接下來，就讓我們看看forever能不能實現目標。
一、forever介紹
forever是一個簡單的命令式nodejs的守護進程，能夠啟動，停止，重啟App應用。 forever完全基於命令行操作，在forever進程之下，創建node的子進程，通過monitor監控node子進程的運行情況，一旦文件更新，或者進程掛掉，forever會自動重啟node服務器，確保應用正常運行。
二、forever安裝
全局安裝forever
複製代碼代碼如下:
~ D:/workspace/javascript>npm install -g forever
D:/toolkit/nodejs/forever -> D:/toolkit/nodejs/node_modules/forever/bin/forever
D:/toolkit/nodejs/foreverd -> D:/toolkit/nodejs/node_modules/forever/bin/foreverd
查看forever幫助
複製代碼代碼如下:
~ D:/workspace/javascript>forever -h
help: usage: forever [action] [options] SCRIPT [script-options]
help:
help: Monitors the script specified in the current process or as a daemon
help:
help: actions:
help: start Start SCRIPT as a daemon
help: stop Stop the daemon SCRIPT
help: stopall Stop all running forever scripts
help: restart Restart the daemon SCRIPT
help: restartall Restart all running forever scripts
help: list List all running forever scripts
help: config Lists all forever user configuration
help: set <key> <val> Sets the specified forever config <key>
help: clear <key> Clears the specified forever config <key>
help: logs Lists log files for all forever processes
help: logs <script|index> Tails the logs for <script|index>
help: columns add <col> Adds the specified column to the output in `forever list`
help: columns rm <col> Removed the specified column from the output in `forever list`
help: columns set <cols> Set all columns for the output in `forever list`
help: cleanlogs [CAREFUL] Deletes all historical forever log files
help:
help: options:
help: -m MAX Only run the specified script MAX times
help: -l LOGFILE Logs the forever output to LOGFILE
help: -o OUTFILE Logs stdout from child script to OUTFILE
help: -e ERRFILE Logs stderr from child script to ERRFILE
help: -p PATH Base path for all forever related files (pid files, etc.)
help: -c COMMAND COMMAND to execute (defaults to node)
help: -a, --append Append logs
help: -f, --fifo Stream logs to stdout
help: -n, --number Number of log lines to print
help: --pidFile The pid file
help: --sourceDir The source directory for which SCRIPT is relative to
help: --minUptime Minimum uptime (millis) for a script to not be considered "spinning"
help: --spinSleepTime Time to wait (millis) between launches of a spinning script.
help: --colors --no-colors will disable output coloring
help: --plain alias of --no-colors
help: -d, --debug Forces forever to log debug output
help: -v, --verbose Turns on the verbose messages from Forever
help: -s, --silent Run the child script silencing stdout and stderr
help: -w, --watch Watch for file changes
help: --watchDirectory Top-level directory to watch from
help: --watchIgnore To ignore pattern when watch is enabled (multiple option is allowed)
help: -h, --help You're staring at it
help:
help: [Long Running Process]
help: The forever process will continue to run outputting log messages to the console.
help: ex. forever -o out.log -e err.log my-script.js
help:
help: [Daemon]
help: The forever process will run as a daemon which will make the target process start
help: in the background. This is extremely useful for remote starting simple node.js scripts
help: without using nohup. It is recommended to run start with -o -l, & -e.
