120 lines
3.6 KiB
Go
120 lines
3.6 KiB
Go
package util
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import (
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"encoding/json"
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"errors"
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"log"
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"os"
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"path"
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"git.hamburg.ccc.de/ccchh/spaceapid/types"
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)
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const (
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savedStateJSONPath = "/var/lib/spaceapid/spaceapid-state.json"
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)
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// MergeOldState merges a given SpaceAPIResponse with the state saved at the time of last program exit and then deletes
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// the file containing the old state.
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func MergeOldState(response *types.SpaceAPIResponseV14) {
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var (
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err error
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oldState []byte
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persistedState types.PersistentStateV14
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)
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log.Println("Merging old state from", savedStateJSONPath, "...")
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// Check if state.json is present
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_, err = os.Stat(savedStateJSONPath)
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if err != nil {
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log.Println("Old state json not accessible at", savedStateJSONPath, ", skipping merge... error:", err)
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if errors.Is(err, os.ErrNotExist) {
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return
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}
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goto removeOld
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}
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// Read file and load persisted state
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oldState, err = os.ReadFile(savedStateJSONPath)
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if err != nil {
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log.Println("Error reading old state from", savedStateJSONPath, ", skipping merge... error:", err)
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goto removeOld
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}
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err = json.Unmarshal(oldState, &persistedState)
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if err != nil {
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log.Println(savedStateJSONPath, "doesn't seem to contain valid data... error:", err)
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goto removeOld
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}
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// Merge state
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response.State = persistedState.State
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// Merge sensors
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for key, environmentSensors := range persistedState.Sensors {
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for _, sensor := range environmentSensors {
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// Order or amount of sensors might have changed, so check sensors already present in response
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// and then look for matching values in persisted state
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for i := range response.Sensors[key] {
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if rs := &response.Sensors[key][i]; rs.Location == sensor.Location && rs.Name == sensor.Name {
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rs.Value = sensor.Value
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rs.LastChange = sensor.LastChange
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}
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}
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}
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}
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// Delete old state json
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removeOld:
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err = os.RemoveAll(savedStateJSONPath)
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if err != nil {
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log.Println("Failed to remove", savedStateJSONPath, ", continuing... error:", err)
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}
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}
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func SaveCurrentState(response types.SpaceAPIResponseV14) {
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// Create state directory if not present
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err := os.MkdirAll(path.Dir(savedStateJSONPath), 0750)
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if err != nil {
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log.Fatalln("Failed creating", savedStateJSONPath, ", aborting... error:", err)
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}
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// Open persistent state file
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file, err := os.OpenFile(savedStateJSONPath, os.O_WRONLY|os.O_CREATE, 0644)
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if err != nil {
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log.Fatalln("Failed opening", savedStateJSONPath, "while trying to save current state... error:", err)
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}
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defer file.Close()
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// Create persistent state
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persistentStateV14 := types.PersistentStateV14{
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State: struct {
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Open bool `json:"open"`
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LastChange int64 `json:"lastchange"`
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}{Open: response.State.Open, LastChange: response.State.LastChange},
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}
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// Save sensor state
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persistentStateV14.Sensors = make(map[string][]types.PersistentEnvironmentSensor)
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for key, environmentSensors := range response.Sensors {
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persistentStateV14.Sensors[key] = make([]types.PersistentEnvironmentSensor, len(environmentSensors))
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for i, sensor := range environmentSensors {
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persistentStateV14.Sensors[key][i].Value = sensor.Value
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persistentStateV14.Sensors[key][i].Location = sensor.Location
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persistentStateV14.Sensors[key][i].Name = sensor.Name
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persistentStateV14.Sensors[key][i].LastChange = sensor.LastChange
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}
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}
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// Serialize persistent state
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marshal, err := json.MarshalIndent(persistentStateV14, "", "\t")
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if err != nil {
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log.Fatalln("Failed serializing persistent state... error:", err)
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}
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// Write to file
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_, err = file.Write(marshal)
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if err != nil {
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log.Fatalln("Failed writing persistent state to file", file.Name(), "... error:", err)
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}
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}
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