Big rafactoring : code split in several modules and some other best practices

state/header.go

@@ -0,0 +1,57 @@
+package state
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"log"
+	"os"
+)
+
+// c.StateFile()HeaderLength : the length of the state file header struct
+const headerLength = 14 + 2 + 4 + 4 + 8 + 8 + 19*8
+
+// header : A structure to hold the header of the state file. It is statically aligned for amd64 architecture
+// This comes from bareos repository file core/src/lib/bsys.cc:525 and core/src/lib/bsys.cc:652
+type header struct {
+	ID                        [14]byte
+	_                         int16
+	Version                   int32
+	_                         int32
+	LastJobsAddr              uint64
+	EndOfRecentJobResultsList uint64
+	Reserved                  [19]uint64
+}
+
+func (sfh header) String() string {
+	return fmt.Sprintf("ID: \"%s\", Version: %d, LastJobsAddr: %d, EndOfRecentJobResultsList: %d", sfh.ID[:len(sfh.ID)-2], sfh.Version, sfh.EndOfRecentJobResultsList, sfh.Reserved)
+}
+
+func (s *State) parseHeader(file *os.File) (err error) {
+	// Parsing the state file header
+	n, data, err := s.readNextBytes(file, headerLength)
+	if err != nil {
+		return fmt.Errorf("INFO Corrupted state file : %s", err)
+	}
+	if n != headerLength {
+		return fmt.Errorf("INFO Corrupted state file : invalid header length in %s", s.config.StateFile())
+	}
+	buffer := bytes.NewBuffer(data)
+	err = binary.Read(buffer, binary.LittleEndian, &s.header)
+	if err != nil {
+		return fmt.Errorf("INFO Corrupted state file : binary.Read failed on header in %s : %s", s.config.StateFile(), err)
+	}
+	if s.config.Verbose() {
+		log.Printf("Parsed header: %+s\n", s.header)
+	}
+	if id := string(s.header.ID[:len(s.header.ID)-1]); id != "Bareos State\n" && id != "Bacula State\n" {
+		return fmt.Errorf("INFO Corrupted state file : Not a bareos or bacula state file %s", s.config.StateFile())
+	}
+	if s.header.Version != 4 {
+		return fmt.Errorf("INFO Invalid state file : This script only supports bareos state file version 4, got %d", s.header.Version)
+	}
+	if s.header.LastJobsAddr == 0 {
+		return fmt.Errorf("INFO No jobs exist in the state file")
+	}
+	return
+}

