case-sensitive text match with param q

mikebd · Oct 9, 2023 · 045950f · 045950f
1 parent 989f151
commit 045950f
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Showing 6 changed files with 135 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -13,13 +13,14 @@ Some assumptions could be considered TODO items for future enhancement
 * Log events are separated by a newline character
 * REST response Content-Type is text/plain; charset=utf-8, regardless of the Accept request header
 * All errors are returned to REST callers as HTTP status 500, even if these might be correctable by the caller
+* LRU result caching is not implemented
 
 ## Endpoints
 
 * `GET /api/v1/logs` - Get list of all log files in `/var/log` that this service can read
 * `GET /api/v1/logs/{log}` - Get the contents of the log file specified by `{log}` in `/var/log` (e.g. `/api/v1/logs/messages`)
   <br/>Query Parameters:
-  * `n` - Number of lines to return (default: 25)
+  * `n` - Number of lines to return (default: 25, all: 0)
   * `q` - Case sensitive fixed text filter to apply to each line (default: `""`), more performant than `r`
   * `r` - Regex filter to apply to each line (default: `.*`)
 

diff --git a/controller/rest/v1/logs.go b/controller/rest/v1/logs.go
@@ -27,9 +27,11 @@ func GetLog(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
 
 	logFilename := p.ByName("log")
 
+	textMatch := r.URL.Query().Get("q")
+
 	maxLines, _ := util.PositiveIntParamStrict(w, r, config.GetArguments().NumberOfLogLines, "n")
 	if maxLines > 0 {
-		logEvents, err := service.GetLog(config.LogDirectory, logFilename, maxLines)
+		logEvents, err := service.GetLog(config.LogDirectory, logFilename, textMatch, maxLines)
 
 		if err == nil {
 			// Reverse the slice - we want the most recent events first.

diff --git a/service/getLog.go b/service/getLog.go
@@ -7,7 +7,11 @@ import (
 )
 
 // GetLog returns the contents of a log file
-func GetLog(directoryPath string, filename string, maxLines int) ([]string, error) {
+// directoryPath: the path to the directory containing the log file
+// filename: the name of the log file
+// textMatch: a string to search for in the log file (case sensitive)
+// maxLines: the maximum number of lines to return
+func GetLog(directoryPath string, filename string, textMatch string, maxLines int) ([]string, error) {
 	filepath := strings.Join([]string{directoryPath, filename}, "/")
 
 	if !validLogFromName(directoryPath, filename) {
@@ -21,10 +25,23 @@ func GetLog(directoryPath string, filename string, maxLines int) ([]string, erro
 	}
 	result := strings.Split(string(byteSlice), "\n")
 
+	// Select lines that match the filters
+	if textMatch != "" {
+		filteredResult := make([]string, 0, len(result))
+		for i, line := range result {
+			if strings.Contains(line, textMatch) {
+				filteredResult = append(filteredResult, result[i])
+			}
+		}
+		result = filteredResult
+	}
+
 	// Restrict output to at most maxLines
-	endIndex := len(result) - 1
-	startIndex := max(0, endIndex-maxLines)
-	result = result[startIndex:endIndex]
+	if maxLines > 0 {
+		endIndex := len(result) - 1
+		startIndex := max(0, endIndex-maxLines)
+		result = result[startIndex:endIndex]
+	}
 
 	return result, nil
 }
diff --git a/service/getLog_test.go b/service/getLog_test.go
@@ -9,16 +9,32 @@ import (
 // Controllers may reverse the order as required by their clients.
 
 func ExampleGetLog_logDir1_10KiB_log() {
-	lines, _ := GetLog("testdata/logDir1", "10KiB.log", 2)
+	lines, _ := GetLog("testdata/logDir1", "10KiB.log", "", 2)
 	fmt.Println(strings.Join(lines, "\n"))
 	// Output:
 	// 2023-10-06T15:18:24.408740Z|info |olaret esanus ivo hey enug tewos ebad it u tuge po elora e iwemat o
 	// 2023-10-06T15:18:24.408762Z|debug|tucev uho e u ela opif ce igodeto hudegor ivosu ehab eaunopi balohan tagused gicefas
 }
 
+func ExampleGetLog_logDir1_99lines_log() {
+	lines, _ := GetLog("testdata/logDir1", "99lines.log", "9 ", 0)
+	fmt.Println(strings.Join(lines, "\n"))
+	// Output:
+	// line 9 yz
+	// line 19 yz
+	// line 29 yz
+	// line 39 yz
+	// line 49 yz
+	// line 59 yz
+	// line 69 yz
+	// line 79 yz
+	// line 89 yz
+	// line 99 yz
+}
+
 func ExampleGetLog_logDir1_1line_log() {
 	// Requesting more lines than available returns all available lines.
-	lines, _ := GetLog("testdata/logDir1", "1line.log", 10)
+	lines, _ := GetLog("testdata/logDir1", "1line.log", "", 10)
 	fmt.Println(strings.Join(lines, "\n"))
 	// Output:
 	// 2023-10-06T15:18:24.406350Z|debug|toyeni vate riwehu ato ped afe ral bo h redi esohet sir moyireh nema lidef

diff --git a/service/listLogs_test.go b/service/listLogs_test.go
@@ -7,5 +7,5 @@ import (
 func ExampleListLogs_logDir1() {
 	fmt.Println(ListLogs("testdata/logDir1"))
 	// Output:
-	// [10KiB.log 1line.log] <nil>
+	// [10KiB.log 1line.log 99lines.log] <nil>
 }
diff --git a/service/testdata/logDir1/99lines.log b/service/testdata/logDir1/99lines.log
@@ -0,0 +1,90 @@
+line 1 abc
+line 2 def
+line 3 ghi
+line 4 jkl
+line 5 mno
+line 6 pqr
+line 7 stu
+line 8 vwx
+line 9 yz
+line 11 abc
+line 12 def
+line 13 ghi
+line 14 jkl
+line 15 mno
+line 16 pqr
+line 17 stu
+line 18 vwx
+line 19 yz
+line 21 abc
+line 22 def
+line 23 ghi
+line 24 jkl
+line 25 mno
+line 26 pqr
+line 27 stu
+line 28 vwx
+line 29 yz
+line 31 abc
+line 32 def
+line 33 ghi
+line 34 jkl
+line 35 mno
+line 36 pqr
+line 37 stu
+line 38 vwx
+line 39 yz
+line 41 abc
+line 42 def
+line 43 ghi
+line 44 jkl
+line 45 mno
+line 46 pqr
+line 47 stu
+line 48 vwx
+line 49 yz
+line 51 abc
+line 52 def
+line 53 ghi
+line 54 jkl
+line 55 mno
+line 56 pqr
+line 57 stu
+line 58 vwx
+line 59 yz
+line 61 abc
+line 62 def
+line 63 ghi
+line 64 jkl
+line 65 mno
+line 66 pqr
+line 67 stu
+line 68 vwx
+line 69 yz
+line 71 abc
+line 72 def
+line 73 ghi
+line 74 jkl
+line 75 mno
+line 76 pqr
+line 77 stu
+line 78 vwx
+line 79 yz
+line 81 abc
+line 82 def
+line 83 ghi
+line 84 jkl
+line 85 mno
+line 86 pqr
+line 87 stu
+line 88 vwx
+line 89 yz
+line 91 abc
+line 92 def
+line 93 ghi
+line 94 jkl
+line 95 mno
+line 96 pqr
+line 97 stu
+line 98 vwx
+line 99 yz