refactor(matches): split the external program handling code into more functions
This commit is contained in:
parent
09df5aa44e
commit
2b58a27cc0
4 changed files with 336 additions and 239 deletions
116
cmd/matches/extprogram.go
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116
cmd/matches/extprogram.go
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@ -0,0 +1,116 @@
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package matches // import nocternity.net/gomonop/pkg/matches
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import (
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"bufio"
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"context"
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"io"
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"os/exec"
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)
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// streamObtainer refers to functions that may return either an input stream or
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// an error.
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type streamObtainer func() (io.ReadCloser, error)
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// pipeCopy encapsulates the structures that are used to transfer data from a
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// single stream to the reader.
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type pipeCopy struct {
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reader io.ReadCloser // The input stream being read from
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dataPipe chan string // Channel that receives the data we read
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aborter chan struct{} // Channel that causes the copy to abort
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readResult chan error // Channel that returns results from reading
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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(obtainer streamObtainer, pipes *readerPipes) *pipeCopy {
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stream, err := obtainer()
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if err != nil {
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pipes.done <- err
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return nil
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}
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pipeCopyData := &pipeCopy{
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reader: stream,
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dataPipe: pipes.data,
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aborter: make(chan struct{}),
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readResult: make(chan error),
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}
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go pipeCopyData.run()
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return pipeCopyData
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}
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// run runs the copy operation from the input stream to the data pipe. It is
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// meant to be executed as a goroutine.
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func (pc *pipeCopy) run() {
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scanner := bufio.NewScanner(pc.reader)
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for scanner.Scan() {
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select {
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case <-pc.aborter:
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return
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case pc.dataPipe <- scanner.Text():
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}
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}
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pc.readResult <- scanner.Err()
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}
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// close closes the stream and channels used by a copy pipe.
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func (pc *pipeCopy) close() {
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pc.abort()
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_ = pc.reader.Close()
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close(pc.aborter)
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close(pc.readResult)
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}
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// abort causes the pipe copy to be aborted.
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func (pc *pipeCopy) abort() {
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pc.aborter <- struct{}{}
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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, pipes *readerPipes) {
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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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outs := startPipeCopy(func() (io.ReadCloser, error) { return cmd.StdoutPipe() }, pipes)
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defer outs.close()
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errs := startPipeCopy(func() (io.ReadCloser, error) { return cmd.StderrPipe() }, pipes)
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defer errs.close()
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if err := cmd.Start(); err != nil {
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pipes.done <- err
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return
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}
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abort := func(err error) {
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_ = cmd.Process.Kill()
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pipes.done <- 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 := <-outs.readResult:
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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 := <-errs.readResult:
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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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pipes.done <- cmd.Wait()
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}()
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}
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@ -5,17 +5,8 @@
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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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@ -77,236 +68,6 @@ func (pluginInst *matchesPlugin) CheckArguments() bool {
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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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95
cmd/matches/reader.go
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95
cmd/matches/reader.go
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@ -0,0 +1,95 @@
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package matches // import nocternity.net/gomonop/pkg/matches
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import (
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"bufio"
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"context"
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"os"
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)
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// readerPipes encapsulates the two channels used to communicate data and state
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// from the functions that acquire the data.
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type readerPipes struct {
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done chan error
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data chan string
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}
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// makeReaderPipes initializes the channels.
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func makeReaderPipes() *readerPipes {
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return &readerPipes{
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done: make(chan error),
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data: make(chan string),
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}
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}
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// close closes the channels.
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func (rdp *readerPipes) close() {
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close(rdp.done)
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close(rdp.data)
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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, pipes *readerPipes) {
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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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pipes.done <- 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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pipes.done <- ctx.Err()
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return
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case pipes.data <- scanner.Text():
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}
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}
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pipes.done <- scanner.Err()
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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, pipes *readerPipes) {
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if pluginInst.isFile {
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pluginInst.readFromFile(ctx, pipes)
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} else {
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pluginInst.readFromProgram(ctx, pipes)
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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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pipes := makeReaderPipes()
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defer pipes.close()
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pluginInst.startReading(ctx, pipes)
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for {
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select {
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case line := <-pipes.data:
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pluginInst.processLine(line)
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case err := <-pipes.done:
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return err
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}
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}
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}
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125
cmd/matches/results.go
Normal file
125
cmd/matches/results.go
Normal file
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@ -0,0 +1,125 @@
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package matches // import nocternity.net/gomonop/cmd/matches
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import (
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"fmt"
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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/status"
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)
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// resultsInfo contains information about results being processed.
