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I am writing a C++ program and wish to determine the status of a HAAst peer. How should I get this information from HAAst?
The best way to communicate programmatically with HAAst is through the socket interface. When haast is running it creates a socket in the directory /var/run. This socket looks and acts just like a regular file; you can write to the file and read from the file to command HAAst and gather status information.
To retrieve the status of the cluster via the socket interface, use the ‘getstatus’ command. The pseudocode to do so is as follows:
Open file /var/run/haast.sock as read+write
Read ‘ready>’ prompt from file
Optionally write command ID and newline to file, e.g. ‘id: 123n’
Write get status command and newline to file, e.g. ‘command:getstatus\n\n’
Read response from file
Close file
Parse response
The ID sent can be any string (to uniquely identify the response) but is optional. In general we recommend sending an auto-incremented counter. Once all required parameters (of this command) have been sent, send a second newline (i.e. 2 sequential newline characters) to tell HAAst the command is complete and ready for processing.
The following is the actual output (read) in red color, and input (written) in blue color, from the above pseudo code:
haast socket interface v1.1 ready>id: 123 command:getstatus id: 123 result: ok cluster name: Telium cluster start time: 1459816998033 cluster start time formatted: Mon Apr 4 20:43:18 2016 cluster run duration: 12404571 cluster run duration formatted: 71 days, 13 hours, 42 minutes, 51 seconds cluster fail over count: 79 local peer name: PBX1 in Waterloo data center wall local haast state: 4 local haast state formatted: Active local peer health state: 1 local peer health state formatted: Normal local asterisk state: 2 local asterisk state formatted: Started local asterisk connection state: 7 local asterisk connection state formatted: Logged in local start time: 1464643147663 local start time formatted: Mon May 30 17:19:07 2016 local haast run duration: 2740022 local haast run duration formatted: 15 days, 17 hours, 7 minutes, 2 seconds local fail over count: 11 local previous fail over timestamp: 1465102805740 local previous fail over timestamp formatted: Sun Jun 5 01:00:05 2016 local previous fail over cause: 2 local previous fail over cause formatted: Dual standby peer contention detected local previous haast state: 3 local previous haast state formatted: Standby local to remote peerlink connection state: 7 local to remote peerlink connection state formatted: Up remote data available: 1 remote peer name: PBX2 VM in Mississauga data center remote haast state: 3 remote haast state formatted: Standby remote peer health state: 1 remote peer health state formatted: Normal remote asterisk state: 4 remote asterisk state formatted: Stopped remote asterisk connection state: 4 remote asterisk connection state formatted: Connect failed remote start time: 1464643407951 remote start time formatted: Mon May 30 17:23:27 2016 remote haast run duration: 2739761 remote haast run duration formatted: 15 days, 17 hours, 2 minutes, 41 seconds remote fail over count: 8 remote previous fail over timestamp: 1465102804675 remote previous fail over timestamp formatted: Sun Jun 5 01:00:04 2016 remote previous fail over cause: 23 remote previous fail over cause formatted: Local peer automatic demotion request remote previous haast state: 4 remote previous haast state formatted: Active remote to local peerlink connection state: 7 remote to local peerlink connection state formatted: Up ready>To learn how to use the HAAst socket interface you can use the ‘socat’ command to interact with the HAAst socket from a Bash command line. (You may need to add the socat command / package to your particular Linux installation). The exact syntax for the socat command is as follows:
socat – UNIX-CONNECT:/var/run/haast.sock
You can then send any invalid command (eg: XXXX) and HAAst will respond with a list of valid commands.
To help customers trying to extract status information, here is a sample python script that retrieves and prints the local status:
# Example python script to retrieve local HAAst status
import socket
import sys
# End of packet marker
READYPROMPT=’ready>’
# Create a UDS socket
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
# Connect the socket to the port where the server is listening
server_address = ‘/run/haast.sock’
try:
sock.connect(server_address)
except socket.error, msg:
print >>sys.stderr, msg
sys.exit(1)
# Wait for a packet
def receivepacket():
global sock
total_data=[];data=”
while True:
data=sock.recv(8192)
if READYPROMPT in data:
total_data.append(data[:data.find(READYPROMPT)])
break
total_data.append(data)
if len(total_data)>2:
#check if end_of_data was split
last_pair=total_data[-2]+total_data[-1]
if READYPROMPT in last_pair:
total_data[-2]=last_pair[:last_pair.find(READYPROMPT)]
total_data.pop()
break
return ”.join(total_data).replace(‘r’,”).replace(‘nn’,’n’)
# Send a packet
def sendpacket(message):
global sock
success = 1
try:
# Send data
message += ‘nn’
# print >>sys.stderr, ‘sending “%s”‘%message
sock.sendall(message)
amount_received = 0
amount_expected = len(message)
while amount_received < amount_expected: data = sock.recv(16) amount_received += len(data) finally: # print >>sys.stderr, ‘closing socket’
# sock.close()
success = 0
return success
got = receivepacket()
sendpacket(“id:123ncommand:getstatus”)
got = receivepacket()
for item in got.split(“n”):
if “local haast state formatted:” in item:
print item.strip()
sock.close()
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