help: ex. forever start -l forever.log -o out.log -e err.log my-daemon.js
help: forever stop my-daemon.js
help:
我們看到forever支持的命令和配置項確實不少，應該是偏命令行的管理工具。
三、forever命令行的中文解釋
子命令actions：
複製代碼代碼如下:
start:啟動守護進程
stop:停止守護進程
stopall:停止所有的forever進程
restart:重啟守護進程
restartall:重啟所有的foever進程
list:列表顯示forever進程
config:列出所有的用戶配置項
set <key> <val>: 設置用戶配置項
clear <key>: 清楚用戶配置項
logs: 列出所有forever進程的日誌
logs <script|index>: 顯示最新的日誌
columns add <col>: 自定義指標到forever list
columns rm <col>: 刪除forever list的指標
columns set<cols>: 設置所有的指標到forever list
cleanlogs: 刪除所有的forever歷史日誌
配置參數options：
複製代碼代碼如下:
-m MAX: 運行指定腳本的次數
-l LOGFILE: 輸出日誌到LOGFILE
-o OUTFILE: 輸出控制台信息到OUTFILE
-e ERRFILE: 輸出控制台錯誤在ERRFILE
-p PATH: 根目錄
-c COMMAND: 執行命令，默認是node
-a, append: 合併日誌
-f, fifo: 流式日誌輸出
-n, number: 日誌打印行數
pidFile: pid文件
sourceDir: 源代碼目錄
minUptime: 最小spinn更新時間(ms)
spinSleepTime: 兩次spin間隔時間
colors: 控制台輸出著色
plain: no-colors的別名，控制台輸出無色
-d, debug: debug模式
-v, verbose: 打印詳細輸出
-s, silent: 不打印日誌和錯誤信息
-w, watch: 監控文件改變
watchDirectory: 監控頂級目錄
watchIgnore: 通過模式匹配忽略監控
-h, help: 命令行幫助信息
四、forever服務器管理
創建一個web項目(express3+ejs)，使用forever管理服務器。
安裝express3
複製代碼代碼如下:
~ D:/workspace/javascript>express -e nodejs-forever
~ D:/workspace/javascript>cd nodejs-forever && npm install
通過forever啟動應用
複製代碼代碼如下:
~ D:/workspace/javascript/nodejs-forever>forever start app.js
warn: --minUptime not set. Defaulting to: 1000ms
warn: --spinSleepTime not set. Your script will exit if it does not stay up for at least 1000ms
info: Forever processing file: app.js
打開瀏覽器: http://localhost:3000，可以看到web界面
在win下面查看forever狀態
複製代碼代碼如下:
~ D:/workspace/javascript/nodejs-forever>forever list
info: No forever processes running
~ D:/workspace/javascript/nodejs-forever>forever stop app.js
error: Forever cannot find process with index: app.js
我們發現forever的程序，工作不對了！ ！程序明明是運行狀態，通過list確看不到。接下來，切換成Linux Ubuntu繼續測試。
五、forever在Ubuntu進行服務器管理
Linux的系統環境
Linux: Ubuntu 12.04.2 64bit Server
Node: v0.11.2
Npm: 1.2.21
初始化項目：安裝命令不解釋了
複製代碼代碼如下:
~ cd /home/conan/nodejs
~ express -e nodejs-forever
~ cd nodejs-forever && npm install
~ sudo npm install forever -g
啟動forever
複製代碼代碼如下:~ forever start app.js
warn: --minUptime not set. Defaulting to: 1000ms
warn: --spinSleepTime not set. Your script will exit if it does not stay up for at least 1000ms
info: Forever processing file: app.js
查看node服務器狀態
複製代碼代碼如下:~ forever list
info: Forever processes running
data: uid command script forever pid logfile uptime
data: [0] L2tY /usr/local/bin/node app.js 18276 18279 /home/conan/.forever/L2tY.log 0:0:0:37.792
# 系統進程
~ ps -aux|grep node
Warning: bad ps syntax, perhaps a bogus '-'? See http://procps.sf.net/faq.html
conan 18296 0.5 1.1 597696 23776 ? Ssl 15:48 0:00 /usr/local/bin/node /usr/local/lib/node_modules/forever/bin/monitor app.js
conan 18299 0.4 0.8 630340 18392 ? Sl 15:48 0:00 /usr/local/bin/node /home/conan/nodejs/nodejs-forever/app.js
