feat(log): support env var LOG_LEVEL

@xen-orchestra/log/src/configure.js

@@ -51,11 +51,12 @@ const symbol =
     ? Symbol.for('@xen-orchestra/log')
     : '@@@xen-orchestra/log'
 
+const { env } = process
 global[symbol] = createTransport({
   // display warnings or above, and all that are enabled via DEBUG or
   // NODE_DEBUG env
-  filter: process.env.DEBUG || process.env.NODE_DEBUG,
-  level: LEVELS.INFO,
+  filter: env.DEBUG || env.NODE_DEBUG,
+  level: resolve(env.LOG_LEVEL, LEVELS.INFO),
 
   transport: createConsoleTransport(),
 })

@xen-orchestra/log/src/index.js

@@ -1,5 +1,5 @@
 import createTransport from './transports/console'
-import LEVELS from './levels'
+import LEVELS, { resolve } from './levels'
 
 const symbol =
   typeof Symbol !== 'undefined'
@@ -9,7 +9,8 @@ if (!(symbol in global)) {
   // the default behavior, without requiring `configure` is to avoid
   // logging anything unless it's a real error
   const transport = createTransport()
-  global[symbol] = log => log.level > LEVELS.WARN && transport(log)
+  const level = resolve(process.env.LOG_LEVEL, LEVELS.WARN)
+  global[symbol] = log => log.level >= level && transport(log)
 }
 
 // -------------------------------------------------------------------

@xen-orchestra/log/src/levels.js

@@ -13,11 +13,22 @@ for (const name in LEVELS) {
   NAMES[LEVELS[name]] = name
 }
 
-export const resolve = level => {
-  if (typeof level === 'string') {
-    level = LEVELS[level.toUpperCase()]
+// resolves to the number representation of a level
+//
+// returns `defaultLevel` if invalid
+export const resolve = (level, defaultLevel) => {
+  const type = typeof level
+  if (type === 'number') {
+    if (level in NAMES) {
+      return level
+    }
+  } else if (type === 'string') {
+    const nLevel = LEVELS[level.toUpperCase()]
+    if (nLevel !== undefined) {
+      return nLevel
+    }
   }
-  return level
+  return defaultLevel
 }
 
 Object.freeze(LEVELS)