feat: add the check_output_matches plugin #5
3 changed files with 412 additions and 0 deletions
95
cmd/matches/cmdline.go
Normal file
95
cmd/matches/cmdline.go
Normal file
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@ -0,0 +1,95 @@
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package matches // import nocternity.net/gomonop/cmd/matches
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import (
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"context"
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"regexp"
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"strings"
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"time"
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"github.com/karrick/golf"
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"nocternity.net/gomonop/pkg/perfdata"
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)
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// pluginFlags represent command line flags that have been parsed.
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type pluginFlags struct {
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isFile bool // Are we reading from a file?
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dataSource string // The file or command to read from
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timeout time.Duration // A timeout for the command, or 0 to disable
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matches []matchConfig // Configuration for the matches to check
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strict bool // Reject lines that don't match anything
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}
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// matchConfig is the configuration for a single match to check.
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type matchConfig struct {
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isRegexp bool // Are we checking against a regular expression?
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matchString string // The string or regexp to match
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compiledRe *regexp.Regexp // The compiled regexp
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warn *perfdata.Range // Warning range
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crit *perfdata.Range // Critical range
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}
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// parseArguments parses command line arguments for the plugin.
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func (p *pluginFlags) parseArguments() {
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golf.BoolVarP(&p.isFile, 'f', "is-file", false, "Are we reading from a file?")
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golf.StringVarP(&p.dataSource, 's', "source", "", "The file or command to read from")
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golf.DurationVarP(&p.timeout, 'T', "timeout", 0, "A timeout for the command, or 0 to disable")
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golf.BoolVarP(&p.strict, 'S', "strict", false, "Reject lines that do not match anything")
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isRegexp := golf.BoolP('R', "no-regexp", true, "Following match argument will be a basic string")
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golf.BoolVarP(isRegexp, 'r', "regexp", false, "Following match argument will be a regexp")
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var wRange *perfdata.Range
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golf.StringFuncP('w', "warn", "", "Warning range, in Nagios-compatible format", func(s string) error {
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locRange, err := perfdata.ParseRange(s)
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if err == nil {
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wRange = locRange
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}
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return err
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})
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golf.BoolFuncP('W', "no-warn", false, "Clear warning range", func(bool) error {
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wRange = nil
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return nil
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})
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var cRange *perfdata.Range
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golf.StringFuncP('c', "critical", "", "Critical range, in Nagios-compatible format", func(s string) error {
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locRange, err := perfdata.ParseRange(s)
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if err == nil {
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cRange = locRange
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}
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return err
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})
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golf.BoolFuncP('C', "no-critical", false, "Clear warning range", func(bool) error {
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cRange = nil
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return nil
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})
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golf.StringFuncP('m', "match", "", "Match string", func(s string) error {
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p.matches = append(p.matches, matchConfig{
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isRegexp: *isRegexp,
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matchString: s,
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warn: wRange,
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crit: cRange,
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})
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return nil
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})
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golf.Parse()
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}
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// makeContext generates a context based on the timeout, if one is set.
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func (p *pluginFlags) makeContext() (context.Context, context.CancelFunc) {
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if p.timeout == 0 {
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return context.Background(), func() {}
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}
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return context.WithTimeout(context.Background(), p.timeout)
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}
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// matches check if the specified string matches a configuration.
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func (p *matchConfig) matches(s string) bool {
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if p.isRegexp {
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return p.compiledRe.MatchString(s)
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}
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return strings.Contains(s, p.matchString)
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}
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315
cmd/matches/plugin.go
Normal file
315
cmd/matches/plugin.go
Normal file
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@ -0,0 +1,315 @@
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// The matches package contains the implementation of the `check_output_matches`
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// plugin, which can be used to run an arbitrary command and check its output
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// against various patterns. It can also be configured to do the same on an
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// arbitrary file.
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package matches // import nocternity.net/gomonop/cmd/matches
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import (
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"bufio"
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"context"
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"fmt"
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"io"
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"os"
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"os/exec"
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"regexp"
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"strconv"
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"strings"
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"nocternity.net/gomonop/pkg/perfdata"
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"nocternity.net/gomonop/pkg/plugin"
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"nocternity.net/gomonop/pkg/results"
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"nocternity.net/gomonop/pkg/status"
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)
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// Program data for the string matches plugin.
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type matchesPlugin struct {
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pluginFlags // Flags from the command line
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results *results.Results // Plugin output state
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counters []int // Counters for each match
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unmatchedLines int // Number of lines that didn't match anything
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}
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// Initialise the plugin.
