Kai Hendry's other blog archives
For the last year (2013) Archlinux has been recommending users to use netctl to configure their network interfaces.
Netctl's ethernet-dhcp worked well, but not the wireless interface management which never made sense to me.
Upstream's Jouke Witteveen is sadly unhelpful despite my cries for help.
So on the back of systemd's (>210) systemd-networkd, which I previously blogged about when configuring my Droplet, I now have:
$ cat /etc/systemd/network/eth0.network
[Match]
Name=eth0
[Network]
DHCP=yes
Via journalctl -u systemd-networkd.service -f this seems to be able to detect
the carrier is on or off without ifplugd. Nice!
For your DNS nameservers, you need to symlink /etc/resolv.conf to /run/systemd/network/resolv.conf
etc$ sudo ln -s /run/systemd/network/resolv.conf
Wireless
To do all the WPA authentication stuff:
sudo systemctl enable wpa_supplicant@wlan0.service
You need to make sure /etc/wpa_supplicant/wpa_supplicant-wlan0.conf is in
place, as you can see in /usr/lib/systemd/system/wpa_supplicant@.service. I
prefer to link in /etc/wpa_supplicant.conf where I've also stored my wireless
passwords and things.
/etc/wpa_supplicant$ sudo ln -s /etc/wpa_supplicant.conf wpa_supplicant-wlan0.conf
Now to get the IP address, we use systemd-networkd, with the configuration:
$ cat /etc/systemd/network/wlan0.network
[Match]
Name=wlan0
[Network]
DHCP=yes
Wrap up
systemd-analyze for wlan0 is 3.203s and eth0 is 3.085s. I'm happy !
Currently I manually turn toggle wifi using my Thinkpad's wireless switch, for switching between wired and wireless interfaces.
Acknowledgements: WonderWoofy on the the Archlinux forums
From roughly systemd version 210, networking in my Droplet changed.
Out went netctl somehow (good riddance), and my network connectivity (uh oh).
Using Digital Ocean's buggy Console Access, I managed to setup my network access manually.
/etc/network.d/ethernet-static gave me the previous network settings:
[root@sgd ~]# cat /etc/network.d/ethernet-static
CONNECTION='ethernet'
INTERFACE='eth0'
IP='static'
ADDR='128.199.252.174'
NETMASK='255.255.192.0'
GATEWAY='128.199.192.1'
DNS=('8.8.4.4' '8.8.8.8' '209.244.0.3')
How to setup a networking interface with ip
I'm more familiar with ifconfig & route, but with some frantic Googling I
did figure out ip's odd unfamilar API:
ip addr add 128.199.252.174/255.255.192.0 dev enp0s3
ip route add default via 128.199.192.1
ip a then looks like:
[root@sgd ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 04:01:11:8d:89:01 brd ff:ff:ff:ff:ff:ff
inet 128.199.252.174/18 brd 128.199.255.255 scope global enp0s3
inet6 fe80::601:11ff:fe8d:8901/64 scope link
valid_lft forever preferred_lft forever
Sidenote: I'm not sure why my Droplet's network interface is called enp0s3 and not
something simple like eth0.
Ping to test... YES... I can ssh in.
Now to migrate to systemd-networkd.
I created /etc/systemd/network/enp0s3.network:
[root@sgd ~]# cat /etc/systemd/network/enp0s3.network
# Migrated from /etc/network.d/ethernet-static
# https://coreos.com/blog/intro-to-systemd-networkd/
[Match]
Name=enp0s3
[Network]
Address=128.199.252.174/18
Gateway=128.199.192.1
- To test
systemctl start systemd-networkd.service. Check
systemctl status systemd-networkd.servicelooks good[root@sgd ~]# systemctl status systemd-networkd.service systemd-networkd.service - Network Service Loaded: loaded (/usr/lib/systemd/system/systemd-networkd.service; enabled) Active: active (running) since Thu 2014-03-13 04:02:24 UTC; 11min ago Docs: man:systemd-networkd.service(8) Main PID: 158 (systemd-network) Status: "Processing requests..." CGroup: /system.slice/systemd-networkd.service `-158 /usr/lib/systemd/systemd-networkd Mar 13 04:02:24 sgd systemd-networkd[158]: enp0s3: link is up Mar 13 04:02:24 sgd systemd-networkd[158]: enp0s3: carrier on Mar 13 04:02:24 sgd systemd-networkd[158]: enp0s3: link configured Mar 13 04:02:24 sgd systemd[1]: Started Network Service.
