) error {
+func (c *Config) AddRuntime(name string, path string, setAsDefault bool, configOverrides ...map[string]interface{}) error {
 	if c == nil || c.Tree == nil {
 		return fmt.Errorf("config is nil")
 	}
@@ -60,6 +60,11 @@ func (c *Config) AddRuntime(name string, path string, setAsDefault bool) error {
 		config.SetPath([]string{"plugins", "io.containerd.grpc.v1.cri", "containerd", "default_runtime_name"}, name)
 	}
 
+	runtimeSubtree := subtreeAtPath(config, "plugins", "io.containerd.grpc.v1.cri", "containerd", "runtimes", name)
+	if err := runtimeSubtree.applyOverrides(configOverrides...); err != nil {
+		return fmt.Errorf("failed to apply config overrides: %w", err)
+	}
+
 	*c.Tree = config
 	return nil
 }

pkg/config/engine/containerd/config_v2_test.go

@@ -0,0 +1,97 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package containerd
+
+import (
+	"testing"
+
+	"github.com/pelletier/go-toml"
+	"github.com/stretchr/testify/require"
+)
+
+func TestAddRuntime(t *testing.T) {
+	testCases := []struct {
+		description     string
+		config          string
+		setAsDefault    bool
+		configOverrides []map[string]interface{}
+		expectedConfig  string
+		expectedError   error
+	}{
+		{
+			description: "empty config not default runtime",
+			expectedConfig: `
+			version = 2
+			[plugins]
+			[plugins."io.containerd.grpc.v1.cri"]
+				[plugins."io.containerd.grpc.v1.cri".containerd]
+				[plugins."io.containerd.grpc.v1.cri".containerd.runtimes]
+					[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test]
+					privileged_without_host_devices = false
+					runtime_engine = ""
+					runtime_root = ""
+					runtime_type = ""
+					[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test.options]
+						BinaryName = "/usr/bin/test"
+			`,
+			expectedError: nil,
+		},
+		{
+			description: "empty config not default runtime with overrides",
+			configOverrides: []map[string]interface{}{
+				{
+					"options": map[string]interface{}{
+						"SystemdCgroup": true,
+					},
+				},
+			},
+			expectedConfig: `
+			version = 2
+			[plugins]
+			[plugins."io.containerd.grpc.v1.cri"]
+				[plugins."io.containerd.grpc.v1.cri".containerd]
+				[plugins."io.containerd.grpc.v1.cri".containerd.runtimes]
+					[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test]
+					privileged_without_host_devices = false
+					runtime_engine = ""
+					runtime_root = ""
+					runtime_type = ""
+					[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test.options]
+						BinaryName = "/usr/bin/test"
+						SystemdCgroup = true
+			`,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			config, err := toml.Load(tc.config)
+			require.NoError(t, err)
+			expectedConfig, err := toml.Load(tc.expectedConfig)
+			require.NoError(t, err)
+
+			c := &Config{
+				Tree: config,
+			}
+
+			err = c.AddRuntime("test", "/usr/bin/test", tc.setAsDefault, tc.configOverrides...)
+			require.NoError(t, err)
+
+			require.EqualValues(t, expectedConfig.String(), config.String())
+		})
+	}
+}

pkg/config/engine/containerd/toml.go

@@ -0,0 +1,56 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package containerd
+
+import (
+	"fmt"
+
+	"github.com/pelletier/go-toml"
+)
+
+// tomlTree is an alias for toml.Tree that allows for extensions.
+type tomlTree toml.Tree
+
+func subtreeAtPath(c toml.Tree, path ...string) *tomlTree {
+	tree := c.GetPath(path).(*toml.Tree)
+	return (*tomlTree)(tree)
+}
+
+func (t *tomlTree) insert(other map[string]interface{}) error {
+
+	for key, value := range other {
+		if insertsubtree, ok := value.(map[string]interface{}); ok {
+			subtree := (*toml.Tree)(t).Get(key).(*toml.Tree)
+			return (*tomlTree)(subtree).insert(insertsubtree)
+		}
+		(*toml.Tree)(t).Set(key, value)
+	}
+	return nil
+}
+
+func (t *tomlTree) applyOverrides(overrides ...map[string]interface{}) error {
+	for _, override := range overrides {
+		subconfig, err := toml.TreeFromMap(override)
+		if err != nil {
+			return fmt.Errorf("invalid toml config: %w", err)
+		}
+		if err := t.insert(subconfig.ToMap()); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/config/engine/crio/crio.go

@@ -40,7 +40,7 @@ func New(opts ...Option) (engine.Interface, error) {
 }
 
 // AddRuntime adds a new runtime to the crio config
-func (c *Config) AddRuntime(name string, path string, setAsDefault bool) error {
+func (c *Config) AddRuntime(name string, path string, setAsDefault bool, _ ...map[string]interface{}) error {
 	if c == nil {
 		return fmt.Errorf("config is nil")
 	}

pkg/config/engine/docker/docker.go

@@ -49,7 +49,7 @@ func New(opts ...Option) (engine.Interface, error) {
 }
 
 // AddRuntime adds a new runtime to the docker config
-func (c *Config) AddRuntime(name string, path string, setAsDefault bool) error {
+func (c *Config) AddRuntime(name string, path string, setAsDefault bool, _ ...map[string]interface{}) error {
 	if c == nil {
 		return fmt.Errorf("config is nil")
 	}