Added log library tests and implementation

tieto-cpu-tracker/lib/log/CMakeLists.txt

@@ -1 +1,24 @@
 cmake_minimum_required(VERSION 3.5)
+
+project(log LANGUAGES C VERSION 0.1.0)
+
+set(C_STANDARD 11)
+set(TARGET ${PROJECT_NAME})
+
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
+add_library(${TARGET}
+  src/Log.c
+  )
+
+target_include_directories(${TARGET}
+  PRIVATE
+  src
+  PUBLIC
+  include
+  )
+
+if (${BUILD_TESTS})
+  add_subdirectory(tests/integration)
+endif()
+

tieto-cpu-tracker/lib/log/include/log/Log.h

@@ -0,0 +1,12 @@
+#ifndef LOG_H
+#define LOG_H
+
+void initLogger(const char* logfile);
+
+void clearLogs(void);
+
+void writeLog(const char* tag, const char* format, ...);
+
+void closeLogger(void);
+
+#endif // LOG_H

tieto-cpu-tracker/lib/log/src/Log.c

@@ -0,0 +1,62 @@
+#include "log/Log.h"
+
+#include <string.h>
+#include <time.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#define LOG_FILE_PATH_MAX 256
+// #define LOG_LINE_MAX 256
+
+static FILE* logFile = NULL;
+static char logFilePath[LOG_FILE_PATH_MAX];
+
+void initLogger(const char* logfile)
+{
+  strcpy(logFilePath, logfile);
+  if (logFile != NULL) {
+    fclose(logFile);
+  }
+  logFile = fopen(logFilePath, "a");
+  if (logFile == NULL) {
+      fprintf(stderr, "Unable to open logfile\n");
+  }
+}
+
+void clearLogs(void)
+{
+  if (logFile != NULL) {
+    closeLogger();
+  }
+  if (remove(logFilePath) != 0) {
+    fprintf(stderr, "Unable to remove logfile\n");
+  }
+  initLogger(logFilePath);
+}
+
+__attribute__((__format__ (__printf__, 2, 0)))
+void writeLog(const char* tag, const char* format, ...)
+{
+  time_t now = time(NULL);
+  struct tm* timeinfo = localtime(&now);
+  char timestamp[20];
+  va_list args;
+
+  strftime(timestamp, sizeof(timestamp), "%Y-%m-%d %H:%M:%S", timeinfo);
+  
+  va_start(args, format);
+  fprintf(logFile, "%s %s ", timestamp, tag);
+  vfprintf(logFile, format, args);
+  fprintf(logFile, "\n");
+  va_end(args);
+
+  fflush(logFile);
+}
+
+void closeLogger(void)
+{
+  if (logFile != NULL) {
+    fclose(logFile);
+    logFile = NULL;
+  }
+}

tieto-cpu-tracker/lib/log/tests/integration/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.5)
+
+set(C_STANDARD 11)
+enable_testing()
+
+set(SRC_DIR ../../src)
+
+include_directories(${SRC_DIR})
+
+add_executable(LogTest Log.test.c)
+target_link_libraries(LogTest log)
+add_test(LogTest ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/LogTest)

tieto-cpu-tracker/lib/log/tests/integration/Log.test.c

@@ -0,0 +1,54 @@
+#include "log/Log.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <assert.h>
+
+#define TAG "TEST"
+
+static const char* LOG_FILE = "/tmp/log-test.log";
+
+static int countLines(const char* filePath) {
+  int count = 0;
+  int ch;
+  FILE* file = fopen(filePath, "r");
+  if (file == NULL) {
+      return -1;
+  }
+  while ((ch = fgetc(file)) != EOF) {
+      if (ch == '\n') {
+          count++;
+      }
+  }
+  fclose(file);
+  return count;
+}
+
+
+int main(void)
+{
+  int lineCount = 0;
+
+  initLogger(LOG_FILE);
+  clearLogs();
+  
+  lineCount = countLines(LOG_FILE);
+  assert(lineCount == 0);
+  
+  writeLog(TAG, "First log message");
+  writeLog(TAG, "Second log message");
+  writeLog(TAG, "Third log message");
+  
+  lineCount = countLines(LOG_FILE);
+  assert(lineCount == 3);
+
+  writeLog(TAG, "This is %ith line that is %s", 4, "formatted");
+
+  lineCount = countLines(LOG_FILE);
+  assert(lineCount == 4);
+
+  closeLogger();
+
+  printf("Log file %s contains %d lines\n", LOG_FILE, lineCount);
+  return 0;
+}