To watch/tail what the systemd-networkd.service is doing, journalctl -u systemd-networkd.service -f
- Enable it
systemctl enable systemd-networkd.service - And reboot!
Loose ends, ifplugd
I noticed in htop ifplugd is running. I can't see from systemctl or pstree what invoked it. Mysterious.
[root@sgd ~]# ps aux | grep ifplugd
root 136 0.0 0.0 2200 284 ? Ss 04:02 0:00 /usr/bin/ifplugd -i enp0p3 -r /etc/ifplugd/netcfg.action -fIns
root 27388 0.0 0.1 2828 584 pts/1 S+ 04:16 0:00 grep ifplugd
Latest tips
Apache:
RewriteRule ^client/(.*)$ /client.php?id=$1 [L,QSA]
Nginx:
rewrite ^/client/(.*)$ /client.php?id=$1&$args last;
- Notice uris in nginx must start with /
- Notice &$args is needed to replicate Apache's
QSAfeature
Examples of how to populate a struct.
package main
import "fmt"
type event struct {
Name string
Date string
}
type events []event
func main() {
e1 := event{}
e1.Date = "Today"
e1.Name = "Somethiing"
e2 := event{Date: "Tomorrow", Name: "Dentist"}
s := events{e1, e2}
fmt.Printf("%+v\n", s)
}
For example.json:
{"menu": {
"id": "file",
"value": "File",
"popup": {
"menuitem": [
{"value": "New", "onclick": "CreateNewDoc()"},
{"value": "Open", "onclick": "OpenDoc()"},
{"value": "Close", "onclick": "CloseDoc()"}
]
}
}}
Desired output:
this.menu.popup.menuitem[0].value = "New"
this.menu.popup.menuitem[0].onclick = "CreateNewDoc()"
this.menu.popup.menuitem[1].value = "Open"
this.menu.popup.menuitem[1].onclick = "OpenDoc()"
this.menu.popup.menuitem[2].value = "Close"
this.menu.popup.menuitem[2].onclick = "CloseDoc()"
this.menu.value = "File"
this.menu.id = "file"
Python implementation
With thanks from Hyperair on Freenode's #hackerspace.sg
#!/usr/bin/python3
import json
import sys
fmt = '{key} = {value}'
def dump_obj(prefix, obj):
if isinstance(obj, dict):
for k, v in obj.items():
if prefix:
k = prefix + '.' + k
dump_obj(k, v)
elif isinstance(obj, list):
for i, v in enumerate(obj):
if prefix:
k = "{prefix}[{idx}]".format(prefix=prefix, idx=i)
dump_obj(k, v)
else:
print(fmt.format(key=prefix, value=json.dumps(obj)))
obj = json.loads(sys.stdin.read())
dump_obj('this', obj)
Golang implementation
Since Golang is statically typed, the important element in the code is t :=
x.(type) where they type of x gets asserted, which is a required step, so you
can then iterate over the resulting structure.
