101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"fmt"
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"sort"
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"strconv"
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"strings"
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)
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// result stores details about a log line
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type result struct {
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domain string
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visits int
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// add more metrics when needed
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}
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// parser keep tracks of the parsing
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type parser struct {
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sum map[string]result // metrics per domain
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domains []string // unique domain names
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total int // total visits for all domains
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lines int // number of parsed lines (for the error messages)
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lerr error // the last error occurred
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}
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// newParser creates and returns a new parser
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func newParser() *parser {
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return &parser{sum: make(map[string]result)}
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}
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// parse result from a log line
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func (p *parser) parse(line string) (r result) {
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if p.lerr != nil {
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return
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}
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p.lines++
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fields := strings.Fields(line)
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if len(fields) != 2 {
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p.lerr = fmt.Errorf("wrong input: %v (line #%d)", fields, p.lines)
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return
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}
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var err error
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r.domain = fields[0]
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r.visits, err = strconv.Atoi(fields[1])
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if r.visits < 0 || err != nil {
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p.lerr = fmt.Errorf("wrong input: %q (line #%d)", fields[1], p.lines)
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}
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return
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}
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// update the parsing results
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func (p *parser) update(r result) {
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if p.lerr != nil {
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return
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}
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// collect unique domains for easy access to sum map
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if _, ok := p.sum[r.domain]; !ok {
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p.domains = append(p.domains, r.domain)
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}
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// keep track of total visits
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p.total += r.visits
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// group the log lines by domain
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p.sum[r.domain] = result{
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domain: r.domain,
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visits: r.visits + p.sum[r.domain].visits,
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}
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}
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// summarize the parsing results
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func (p *parser) summarize() {
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sort.Strings(p.domains)
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fmt.Printf("%-30s %10s\n", "DOMAIN", "VISITS")
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fmt.Println(strings.Repeat("-", 45))
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for _, domain := range p.domains {
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fmt.Printf("%-30s %10d\n", domain, p.sum[domain].visits)
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}
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fmt.Printf("\n%-30s %10d\n", "TOTAL", p.total)
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}
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// err returns the last error encountered
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func (p *parser) err() error {
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return p.lerr
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}
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