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func NewPlugin() plugin.Plugin {
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pluginInst := &matchesPlugin{
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results: results.New("String matches counter"),
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}
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pluginInst.parseArguments()
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return pluginInst
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}
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// Return the program's output value.
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func (pluginInst *matchesPlugin) Results() *results.Results {
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return pluginInst.results
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}
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// Check the values that were specified from the command line. Returns true
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// if the arguments made sense.
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func (pluginInst *matchesPlugin) CheckArguments() bool {
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if pluginInst.dataSource == "" {
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pluginInst.results.SetState(status.StatusUnknown, "no data source specified")
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return false
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}
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if !pluginInst.strict && len(pluginInst.matches) == 0 {
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pluginInst.results.SetState(status.StatusUnknown, "would match anything")
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return false
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}
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for index := range pluginInst.matches {
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if pluginInst.matches[index].matchString == "" {
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pluginInst.results.SetState(status.StatusUnknown, "empty match string")
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pluginInst.results.AddLinef("(At match %d)", index+1)
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return false
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}
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if pluginInst.matches[index].isRegexp {
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rexp, err := regexp.Compile(pluginInst.matches[index].matchString)
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if err != nil {
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pluginInst.results.SetState(status.StatusUnknown, "Invalid regular expression")
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pluginInst.results.AddLine(err.Error())
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pluginInst.results.AddLinef("(At match %d)", index+1)
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return false
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}
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pluginInst.matches[index].compiledRe = rexp
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}
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}
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return true
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}
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// readFromFile starts a goroutine that reads from the file and sends each line
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// to the dataPipe.
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func (pluginInst *matchesPlugin) readFromFile(ctx context.Context, donePipe chan error, dataPipe chan string) {
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go func() {
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file, err := os.Open(pluginInst.dataSource)
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if err != nil {
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donePipe <- err
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return
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}
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defer file.Close()
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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select {
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case <-ctx.Done():
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donePipe <- ctx.Err()
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return
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case dataPipe <- scanner.Text():
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}
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}
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donePipe <- scanner.Err()
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}()
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}
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// startPipeCopy starts a goroutine that copies data from the reader to the
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// dataPipe.
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func startPipeCopy(reader io.Reader, dataPipe chan string) (aborter chan struct{}, readError chan error) {
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aborter = make(chan struct{})
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readError = make(chan error)
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go func() {
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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select {
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case <-aborter:
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return
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case dataPipe <- scanner.Text():
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}
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}
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readError <- scanner.Err()
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}()
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return
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}
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// readFromProgram starts a goroutine that controls the program, sending lines
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// from both stderr and stdout to the dataPipe.
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func (pluginInst *matchesPlugin) readFromProgram(ctx context.Context, donePipe chan error, dataPipe chan string) {
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go func() {
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cmd := exec.Command(pluginInst.dataSource) //nolint:gosec // Command is in fact user-provided
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stdout, err := cmd.StdoutPipe()
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if err != nil {
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donePipe <- err
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return
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}
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stderr, err := cmd.StderrPipe()
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if err != nil {
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donePipe <- err
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return
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}
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if err := cmd.Start(); err != nil {
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donePipe <- err
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return
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}
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outAborter, outReadError := startPipeCopy(stdout, dataPipe)
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errAborter, errReadError := startPipeCopy(stderr, dataPipe)
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defer func() {
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_ = stdout.Close()
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_ = stderr.Close()
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close(outAborter)
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close(errAborter)
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close(outReadError)
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close(errReadError)
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}()
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abort := func(err error) {
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outAborter <- struct{}{}
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errAborter <- struct{}{}
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_ = cmd.Process.Kill()
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donePipe <- err
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}
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errComplete := false
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outComplete := false
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for !(errComplete && outComplete) {
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select {
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case <-ctx.Done():
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abort(ctx.Err())
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return
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case err := <-outReadError:
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if err != nil {
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abort(err)
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return
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}
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outComplete = true
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case err := <-errReadError:
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if err != nil {
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abort(err)
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return
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}
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errComplete = true
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}
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}
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donePipe <- cmd.Wait()
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}()
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}
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// startReading starts reading data from either a file or a program.
