AUM是App Usage Metrics的缩写，用于统计FFOS中一些应用的使用情况，并且在用户允许的情况下(Settings中设置)，将统计信息上报Telemetry Server。
1. AUM会监控FFOS中的几种应用。
- Apps pre-installed with the phone (certified, or using a gaia origin)
- Apps installed from the marketplace
2. Telemetry Server Path
http://{host}:{port}/{deviceID}/{reason}/{appName}/{appVersion}/{appUpdateChannel}/{appBuildID}
3. AUM消息格式
以下是讲flame手机中的AUM功能打开，添加log打印出来的消息格式。
{ "ver":1, "info":{ "start":1437968681114, "apps":{ }, "searches":{ }, "stop":1437968928832, "deviceID":"7a0f9f11-c8de-421d-939b-878b7e89915e", "locale":"en-US", "screen":{ "width":320, "height":569, "devicePixelRatio":1.5 }, "deviceinfo":{ "developer.menu.enabled":true, "deviceinfo.hardware":"qcom", "deviceinfo.os":"2.5.0.0-prerelease", "deviceinfo.product_model":"flame", "deviceinfo.software":"Boot2Gecko 2.5.0.0-prerelease" }, "simInfo":{ "network":null, "icc":null }, "reason":"appusage", "appName":"FirefoxOS", "appUpdateChannel":"nightly", "appBuildID":"20150723141330", "appVersion":"42.0a1" } }
info->apps字段是关于per-app的信息，参考代码，其消息格式是:
{ "per-app-manifestURL-1":{ "yyyymmdd":{ "usageTime":0, "invocations":0, "installs":0, "uninstalls":0, "activities":{ } } }, "per-app-manifestURL-2":{ "yyyymmdd":{ "usageTime":0, "invocations":0, "installs":0, "uninstalls":0, "activities":{ } } } }
info->searches字段是关于per-search的信息，参考代码，其消息格式是:
{ "per-app-provider-1":{ "yyyymmdd":{ "count":0 } }, "per-app-provider-2":{ "yyyymmdd":{ "count":0 } } }
4. AUM upload policy
FFOS中预设的是2 weeks upload。
5. code分析
代码比较简单，以后有时间再贴出详细分析(代码位置:gaia/apps/system/js/app_usage_metrics.js)。