#launchdaemon

[michaelfeurstein]

LaunchDaemons & LaunchAgents

a short note on handling LaunchDaemons and LaunchAgents on your Mac environment. 

What do they do: It’s a service/program/script running in the background based on specific parameters it may restart automatically, do things on a regular basis or simply start and stop servers, databases and the likes. Where are they: /Library/LaunchDaemons /Library/LaunchAgents /Systems/Library/LaunchDaemons /System/Library/LaunchAgents

What’s the difference: A LaunchDaemon is run by the root user or the user specified in UserName. A LaunchAgent is run by the currently logged in user.

System Integrity Protection: With El Capitan, Apple introduced System Integrity Protection, as a security measure to protect files and folders on your Mac - specifically those in the root directory.

This means that when working with LaunchDaemons or LaunchAgents you will need to keep them under /Library/LaunchDaemons or /Library/LaunchAgents

Here’s a working example for a LaunchAgent I use to start NaviServer:

<?xml version=“1.0” encoding=“UTF-8”?> <!DOCTYPE plist PUBLIC “-//Apple Computer//DTD PLIST 1.0//EN” “http://www.apple.com/DTDs/PropertyList-1.0.dtd”><plist version=“1.0”>   <dict> <key>Label</key> <string>org.naviserver</string> <key>ProgramArguments</key> <array> <string>/usr/local/ns/bin/nsd</string> <string>-f</string> <string>-u</string> <string>nsadmin</string> <string>-g</string> <string>nsadmin</string> <string>-t</string> <string>/usr/local/ns/conf/nsd-config.tcl</string> </array> <key>StandardOutPath</key>           <string>/usr/local/var/log/naviserver_daemon.log</string>       <key>StandardErrorPath</key>           <string>/usr/local/var/log/naviserver_daemon.log</string> </dict> </plist>

The file is saved under /Library/LaunchAgents/org.naviserver.plist

Load the LaunchAgent:

sudo launchctl load org.naviserver.plist

Start the LaunchAgent:

sudo launchctl start org.naviserver

Note the different input values for loading and starting through launchctl. The start command only takes the Label as an input.

Stop the LaunchAgent:

sudo launchctl stop org.naviserver

Unload the LaunchAgent:

sudo launchctl unload org.naviserver.plist

Some useful links:

Launchd Info: http://launchd.info/

System Integrity Protection (SIP) https://support.apple.com/en-us/HT204899

Note on running navisever in foreground mode through LaunchDaemon: http://superuser.com/a/1112872/311059 (Thanks for this one)

Technical Note TN2083 from the Apple Developer Library: https://developer.apple.com/library/mac/technotes/tn2083/_index.html

[michaelfeurstein]

Part 2 - Configuring your NaviServer on Mac OS

A Step by Step Guide to further setup your fresh NaviServer install.

Part 1 - Getting Started: Installing NaviServer on MacOS Part 2 - Configuring your NaviServer on Mac OS Part 3 - A simple helloworld database interaction Part 4 - Setting up OpenACS with NaviServer on MacOS

What I will cover in this part:

(A) Configuring your LaunchDaemons to start and stop NaviServer and PostgreSQL (B) Setup your new database environment (C) Configuring NaviServer to work with PostgreSQL

================================================== Step (A) Conf(ront)(igur)ing your LaunchDaemons ==================================================

Some general concerns on designing integrated high quality linux applications.

One could use daemontools. However I did not get it to work on my Mac environment so I chose to stick with what Apple suggests: LaunchDaemon. If you still prefer daemontools maybe this example writeup will help you get started.

(1) Read up on what a LaunchDaemon is

This tutorial on launchd http://launchd.info/ gives a nice overview. Over at openacs.org some NaviServer related example LaunchDaemons already exist. If you still need more information this post is quite informative. Last but not least you can always consult Apple's mega documentation if in doubt.

(2) Create a LaunchDaemon for NaviServer

Navigate to:

/System/Library/LaunchDaemons

Create a file called:

org.naviserver.yourname.plist

Insert the following:

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0">    <dict>        <key>Label</key>        <string>org.naviserver.yourname</string>        <key>ProgramArguments</key>        <array>                <string>/usr/local/ns/bin/nsd</string>                <string>-f</string>                <string>-u</string>                <string>nsadmin</string>                <string>-g</string>                <string>nsadmin</string>                <string>-t</string>                <string>/usr/local/ns/conf/nsd-config.tcl</string>        </array>        <key>KeepAlive</key>        <false/>        <key>StandardOutPath</key>        <string>/usr/local/var/log/naviserver_daemon.log</string>        <key>StandardErrorPath</key>        <string>/usr/local/var/log/naviserver_daemon.log</string>    </dict> </plist>

Explanations:

Label is the key to identify this LaunchDaemon = org.naviserver.yourname

ProgramArguments contains an array of strings with the actual command to start NaviServer. Note that you need to add each parameter and value separately. Also, pay attention to add the foreground flag in order for launchd to see the process (backgroundinfo: http://superuser.com/a/1112872/311059) 

I also define a StandardOutPath and StandardErrorPath feeding into /var/log/naviserver.log in order to keep track of dubious Daemon messages.

