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authorDaniel J Walsh <dwalsh@redhat.com>2018-03-29 11:01:47 -0400
committerAtomic Bot <atomic-devel@projectatomic.io>2018-04-05 14:13:49 +0000
commitfdcf633a33bbbfbc99268965ef5da03a4770619b (patch)
tree59be1ab815261e106220a4691766830b58657ac0 /pkg/hooks/hooks.go
parentca3b2414516c04125f986775c0cbce27f0f1e505 (diff)
downloadpodman-fdcf633a33bbbfbc99268965ef5da03a4770619b.tar.gz
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Add hooks support to podman
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com> Closes: #155 Approved by: mheon
Diffstat (limited to 'pkg/hooks/hooks.go')
-rw-r--r--pkg/hooks/hooks.go141
1 files changed, 141 insertions, 0 deletions
diff --git a/pkg/hooks/hooks.go b/pkg/hooks/hooks.go
new file mode 100644
index 000000000..dbcd7b773
--- /dev/null
+++ b/pkg/hooks/hooks.go
@@ -0,0 +1,141 @@
+package hooks
+
+import (
+ "encoding/json"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "regexp"
+ "strings"
+ "syscall"
+
+ spec "github.com/opencontainers/runtime-spec/specs-go"
+ "github.com/opencontainers/runtime-tools/generate"
+ "github.com/pkg/errors"
+ "github.com/sirupsen/logrus"
+)
+
+const (
+ // DefaultHooksDir Default directory containing hooks config files
+ DefaultHooksDir = "/usr/share/containers/oci/hooks.d"
+ // OverrideHooksDir Directory where admin can override the default configuration
+ OverrideHooksDir = "/etc/containers/oci/hooks.d"
+)
+
+// HookParams is the structure returned from read the hooks configuration
+type HookParams struct {
+ Hook string `json:"hook"`
+ Stage []string `json:"stage"`
+ Cmds []string `json:"cmd"`
+ Annotations []string `json:"annotation"`
+ HasBindMounts bool `json:"hasbindmounts"`
+ Arguments []string `json:"arguments"`
+}
+
+// readHook reads hooks json files, verifies it and returns the json config
+func readHook(hookPath string) (HookParams, error) {
+ var hook HookParams
+ raw, err := ioutil.ReadFile(hookPath)
+ if err != nil {
+ return hook, errors.Wrapf(err, "error Reading hook %q", hookPath)
+ }
+ if err := json.Unmarshal(raw, &hook); err != nil {
+ return hook, errors.Wrapf(err, "error Unmarshalling JSON for %q", hookPath)
+ }
+ if _, err := os.Stat(hook.Hook); err != nil {
+ return hook, errors.Wrapf(err, "unable to stat hook %q in hook config %q", hook.Hook, hookPath)
+ }
+ validStage := map[string]bool{"prestart": true, "poststart": true, "poststop": true}
+ for _, cmd := range hook.Cmds {
+ if _, err = regexp.Compile(cmd); err != nil {
+ return hook, errors.Wrapf(err, "invalid cmd regular expression %q defined in hook config %q", cmd, hookPath)
+ }
+ }
+ for _, cmd := range hook.Annotations {
+ if _, err = regexp.Compile(cmd); err != nil {
+ return hook, errors.Wrapf(err, "invalid cmd regular expression %q defined in hook config %q", cmd, hookPath)
+ }
+ }
+ for _, stage := range hook.Stage {
+ if !validStage[stage] {
+ return hook, errors.Wrapf(err, "unknown stage %q defined in hook config %q", stage, hookPath)
+ }
+ }
+ return hook, nil
+}
+
+// readHooks reads hooks json files in directory to setup OCI Hooks
+// adding hooks to the passedin hooks map.
+func readHooks(hooksPath string, hooks map[string]HookParams) error {
+ if _, err := os.Stat(hooksPath); err != nil {
+ if os.IsNotExist(err) {
+ logrus.Warnf("hooks path: %q does not exist", hooksPath)
+ return nil
+ }
+ return errors.Wrapf(err, "unable to stat hooks path %q", hooksPath)
+ }
+
+ files, err := ioutil.ReadDir(hooksPath)
+ if err != nil {
+ return err
+ }
+
+ for _, file := range files {
+ if !strings.HasSuffix(file.Name(), ".json") {
+ continue
+ }
+ hook, err := readHook(filepath.Join(hooksPath, file.Name()))
+ if err != nil {
+ return err
+ }
+ for key, h := range hooks {
+ // hook.Hook can only be defined in one hook file, unless it has the
+ // same name in the override path.
+ if hook.Hook == h.Hook && key != file.Name() {
+ return errors.Wrapf(syscall.EINVAL, "duplicate path, hook %q from %q already defined in %q", hook.Hook, hooksPath, key)
+ }
+ }
+ hooks[file.Name()] = hook
+ }
+ return nil
+}
+
+// SetupHooks takes a hookspath and reads all of the hooks in that directory.
+// returning a map of the configured hooks
+func SetupHooks(hooksPath string) (map[string]HookParams, error) {
+ hooksMap := make(map[string]HookParams)
+ if err := readHooks(hooksPath, hooksMap); err != nil {
+ return nil, err
+ }
+ if hooksPath == DefaultHooksDir {
+ if err := readHooks(OverrideHooksDir, hooksMap); err != nil {
+ return nil, err
+ }
+ }
+
+ return hooksMap, nil
+}
+
+// AddOCIHook generates OCI specification using the included hook
+func AddOCIHook(g *generate.Generator, hook HookParams) error {
+ for _, stage := range hook.Stage {
+ h := spec.Hook{
+ Path: hook.Hook,
+ Args: append([]string{hook.Hook}, hook.Arguments...),
+ Env: []string{fmt.Sprintf("stage=%s", stage)},
+ }
+ logrus.Debugf("AddOCIHook", h)
+ switch stage {
+ case "prestart":
+ g.AddPreStartHook(h)
+
+ case "poststart":
+ g.AddPostStartHook(h)
+
+ case "poststop":
+ g.AddPostStopHook(h)
+ }
+ }
+ return nil
+}