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Merge pull request #678 from mccv1r0/pr661
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libcni: add config caching [v2]
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@jellonek
jellonek authored Jul 20, 2019
2 parents 461cf2b + 9af40ed commit df124b2
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Showing 2 changed files with 263 additions and 30 deletions.
147 changes: 133 additions & 14 deletions libcni/api.go
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,10 @@ var (
CacheDir = "/var/lib/cni"
)

const (
CNICacheV1 = "cniCacheV1"
)

// A RuntimeConf holds the arguments to one invocation of a CNI plugin
// excepting the network configuration, with the nested exception that
// the `runtimeConfig` from the network configuration is included
Expand Down Expand Up @@ -70,11 +74,13 @@ type CNI interface {
CheckNetworkList(ctx context.Context, net *NetworkConfigList, rt *RuntimeConf) error
DelNetworkList(ctx context.Context, net *NetworkConfigList, rt *RuntimeConf) error
GetNetworkListCachedResult(net *NetworkConfigList, rt *RuntimeConf) (types.Result, error)
GetNetworkListCachedConfig(net *NetworkConfigList, rt *RuntimeConf) ([]byte, *RuntimeConf, error)

AddNetwork(ctx context.Context, net *NetworkConfig, rt *RuntimeConf) (types.Result, error)
CheckNetwork(ctx context.Context, net *NetworkConfig, rt *RuntimeConf) error
DelNetwork(ctx context.Context, net *NetworkConfig, rt *RuntimeConf) error
GetNetworkCachedResult(net *NetworkConfig, rt *RuntimeConf) (types.Result, error)
GetNetworkCachedConfig(net *NetworkConfig, rt *RuntimeConf) ([]byte, *RuntimeConf, error)

ValidateNetworkList(ctx context.Context, net *NetworkConfigList) ([]string, error)
ValidateNetwork(ctx context.Context, net *NetworkConfig) ([]string, error)
Expand Down Expand Up @@ -175,6 +181,15 @@ func (c *CNIConfig) ensureExec() invoke.Exec {
return c.exec
}

type cachedInfo struct {
Kind string `json:"kind"`
Config []byte `json:"config"`
CniArgs [][2]string `json:"cniArgs,omitempty"`
CapabilityArgs map[string]interface{} `json:"capabilityArgs,omitempty"`
RawResult map[string]interface{} `json:"results,omitempty"`
Result types.Result `json:"-"`
}

// getCacheDir returns the cache directory in this order:
// 1) global cacheDir from CNIConfig object
// 2) deprecated cacheDir from RuntimeConf object
Expand All @@ -189,29 +204,79 @@ func (c *CNIConfig) getCacheDir(rt *RuntimeConf) string {
return CacheDir
}

func (c *CNIConfig) getResultCacheFilePath(netName string, rt *RuntimeConf) string {
func (c *CNIConfig) getCacheFilePath(netName string, rt *RuntimeConf) string {
return filepath.Join(c.getCacheDir(rt), "results", fmt.Sprintf("%s-%s-%s", netName, rt.ContainerID, rt.IfName))
}

func (c *CNIConfig) setCachedResult(result types.Result, netName string, rt *RuntimeConf) error {
func (c *CNIConfig) cacheAdd(result types.Result, config []byte, netName string, rt *RuntimeConf) error {

cached := cachedInfo{
Config: config,
Kind: CNICacheV1,
}
cached.CniArgs = rt.Args
cached.CapabilityArgs = rt.CapabilityArgs

// We need to get type.Result into cachedInfo as JSON map
// Marshal to []byte, then Unmarshal into cached.RawResult
data, err := json.Marshal(result)
if err != nil {
return err
}
fname := c.getResultCacheFilePath(netName, rt)

err = json.Unmarshal(data, &cached.RawResult)
if err != nil {
return err
}

newBytes, err := json.Marshal(&cached)
if err != nil {
return err
}

fname := c.getCacheFilePath(netName, rt)
if err := os.MkdirAll(filepath.Dir(fname), 0700); err != nil {
return err
}
return ioutil.WriteFile(fname, data, 0600)

return ioutil.WriteFile(fname, newBytes, 0600)
}

func (c *CNIConfig) delCachedResult(netName string, rt *RuntimeConf) error {
fname := c.getResultCacheFilePath(netName, rt)
func (c *CNIConfig) cacheDel(netName string, rt *RuntimeConf) error {
fname := c.getCacheFilePath(netName, rt)
return os.Remove(fname)
}

func (c *CNIConfig) getCachedResult(netName, cniVersion string, rt *RuntimeConf) (types.Result, error) {
fname := c.getResultCacheFilePath(netName, rt)
func (c *CNIConfig) getCachedConfig(netName string, rt *RuntimeConf) ([]byte, *RuntimeConf, error) {
var bytes []byte
var err error

fname := c.getCacheFilePath(netName, rt)
bytes, err = ioutil.ReadFile(fname)
if err != nil {
// Ignore read errors; the cached result may not exist on-disk
return nil, nil, nil
}

unmarshaled := cachedInfo{}
if err := json.Unmarshal(bytes, &unmarshaled); err != nil {
return nil, nil, fmt.Errorf("failed to unmarshal cached network %q config: %v", netName, err)
}
if unmarshaled.Kind != CNICacheV1 {
return nil, nil, fmt.Errorf("read cached network %q config has wrong kind: %v", netName, unmarshaled.Kind)
}