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func (pluginInst *matchesPlugin) startReading(ctx context.Context, donePipe chan error, dataPipe chan string) {
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if pluginInst.isFile {
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pluginInst.readFromFile(ctx, donePipe, dataPipe)
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} else {
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pluginInst.readFromProgram(ctx, donePipe, dataPipe)
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}
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}
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// processLine processes a single line obtained from the program or file.
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func (pluginInst *matchesPlugin) processLine(line string) {
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hadMatch := false
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for index := range pluginInst.matches {
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if pluginInst.matches[index].matches(line) {
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pluginInst.counters[index]++
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hadMatch = true
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}
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}
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if !hadMatch {
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pluginInst.unmatchedLines++
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}
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}
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// processData processes data from either the program or the file.
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func (pluginInst *matchesPlugin) processData() error {
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ctx, cancel := pluginInst.makeContext()
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defer cancel()
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donePipe := make(chan error)
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dataPipe := make(chan string)
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pluginInst.startReading(ctx, donePipe, dataPipe)
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defer func() {
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close(donePipe)
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close(dataPipe)
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}()
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for {
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select {
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case line := <-dataPipe:
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pluginInst.processLine(line)
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case err := <-donePipe:
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return err
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}
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}
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}
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// checkResults checks the various counters against their configured thresholds,
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// and the strict mode failure count.
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func (pluginInst *matchesPlugin) checkResults(readError error) {
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nWarns, nCrits, nUnknowns := 0, 0, 0
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for index := range pluginInst.counters {
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config := &pluginInst.matches[index]
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var nature string
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if config.isRegexp {
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nature = "regexp"
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} else {
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nature = "substring"
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}
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label := fmt.Sprintf("#%2d : %s %s", index+1, nature, config.matchString)
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value := strconv.Itoa(pluginInst.counters[index])
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pdat := perfdata.New(label, perfdata.UomNone, value)
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pdat.SetWarn(config.warn)
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pdat.SetCrit(config.crit)
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pluginInst.results.AddPerfData(pdat)
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switch pdat.GetStatus() {
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case status.StatusCritical:
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nCrits++
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case status.StatusWarning:
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nWarns++
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case status.StatusUnknown:
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nUnknowns++
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}
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}
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umlPdat := perfdata.New("unmatched", perfdata.UomNone, strconv.Itoa(pluginInst.unmatchedLines))
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if pluginInst.strict {
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umlPdat.SetCrit(perfdata.RangeMinMax("~", "0"))
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}
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switch umlPdat.GetStatus() {
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case status.StatusCritical:
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nCrits++
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}
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pluginInst.results.AddPerfData(umlPdat)
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problems := []string{}
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if nCrits > 0 {
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problems = append(problems, fmt.Sprintf("%d value(s) critical", nCrits))
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}
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if nWarns > 0 {
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problems = append(problems, fmt.Sprintf("%d value(s) warning", nWarns))
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}
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if nUnknowns > 0 {
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problems = append(problems, fmt.Sprintf("%d value(s) unknown", nUnknowns))
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}
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if len(problems) == 0 {
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problems = append(problems, "No match errors")
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}
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if readError != nil {
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pluginInst.results.AddLinef("Error while reading data: %s", readError.Error())
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nUnknowns++
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}
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var finalStatus status.Status
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switch {
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case nCrits > 0:
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finalStatus = status.StatusCritical
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case nWarns > 0:
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finalStatus = status.StatusWarning
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case nUnknowns > 0:
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finalStatus = status.StatusUnknown
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default:
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finalStatus = status.StatusOK
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}
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pluginInst.results.SetState(finalStatus, strings.Join(problems, ", "))
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}
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// Run the check.
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func (pluginInst *matchesPlugin) RunCheck() {
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pluginInst.counters = make([]int, len(pluginInst.matches))
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err := pluginInst.processData()
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pluginInst.checkResults(err)
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}
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2
main.go
2
main.go
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@ -5,6 +5,7 @@ import (
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"os"
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"path/filepath"
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"nocternity.net/gomonop/cmd/matches"
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"nocternity.net/gomonop/cmd/sslcert"
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"nocternity.net/gomonop/cmd/zoneserial"
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"nocternity.net/gomonop/pkg/plugin"
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@ -14,6 +15,7 @@ import (
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var (
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plugins map[string]plugin.Builder = map[string]plugin.Builder{
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"check_output_matches": matches.NewPlugin,
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"check_ssl_certificate": sslcert.NewProgram,
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"check_zone_serial": zoneserial.NewProgram,
|
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}
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|
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Reference in a new issue