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type resultsInfo struct {
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nWarns, nCrits, nUnknowns uint
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}
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// updateResults updates the result counters based on the specified status.
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func (info *resultsInfo) updateFrom(itemStatus status.Status) {
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switch itemStatus {
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case status.StatusCritical:
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info.nCrits++
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case status.StatusWarning:
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info.nWarns++
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case status.StatusUnknown:
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info.nUnknowns++
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case status.StatusOK:
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// do nothing
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}
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}
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// toProblems generate the list of problems found while running the plugin,
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// as a string which can be returned to the monitoring server.
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func (info *resultsInfo) toProblems() string {
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problems := []string{}
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if info.nCrits > 0 {
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problems = append(problems,
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fmt.Sprintf("%d value(s) critical", info.nCrits),
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)
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}
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if info.nWarns > 0 {
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problems = append(problems,
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fmt.Sprintf("%d value(s) warning", info.nWarns),
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)
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}
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if info.nUnknowns > 0 {
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problems = append(problems,
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fmt.Sprintf("%d value(s) unknown", info.nUnknowns),
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)
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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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return strings.Join(problems, ", ")
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}
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// toStatus computes the final status of the plugin based on the status
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// counters.
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func (info *resultsInfo) toStatus() status.Status {
|
||||
switch {
|
||||
case info.nCrits > 0:
|
||||
return status.StatusCritical
|
||||
case info.nWarns > 0:
|
||||
return status.StatusWarning
|
||||
case info.nUnknowns > 0:
|
||||
return status.StatusUnknown
|
||||
default:
|
||||
return status.StatusOK
|
||||
}
|
||||
}
|
||||
|
||||
// checkCounters checks the match counters against their configured thresholds,
|
||||
// if any, and adds the corresponding perf data to the result. It initializes a
|
||||
// resultsInfo structure containing the counts of critical, warning and unknown
|
||||
// statuses gathered so far.
|
||||
func (pluginInst *matchesPlugin) checkCounters() resultsInfo {
|
||||
info := resultsInfo{}
|
||||
|
||||
for index := range pluginInst.counters {
|
||||
config := &pluginInst.matches[index]
|
||||
|
||||
var nature string
|
||||
if config.isRegexp {
|
||||
nature = "regexp"
|
||||
} else {
|
||||
nature = "substring"
|
||||
}
|
||||
label := fmt.Sprintf("#%2d : %s %s", index+1, nature, config.matchString)
|
||||
value := strconv.Itoa(pluginInst.counters[index])
|
||||
|
||||
pdat := perfdata.New(label, perfdata.UomNone, value)
|
||||
pdat.SetWarn(config.warn)
|
||||
pdat.SetCrit(config.crit)
|
||||
pluginInst.results.AddPerfData(pdat)
|
||||
|
||||
info.updateFrom(pdat.GetStatus())
|
||||
}
|
||||
|
||||
return info
|
||||
}
|
||||
|
||||
// checkUnmatched checks the unmatched lines counters, applying a limit if
|
||||
// strict mode is enabled. The corresponding performance data is added to the
|
||||
// result.
|
||||
func (pluginInst *matchesPlugin) checkUnmatched(info *resultsInfo) {
|
||||
umlPdat := perfdata.New("unmatched", perfdata.UomNone, strconv.Itoa(pluginInst.unmatchedLines))
|
||||
if pluginInst.strict {
|
||||
umlPdat.SetCrit(perfdata.RangeMinMax("~", "0"))
|
||||
}
|
||||
info.updateFrom(umlPdat.GetStatus())
|
||||
pluginInst.results.AddPerfData(umlPdat)
|
||||
}
|
||||
|
||||
// checkResults checks the various counters against their configured thresholds,
|
||||
// and the strict mode failure count.
|
||||
func (pluginInst *matchesPlugin) checkResults(readError error) {
|
||||
info := pluginInst.checkCounters()
|
||||
pluginInst.checkUnmatched(&info)
|
||||
|
||||
if readError != nil {
|
||||
pluginInst.results.AddLinef("Error while reading data: %s", readError.Error())
|
||||
info.nUnknowns++
|
||||
}
|
||||
|
||||
pluginInst.results.SetState(info.toStatus(), info.toProblems())
|
||||
}
|
Loading…
Reference in a new issue