# 端口占用
~ netstat -nltp|grep node
tcp 0 0 0.0.0.0:3000 0.0.0.0:* LISTEN 18299/node
停止服務器
複製代碼代碼如下:~ forever stop app.js
info: Forever stopped process:
data: uid command script forever pid logfile uptime
[0] L2tY /usr/local/bin/node app.js 18276 18279 /home/conan/.forever/L2tY.log 0:0:0:45.621
我們看到在Linux Ubuntu環境中是正常的。
六、模擬服務器宕機
兩種測試方案：
1. 用Linux命令，直接殺死node進程
2. 在應用中，模擬異常退出
1). 用Linux命令，直接殺死node進程
複製代碼代碼如下:
# 查看node進程，PID=18299
~ ps -aux|grep node
conan 18296 0.0 1.1 597696 23776 ? Ssl 15:48 0:00 /usr/local/bin/node /usr/local/lib/node_modules/forever/bin/monitor app.js
conan 18299 0.0 0.8 630340 18392 ? Sl 15:48 0:00 /usr/local/bin/node /home/conan/nodejs/nodejs-forever/app.js
conan 18315 0.0 0.0 13584 956 pts/5 R+ 15:52 0:00 grep --color=auto node
# 殺死PID=19299
~ kill -9 18299
# 再看node進程，node自動重啟，新的PID=18324
~ ps -aux|grep node
conan 18296 0.0 1.1 597696 23916 ? Ssl 15:48 0:00 /usr/local/bin/node /usr/local/lib/node_modules/forever/bin/monitor app.js
conan 18316 2.6 0.8 630340 18412 ? Sl 15:52 0:00 /usr/local/bin/node /home/conan/nodejs/nodejs-forever/app.js
conan 18324 0.0 0.0 13584 956 pts/5 R+ 15:52 0:00 grep --color=auto node
我們看到看殺死node進程，forever會幫助我們，重啟node。
殺死forever的monitor
複製代碼代碼如下:
~ kill -9 18296
~ ps -aux|grep node
conan 18316 0.0 0.9 630340 18644 ? Sl 15:52 0:00 /usr/local/bin/node /home/conan/nodejs/nodejs-forever/app.js
conan 18333 0.0 0.0 13584 952 pts/5 S+ 15:57 0:00 grep --color=auto node
# 再殺死node進程
~ kill -9 18316
~ ps -aux|grep node
conan 18336 0.0 0.0 13584 956 pts/5 S+ 15:58 0:00 grep --color=auto node
我們嘗試殺死了forever的monitor，monitor程序沒有自動重啟，然後再殺死node進程後，node也不會自動重啟了。
2). 在應用中，模擬異常退出
修改文件：app.js
複製代碼代碼如下:
~ vi app.js
//..
http.createServer(app).listen(app.get('port'), function(){
console.log(new Date());
console.log('Express server listening on port ' + app.get('port'));
});
setTimeout(function(){
console.log(new Date());
throw new Error('App is error from inner!');
},10*1000);
通過node命令啟動
複製代碼代碼如下:~ node app.js
Thu Sep 26 2013 16:08:44 GMT+0800 (CST)
Express server listening on port 3000
Thu Sep 26 2013 16:08:54 GMT+0800 (CST)
/home/conan/nodejs/nodejs-forever/app.js:41
throw new Error('App is error from inner!');
^
Error: App is error from inner!
at null._onTimeout (/home/conan/nodejs/nodejs-forever/app.js:41:9)
at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
10秒後，由於內部錯誤， node進程掛掉了。
通過forever命令啟動
複製代碼代碼如下:
~ mkdir logs
~ chmod 777 -R logs
~ forever -p . -l ./logs/access.log -e ./logs/error.log start app.js
# 檢查錯誤日誌
~ cat logs/access.log ls
Thu Sep 26 2013 16:15:02 GMT+0800 (CST)
Express server listening on port 3000
Thu Sep 26 2013 16:15:12 GMT+0800 (CST)
/home/conan/nodejs/nodejs-forever/app.js:41
throw new Error('App is error from inner!');
^
Error: App is error from inner!