state/job.go

@@ -0,0 +1,103 @@
+package state
+
+import (
+	"bareos-zabbix-check/job"
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"log"
+	"os"
+	"regexp"
+	"time"
+)
+
+// jobLength : the length of the job result struct
+const jobLength = 16 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 8 + 8 + 8 + maxNameLength
+
+var jobNameRegex = regexp.MustCompilePOSIX(`^([-A-Za-z0-9_]+)\.[0-9]{4}-[0-9]{2}-[0-9]{2}.*`)
+
+// jobEntry : A structure to hold a job result from the state file
+// This comes from bareos repository file core/src/lib/recent_job_results_list.h:29 and file core/src/lib/recent_job_results_list.cc:44
+type jobEntry struct {
+	Pad            [16]byte
+	Errors         int32
+	JobType        int32
+	JobStatus      int32
+	JobLevel       int32
+	JobID          uint32
+	VolSessionID   uint32
+	VolSessionTime uint32
+	JobFiles       uint32
+	JobBytes       uint64
+	StartTime      uint64
+	EndTime        uint64
+	Job            [maxNameLength]byte
+}
+
+func (je jobEntry) String() string {
+	var matches = jobNameRegex.FindSubmatchIndex(je.Job[:])
+	var jobNameLen int
+	if len(matches) >= 4 {
+		jobNameLen = matches[3]
+	}
+	return fmt.Sprintf("Errors: %d, JobType: %c, JobStatus: %c, JobLevel: %c, JobID: %d, VolSessionID: %d, VolSessionTime: %d, JobFiles: %d, JobBytes: %d, StartTime: %s, EndTime: %s, Job: %s",
+		je.Errors, je.JobType, je.JobStatus, je.JobLevel, je.JobID, je.VolSessionID, je.VolSessionTime, je.JobFiles, je.JobBytes, time.Unix(int64(je.StartTime), 0), time.Unix(int64(je.EndTime), 0), je.Job[:jobNameLen])
+}
+
+func (s *State) parseJobs(file *os.File) (err error) {
+	// We seek to the jobs position in the state file
+	file.Seek(int64(s.header.LastJobsAddr), 0)
+
+	// We read how many jobs there are in the state file
+	n, data, err := s.readNextBytes(file, 4)
+	if err != nil {
+		return fmt.Errorf("INFO Corrupted state file : %s", err)
+	}
+	if n != 4 {
+		return fmt.Errorf("INFO Corrupted state file : invalid numberOfJobs read length in %s", s.config.StateFile())
+	}
+	buffer := bytes.NewBuffer(data)
+	var numberOfJobs uint32
+	err = binary.Read(buffer, binary.LittleEndian, &numberOfJobs)
+	if err != nil {
+		return fmt.Errorf("INFO Corrupted state file : binary.Read failed on numberOfJobs in %s : %s", s.config.StateFile(), err)
+	}
+	if s.config.Verbose() {
+		log.Printf("%d jobs found in state file\n", numberOfJobs)
+	}
+
+	// We parse the job entries
+	for ; numberOfJobs > 0; numberOfJobs-- {
+		var (
+			jobResult jobEntry
+			jobName   string
+		)
+		n, data, err = s.readNextBytes(file, jobLength)
+		if err != nil {
+			return fmt.Errorf("INFO Corrupted state file : %s", err)
+		}
+		if n != jobLength {
+			return fmt.Errorf("INFO Corrupted state file : invalid job entry in %s", s.config.StateFile())
+		}
+		buffer = bytes.NewBuffer(data)
+		err = binary.Read(buffer, binary.LittleEndian, &jobResult)
+		if err != nil {
+			return fmt.Errorf("INFO Corrupted state file : binary.Read failed on job entry in %s : %s", s.config.StateFile(), err)
+		}
+		matches := jobNameRegex.FindSubmatchIndex(jobResult.Job[:])
+		if len(matches) >= 4 {
+			jobName = string(jobResult.Job[:matches[3]])
+		} else {
+			return fmt.Errorf("INFO Couldn't parse job name, this shouldn't happen : %s", jobResult.Job[:])
+		}
+		if s.config.Verbose() {
+			log.Printf("Parsed job entry: %s\n", jobResult)
+		}
+		// If the job is of type backup (B == ascii 66)
+		if jobResult.JobType == 66 {
+			// If the job is of status success JobStatus is equals to 84 (T == ascii 84)
+			s.jobs = append(s.jobs, job.Job{Name: jobName, Timestamp: jobResult.StartTime, Success: jobResult.JobStatus == 84})
+		}
+	}
+	return
+}

state/parser.go

@@ -0,0 +1,40 @@
+package state
+
+import (
+	"bareos-zabbix-check/config"
+	"fmt"
+	"os"
+)
+
+// Parse parses a bareos state file
+func (s *State) Parse(c *config.Config) (err error) {
+	s.config = c
+	// Open the state file
+	file, err := os.Open(c.StateFile())
+	if err != nil {
+		return fmt.Errorf("INFO Couldn't open state file : %s", err)
+	}
+	defer file.Close()
+
+	err = s.parseHeader(file)
+	if err != nil {
+		return err
+	}
+	err = s.parseJobs(file)
+	if err != nil {
+		return err
+	}
+
+	return
+}
+
+// readNextBytes : Reads the next "number" bytes from a "file", returns the number of bytes actually read as well as the bytes read
+func (s *State) readNextBytes(file *os.File, number int) (n int, bytes []byte, err error) {
+	bytes = make([]byte, number)
+	n, err = file.Read(bytes)
+	if err != nil {
+		return 0, nil, fmt.Errorf("file.Read failed in %s : %s", s.config.StateFile(), err)
+	}
+
+	return
+}

state/state.go

@@ -0,0 +1,21 @@
+package state
+
+import (
+	"bareos-zabbix-check/config"
+	"bareos-zabbix-check/job"
+)
+
+// maxNameLength : the maximum length of a string, hard coded in bareos
+const maxNameLength = 128
+
+// State is an object for manipulating a bareos state file
+type State struct {
+	config *config.Config
+	header header
+	jobs   []job.Job
+}
+
+// Jobs returns the jobs from the state file
+func (s *State) Jobs() []job.Job {
+	return s.jobs
+}