newRt := *rt
if unmarshaled.CniArgs != nil {
newRt.Args = unmarshaled.CniArgs
}
newRt.CapabilityArgs = unmarshaled.CapabilityArgs

return unmarshaled.Config, &newRt, nil
}

func (c *CNIConfig) getLegacyCachedResult(netName, cniVersion string, rt *RuntimeConf) (types.Result, error) {
fname := c.getCacheFilePath(netName, rt)
data, err := ioutil.ReadFile(fname)
if err != nil {
// Ignore read errors; the cached result may not exist on-disk
Expand Down Expand Up @@ -242,18 +307,72 @@ func (c *CNIConfig) getCachedResult(netName, cniVersion string, rt *RuntimeConf)
return result, err
}

func (c *CNIConfig) getCachedResult(netName, cniVersion string, rt *RuntimeConf) (types.Result, error) {
fname := c.getCacheFilePath(netName, rt)
fdata, err := ioutil.ReadFile(fname)
if err != nil {
// Ignore read errors; the cached result may not exist on-disk
return nil, nil
}

cachedInfo := cachedInfo{}
if err := json.Unmarshal(fdata, &cachedInfo); err != nil || cachedInfo.Kind != CNICacheV1 {
return c.getLegacyCachedResult(netName, cniVersion, rt)
}

newBytes, err := json.Marshal(&cachedInfo.RawResult)
if err != nil {
return nil, fmt.Errorf("failed to marshal cached network %q config: %v", netName, err)
}

// Read the version of the cached result
decoder := version.ConfigDecoder{}
resultCniVersion, err := decoder.Decode(newBytes)
if err != nil {
return nil, err
}

// Ensure we can understand the result
result, err := version.NewResult(resultCniVersion, newBytes)
if err != nil {
return nil, err
}

// Convert to the config version to ensure plugins get prevResult
// in the same version as the config. The cached result version
// should match the config version unless the config was changed
// while the container was running.
result, err = result.GetAsVersion(cniVersion)
if err != nil && resultCniVersion != cniVersion {
return nil, fmt.Errorf("failed to convert cached result version %q to config version %q: %v", resultCniVersion, cniVersion, err)
}
return result, err
}

// GetNetworkListCachedResult returns the cached Result of the previous
// previous AddNetworkList() operation for a network list, or an error.
// AddNetworkList() operation for a network list, or an error.
func (c *CNIConfig) GetNetworkListCachedResult(list *NetworkConfigList, rt *RuntimeConf) (types.Result, error) {
return c.getCachedResult(list.Name, list.CNIVersion, rt)
}

// GetNetworkCachedResult returns the cached Result of the previous
// previous AddNetwork() operation for a network, or an error.
// AddNetwork() operation for a network, or an error.
func (c *CNIConfig) GetNetworkCachedResult(net *NetworkConfig, rt *RuntimeConf) (types.Result, error) {
return c.getCachedResult(net.Network.Name, net.Network.CNIVersion, rt)
}

// GetNetworkListCachedConfig copies the input RuntimeConf to output
// RuntimeConf with fields updated with info from the cached Config.
func (c *CNIConfig) GetNetworkListCachedConfig(list *NetworkConfigList, rt *RuntimeConf) ([]byte, *RuntimeConf, error) {
return c.getCachedConfig(list.Name, rt)
}

// GetNetworkCachedConfig copies the input RuntimeConf to output
// RuntimeConf with fields updated with info from the cached Config.
func (c *CNIConfig) GetNetworkCachedConfig(net *NetworkConfig, rt *RuntimeConf) ([]byte, *RuntimeConf, error) {
return c.getCachedConfig(net.Network.Name, rt)
}

func (c *CNIConfig) addNetwork(ctx context.Context, name, cniVersion string, net *NetworkConfig, prevResult types.Result, rt *RuntimeConf) (types.Result, error) {
c.ensureExec()
pluginPath, err := c.exec.FindInPath(net.Network.Type, c.Path)
Expand All @@ -280,7 +399,7 @@ func (c *CNIConfig) AddNetworkList(ctx context.Context, list *NetworkConfigList,
}
}

if err = c.setCachedResult(result, list.Name, rt); err != nil {
if err = c.cacheAdd(result, list.Bytes, list.Name, rt); err != nil {
return nil, fmt.Errorf("failed to set network %q cached result: %v", list.Name, err)
}

Expand Down Expand Up @@ -364,7 +483,7 @@ func (c *CNIConfig) DelNetworkList(ctx context.Context, list *NetworkConfigList,
return err
}
}
_ = c.delCachedResult(list.Name, rt)
_ = c.cacheDel(list.Name, rt)

return nil
}
Expand All @@ -376,7 +495,7 @@ func (c *CNIConfig) AddNetwork(ctx context.Context, net *NetworkConfig, rt *Runt
return nil, err
}

if err = c.setCachedResult(result, net.Network.Name, rt); err != nil {
if err = c.cacheAdd(result, net.Bytes, net.Network.Name, rt); err != nil {
return nil, fmt.Errorf("failed to set network %q cached result: %v", net.Network.Name, err)
}

Expand Down Expand Up @@ -416,7 +535,7 @@ func (c *CNIConfig) DelNetwork(ctx context.Context, net *NetworkConfig, rt *Runt
if err := c.delNetwork(ctx, net.Network.Name, net.Network.CNIVersion, net, cachedResult, rt); err != nil {
return err
}
_ = c.delCachedResult(net.Network.Name, rt)
_ = c.cacheDel(net.Network.Name, rt)
return nil
}

Expand Down
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