tpq 1.7

python库的使用

数据库连接信息可以通过库api提供。

importtpq# Explicitly provide database connection informationq=tpq.Queue('queue_name',host='localhost',dbname='foobar')q.put('{"foo": "bar"}')# Or use shortcut functions:tpq.put('queue_name','{"foo": "bar"}',host='localhost',dbname='foobar')tpq.get('queue_name',host='localhost',dbname='foobar')# Or to take advantage of cooperative transactions, provide a connection:q=tpq.Queue('queue_name',conn=connection)q.put('{"foo": "bar"}')# Which is also supported by shortcut functions:tpq.put('queue_name','{"foo": "bar"}',conn=connection)tpq.get('queue_name',conn=connection)

或者，您可以在环境中设置连接信息：

$ # Export as URL
$ export TPQ_URL="postgresql://user:pass@localhost/foobar"

$ # Or separately
$ export TPQ_HOST=localhost
$ export TPQ_DB=foobar
$ export TPQ_USER=user
$ export TPQ_PASS=pass

然后省略参数：

importtpq# Use an instance for multiple operationswithtpq.Queue('queue_name')asq:q.put('{"foo": "bar"}')data=q.get()# Or use shortcut functions:tpq.put('queue_name','{"foo": "bar"}')tpq.get('queue_name')

等待

您可以使用wait参数等待项目到达。

importtpq# Wait forevertpq.get('queue_name',wait=0)# Don't wait (also can omit the param).tpq.get('queue_name',wait=-1)# Wait specified number of seconds.tpq.get('queue_name',wait=5)

命令行界面

还提供了命令行界面。json可以通过文件或 stdin（默认值）。

$ # Configure your database.
$ export TPQ_URL="postgresql://user:pass@localhost/foobar"

$ # JSON via stdin (default).
$ echo "{\"foo\": \"bar\"}" | tpq produce queue_name

$ # JSON via file.
$ tpq produce queue_name --file=message.json

$ # Explicitly provide JSON via stdin.
$ tpq produce queue_name --file=- < message.json

$ # Then read the item to stdout.
$ tpq consume queue_name
{'foo': 'bar'}

$ # If you have trouble (or for logging). Debug output goes to stderr.
$ TPQ_URL="postgresql://user:pass@localhost/foobar" tpq consume queue_name --debug
Read database config from environment
Parsing TPQ_URL
Database config found
Attempting to read item
Item read, returning
{'foo': 'bar'}

$ # You can wait on the CLI too...
$ # Forever:
$ tpq consume queue_name --wait=0

$ # Specified number of seconds:
$ tpq consume queue_name --wait=5

$ # The return code signals whether an item was received or not.
$ tpq consume queue_name --wait=-1
{'foo': 'bar'}
$ echo $?
0

# For an empty queue, you get 1
$ tpq consume queue_name --wait=-1
Queue empty
Traceback (most recent call last):
  File "/home/btimby/Code/tpq/tpq/__main__.py", line 24, in consume
    print(get(opt['<name>'], wait=opt['--wait']))
  File "/home/btimby/Code/tpq/tpq/__init__.py", line 266, in get
    return q.get(wait=wait)
  File "/home/btimby/Code/tpq/tpq/__init__.py", line 233, in get
    raise QueueEmpty()
queue.Empty
$ echo $?
1