1 files changed, 97 insertions, 0 deletions
diff --git a/src/lib/logger.js b/src/lib/logger.js
new file mode 100644
index 0000000..260ba41
--- /dev/null
+++ b/src/lib/logger.js
@@ -0,0 +1,97 @@
+const log4js = require('log4js')
+const fs = require('fs/promises')
+const fsConstants = require('fs').constants
+const util = require('src/lib/util')
+
+module.exports = {
+    /**
+     * @param {string} file
+     * @param {string} levelFile
+     * @param {string} levelConsole
+     */
+    async init({file, levelFile, levelConsole}) {
+        const categories = {
+            default: {
+                appenders: ['stdout-filter'],
+                level: 'trace'
+            }
+        }
+
+        const appenders = {
+            stdout: {
+                type: 'stdout',
+                level: 'trace'
+            },
+            'stdout-filter': {
+                type: 'logLevelFilter',
+                appender: 'stdout',
+                level: levelConsole
+            }
+        }
+
+        if (file) {
+            let exists
+            try {
+                await fs.stat(file)
+                exists = true
+            } catch (error) {
+                exists = false
+            }
+
+            // if file exists
+            if (exists) {
+                // see if it's writable
+                try {
+                    // this promise fullfills with undefined upon success
+                    await fs.access(file, fsConstants.W_OK)
+                } catch (error) {
+                    throw new Error(`file '${file}' is not writable:` + error.message)
+                }
+            } else {
+                // try to create an empty file
+                let fd
+                try {
+                    fd = await fs.open(file, 'wx')
+                } catch (error) {
+                    throw new Error(`failed to create file '${file}': ` + error.message)
+                } finally {
+                    await fd?.close()
+                }
+            }
+
+            categories.default.appenders.push('file-filter')
+            appenders.file = {
+                type: 'file',
+                filename: file,
+                maxLogSize: 1024 * 1024 * 50,
+                debug: 'debug'
+            }
+            appenders['file-filter'] = {
+                type: 'logLevelFilter',
+                appender: 'file',
+                level: levelFile
+            }
+        }
+
+        log4js.configure({
+            appenders,
+            categories
+        })
+    },
+
+    /**
+     * @return {Logger}
+     */
+    getLogger(...args) {
+        return log4js.getLogger(...args)
+    },
+
+    /**
+     * @param cb
+     */
+    shutdown(cb) {
+        log4js.shutdown(cb)
+    },
+
+    Logger: log4js.Logger,
+}