Matt Holloway
74 lines
2.0 KiB
Go
74 lines
2.0 KiB
Go
package buffer
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import (
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"bufio"
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"fmt"
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"net/http"
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"strings"
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)
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// ProcessResponseAsRingBufferToEnd reads the body of an HTTP response line by line,
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// storing only the last maxJobLogLines lines using a ring buffer (sliding window).
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// This efficiently retains the most recent lines, overwriting older ones as needed.
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//
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// Parameters:
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//
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// httpResp: The HTTP response whose body will be read.
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// maxJobLogLines: The maximum number of log lines to retain.
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//
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// Returns:
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//
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// string: The concatenated log lines (up to maxJobLogLines), separated by newlines.
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// int: The total number of lines read from the response.
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// *http.Response: The original HTTP response.
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// error: Any error encountered during reading.
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//
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// The function uses a ring buffer to efficiently store only the last maxJobLogLines lines.
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// If the response contains more lines than maxJobLogLines, only the most recent lines are kept.
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func ProcessResponseAsRingBufferToEnd(httpResp *http.Response, maxJobLogLines int) (string, int, *http.Response, error) {
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if maxJobLogLines > 100000 {
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maxJobLogLines = 100000
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}
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lines := make([]string, maxJobLogLines)
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validLines := make([]bool, maxJobLogLines)
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totalLines := 0
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writeIndex := 0
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scanner := bufio.NewScanner(httpResp.Body)
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scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
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for scanner.Scan() {
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line := scanner.Text()
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totalLines++
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lines[writeIndex] = line
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validLines[writeIndex] = true
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writeIndex = (writeIndex + 1) % maxJobLogLines
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}
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if err := scanner.Err(); err != nil {
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return "", 0, httpResp, fmt.Errorf("failed to read log content: %w", err)
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}
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var result []string
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linesInBuffer := totalLines
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if linesInBuffer > maxJobLogLines {
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linesInBuffer = maxJobLogLines
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}
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startIndex := 0
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if totalLines > maxJobLogLines {
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startIndex = writeIndex
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}
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for i := 0; i < linesInBuffer; i++ {
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idx := (startIndex + i) % maxJobLogLines
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if validLines[idx] {
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result = append(result, lines[idx])
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}
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}
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return strings.Join(result, "\n"), totalLines, httpResp, nil
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}
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