at null._onTimeout (/home/conan/nodejs/nodejs-forever/app.js:41:9)
at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
error: Forever detected script exited with code: 8
error: Forever restarting script for 1 time
Thu Sep 26 2013 16:15:13 GMT+0800 (CST)
Express server listening on port 3000
Thu Sep 26 2013 16:15:23 GMT+0800 (CST)
/home/conan/nodejs/nodejs-forever/app.js:41
throw new Error('App is error from inner!');
^
Error: App is error from inner!
at null._onTimeout (/home/conan/nodejs/nodejs-forever/app.js:41:9)
at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
error: Forever detected script exited with code: 8
error: Forever restarting script for 2 time
Thu Sep 26 2013 16:15:23 GMT+0800 (CST)
Express server listening on port 3000
Thu Sep 26 2013 16:15:33 GMT+0800 (CST)
/home/conan/nodejs/nodejs-forever/app.js:41
throw new Error('App is error from inner!');
^
Error: App is error from inner!
at null._onTimeout (/home/conan/nodejs/nodejs-forever/app.js:41:9)
at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
error: Forever detected script exited with code: 8
error: Forever restarting script for 3 time
Thu Sep 26 2013 16:15:33 GMT+0800 (CST)
Express server listening on port 3000
Thu Sep 26 2013 16:15:43 GMT+0800 (CST)
/home/conan/nodejs/nodejs-forever/app.js:41
throw new Error('App is error from inner!');
^
Error: App is error from inner!
at null._onTimeout (/home/conan/nodejs/nodejs-forever/app.js:41:9)
at Timer.listOnTimeout [as ontimeout] (timers.js:110:15)
error: Forever detected script exited with code: 8
error: Forever restarting script for 4 time
我們發現每10秒种，node內部掛掉，然後再被forever重啟！ ！
通過list我們手動刷新幾次也可以看到pid是變的。
複製代碼代碼如下:
~ forever list
info: Forever processes running
data: uid command script forever pid logfile uptime
data: [0] SmtT /usr/local/bin/node app.js 18444 18579 logs/access.log 0:0:0:7.211
~ forever list
info: Forever processes running
data: uid command script forever pid logfile uptime
data: [0] SmtT /usr/local/bin/node app.js 18444 18579 logs/access.log 0:0:0:8.921
~ forever list
info: Forever processes running
data: uid command script forever pid logfile uptime
data: [0] SmtT /usr/local/bin/node app.js 18444 18604 logs/access.log 0:0:0:0.177
~ forever list
info: Forever processes running
data: uid command script forever pid logfile uptime
data: [0] SmtT /usr/local/bin/node app.js 18444 18604 logs/access.log 0:0:0:2.206
這樣forever就幫助我們完成了，幾項比較重要服務器管理功能：“啟動/停止命令簡單”，“支持熱部署”，“宕機重啟”，“監控界面和日誌”。
比起upstart管理，省略了配置腳本的步驟(/etc/init/nodejs-xx.conf)。其他的功能，還要更近一步的使用才知道。
七、開發環境和生產環境的啟動配置
開發環境
複製代碼代碼如下:
~ cd /home/conan/nodejs/nodejs-forever/
~ forever -p . -l ./logs/access.log -e ./logs/error.log -a -w start app.js
生產環境
複製代碼代碼如下:~ export LOG=/var/log/nodejs/project
~ export PID=/var/log/nodejs/project/forever.pid
~ export APP_PATH=/home/conan/nodejs/nodejs-forever
~ export APP=$APP_PATH/app.js
~ forever -p $APP_PATH -l $LOG/access.log -e $LOG/error.log -o $LOG/out.log -a --pidFile $PID start $APP