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"strconv"
)
func dumpobj(prefix string, x interface{}) {
switch t := x.(type) {
case map[string]interface{}:
for k, v := range t {
dumpobj(prefix+"."+k, v)
}
case []interface{}:
for i, v := range t {
dumpobj(prefix+"["+strconv.Itoa(i)+"]", v)
}
case string:
fmt.Printf("%s = %q\n", prefix, t)
default:
fmt.Printf("Unhandled: %T\n", t)
}
}
func main() {
j, err := ioutil.ReadAll(os.Stdin)
if err != nil {
panic(err)
}
var pj interface{}
err = json.Unmarshal(j, &pj)
if err != nil {
panic(err)
}
dumpobj("this", pj)
}
Alternative example with depth: http://play.golang.org/p/QOwxJQ4z4Z
Source is with thanks again from dsal from #go-nuts http://play.golang.org/p/pt4MLJ6HcV
However ideally you know the JSON structure beforehand, and you create a structure for it to map to, e.g. http://play.golang.org/p/bdjC6DLTqo. Only then you can access values easily like:
fmt.Println(myOb.Menu.Popup.Menuitem[0].Value)
http://wiki2.dovecot.org/HowTo/ReadOnlyArchive is outdated.
/etc/dovecot/dovecot.conf
$ sudo doveconf -n
# 2.2.9: /etc/dovecot/dovecot.conf
# OS: Linux 3.9.4-1-ARCH x86_64
auth_mechanisms = plain anonymous
log_path = /home/example/readonly/dovecot.log
mail_location = Maildir:~/mail/inbox
mail_log_prefix = %Us(%r):
passdb {
args = /etc/anon.passwd
driver = passwd-file
}
service auth {
user = nobody
}
ssl = no
userdb {
args = /etc/anon.passwd
driver = passwd-file
}
valid_chroot_dirs = /home/example/readonly
For debugging purposes, tail /home/example/readonly/dovecot.log
/etc/anon.passwd
anonymous:{PLAIN}:501:501::/home/example/readonly/::nopassword=1
/home/example/readonly
Permissions are important. You will be doing sudo chown -R 501:501 .
$ tree -ugp readonly
readonly
|-- [-rw-r--r-- root root ] dovecot.conf
|-- [-rw------- 501 501 ] dovecot.log
`-- [dr-xr-xr-x 501 501 ] mail
`-- [drwxr-xr-x 501 501 ] inbox
|-- [dr-xr-xr-x 501 501 ] cur
| |-- [-r--r--r-- 501 501 ] 1386050966.M540929P13587.sg.webconverger.com,S=315,W=328:2,S
| |-- [-r--r--r-- 501 501 ] 1386051008.M248603P13703.sg.webconverger.com,S=2081,W=2125:2,RS
| |-- [-r--r--r-- 501 501 ] 1386051093.M840486P13614.sg.webconverger.com,S=694,W=711:2,S
| |-- [-r--r--r-- 501 501 ] 1386051118.M789320P13725.sg.webconverger.com,S=2084,W=2127:2,S
| `-- [-r--r--r-- 501 501 ] 1386051172.M378951P13760.sg.webconverger.com,S=1881,W=1920:2,S
|-- [-rw-r--r-- 501 501 ] dovecot-uidlist
|-- [-rw-r--r-- 501 501 ] dovecot-uidvalidity
|-- [-rw-r--r-- 501 501 ] dovecot-uidvalidity.529d7573
|-- [-rw-r--r-- 501 501 ] dovecot.index.cache
|-- [-rw-r--r-- 501 501 ] dovecot.index.log
|-- [-rw-r--r-- 501 501 ] dovecot.index.thread
|-- [-r--r--r-- 501 501 ] inbox
|-- [dr-xr-xr-x 501 501 ] new
`-- [dr-xr-xr-x 501 501 ] tmp
5 directories, 14 files
.muttrc test
$ cat mutt-econv-test
set spoolfile=imap://anonymous@imap.dabase.com
set folder=imap://anonymous@imap.dabase.com
set sort=threads
set sort_aux=reverse-last-date-received
To test:
$ mutt -F mutt-econv-test
See https://github.com/kaihendry/econversations for why am I doing this.
Tag the thread and (s)ave or (f)orward it
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