(3) Work with launchctl to list, load/unload, start/stop NaviServer Note the different input paramaters for load/unload and start/stop.

sudo launchctl list | grep ‘yourname’ sudo launchctl unload org.naviserver.yourname.plist sudo launchctl load org.naviserver.yourname.plist sudo launchctl start org.naviserver.yourname sudo launchctl stop org.naviserver.yourname

================================================== Step (B) Setup your new database environment ==================================================

(0) Where is what

psql binaries such as psql itself, createdb, dropdb etc are located here:

/opt/local/lib/postgresql94/bin/

which psql94 should give you sth like this

/opt/local/bin/psql94

psql94 points to psql in the postgresql94 bin directory

/opt/local/bin/psql94 -> /opt/local/lib/postgresql94/bin/psql

(1) Create a database cluster with initdb

sudo mkdir -p /opt/local/var/db/postgresql94/defaultdb sudo chown postgres:postgres /opt/local/var/db/postgresql94/defaultdb sudo su postgres -c '/opt/local/lib/postgresql94/bin/initdb -D /opt/local/var/db/postgresql94/defaultdb'

or

sudo su postgres /opt/local/lib/postgresql94/bin/initdb -D /opt/local/var/db/postgresql94/defaultdb

(2) Check on the configuration file

sudo vi /opt/local/var/db/postgresql94/defaultdb/postgresql.conf

(3) Turn some things on

autovacuum = on track_counts = on default_with_oids = on

(4) Start the PSQL server manually and ensure functionality

sudo su postgres -c '/opt/local/lib/postgresql94/bin/postgres -D /opt/local/var/db/postgresql94/defaultdb' &

or

sudo su postgres -c '/opt/local/lib/postgresql94/bin/pg_ctl -D /opt/local/var/db/postgresql94/defaultdb -l logfile start' &

(5) Add user postgres to nsadmin group

sudo /usr/sbin/dseditgroup -v -o edit -a postgres -t user nsadmin

(6) Create your database user For ease of use I prefer to create the same user I use for my system.

/opt/local/lib/postgresql94/bin/createuser -U postgres yourUserName /opt/local/lib/postgresql94/bin/createdb -U postgres testdb /opt/local/lib/postgresql94/bin/psql testdb

(7) Setup a LaunchDaemon in /System/Library/LaunchDaemons

Navigate to:

/Library/LaunchDaemons

Create a file called:

org.postgresql.yourname.plist

Insert the following:

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0">    <dict>        <key>Label</key>        <string>org.postgresql.mifeurst</string>        <key>UserName</key>        <string>postgres</string>        <key>GroupName</key>        <string>nsadmin</string>        <key>ProgramArguments</key>        <array>                <string>/opt/local/lib/postgresql94/bin/postgres</string>                <string>-D</string>                <string>/opt/local/var/db/postgresql94/defaultdb</string>        </array>        <key>StandardOutPath</key>        <string>/usr/local/var/log/postgresql_daemon.log</string>        <key>StandardErrorPath</key>        <string>/usr/local/var/log/postgresql_daemon.log</string>    </dict> </plist>

(8) Ensure that the var log is writable for the postgres user This can be particularly frustrating as the LaunchDaemon will through the following error in /var/log/system.log: Service could not initialize: 15G31

sudo touch /usr/local/var/log/postgresql_daemon.log sudo chown postgres:postgres /usr/local/var/log/postgresql_daemon.log

(9) Work with launchctl to list, load/unload, start/stop PostgreSQL

sudo launchctl list | grep ‘yourname’ sudo launchctl unload org.postgresql.yourname.plist sudo launchctl load org.postgresql.yourname.plist sudo launchctl start org.postgresql.yourname sudo launchctl stop org.postgresql.yourname

You should now see something like this:

For superuser access login with postgres user (note the hash on the prompt):

psql94 -U postgres testdb

Drop the database if you don’t want it anymore. with drodb.

================================================== Step (C) Configuring NaviServer to work with PostgreSQL ==================================================

For a successful database connection ensure the following setup for your conf.tcl file:

set db_host     localhost set db_port     "5432" set db_user     yourUsername set db_name     testdb

ns_section     "ns/db/drivers" ns_param       postgres           nsdbpg.so

ns_section     "ns/db/pools" ns_param       pool1           "PostgresSQL Database Pool"

ns_section     "ns/db/pool/pool1" ns_param        driver              postgres                           ns_param        connections         64                                 ns_param        user                ${db_user}                         ns_param        password            ""     ns_param        datasource          ${db_host}:${db_port}:${db_name}   ns_param        pgbin               /opt/local/lib/postgresql94/bin/   ns_param        verbose             On     ns_param        logsqlerrors        On     ns_param        extendedtableinfo   On                                 ns_param        maxidle             31536000 ns_param        maxopen             31536000

ns_section     "ns/server/default/db" ns_param        pools               *       ns_param        defaultpool         pool1

Now you are good to go for part 3 covering a simple helloWorld integration demonstrating a database interaction.