1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
#!/usr/bin/python3
import asyncio
import asyncpg
import json
import logging
class JobQueue(object):
def __init__(self):
self._pool = None
async def connect(self, **args):
"""Connect the database."""
logging.info("connecting to queue database")
while True:
try:
self._pool = await asyncpg.create_pool(
min_size=1, **args)
break
except asyncpg.exceptions.CannotConnectNowError:
logging.warning(
"queue database is not ready yet, retrying")
await asyncio.sleep(1)
except asyncpg.exceptions.TooManyConnectionsError:
logging.warning(
"queue database has too many clients, retrying")
await asyncio.sleep(1)
async def setup(self):
"""Initialize the database."""
async with self._pool.acquire() as con:
await con.execute("""
CREATE TABLE IF NOT EXISTS
jobs (
id SERIAL PRIMARY KEY,
priority INT DEFAULT 0,
status TEXT DEFAULT 'open',
type TEXT,
payload JSONB
)
""")
await con.execute("""
CREATE UNIQUE INDEX ON jobs(priority, id)
""")
async def request(self, jobtype, payload, priority=0):
"""Create a new job and return its id."""
async with self._pool.acquire() as con:
insert = await con.prepare("""
INSERT INTO jobs(type, payload, priority)
VALUES($1, $2, $3)
RETURNING id
""")
if isinstance(payload, list):
payloads = payload
else:
payloads = [payload]
if isinstance(priority, list):
priorities = priority
else:
priorities = [priority] * len(payloads)
ids = []
async with con.transaction():
for pl, pr in zip(payloads, priorities):
ids.append(await insert.fetchval(jobtype,
json.dumps(pl),
pr))
if isinstance(payload, list):
return ids
else:
return ids[0]
async def acquire(self, jobtype, length=None):
"""Mark a job as running, return id, payload and priority.
Return (None, None, None) if no job is available."""
async with self._pool.acquire() as con:
update = await con.prepare("""
UPDATE jobs SET STATUS='running'
FROM (
SELECT id FROM jobs
WHERE status='open' AND type=$1
ORDER BY priority, id
LIMIT $2
) AS open_jobs
WHERE jobs.id=open_jobs.id
RETURNING jobs.id, jobs.payload, jobs.priority
""")
if length is None:
limit = 1
else:
limit = length
while True:
try:
# do not allow async access
async with con.transaction(isolation="serializable"):
result = await update.fetch(jobtype, limit)
if len(result) == 0 and length is None:
# no jobs available
# backwards compatibility
return None, None, None
jobs = []
for record in result:
jobs.append((record[0],
json.loads(record[1]),
record[2]))
if length is None:
return jobs[0]
else:
return jobs
except asyncpg.exceptions.SerializationError:
# job is being picked up by another worker, try again
logging.debug("serialization error, retrying")
pass
async def status(self, jobid):
"""Return the status of a job."""
async with self._pool.acquire() as con:
return await con.fetchval("""
SELECT status
FROM jobs WHERE
id=$1
""", jobid)
async def finish(self, jobid):
"""Mark jobs as completed."""
async with self._pool.acquire() as con:
update = await con.prepare("""
UPDATE jobs
SET status='finished'
WHERE id=$1
""")
if not isinstance(jobid, list):
jobids = [jobid]
else:
jobids = jobid
async with con.transaction():
for jid in jobids:
await update.fetch(jid)
async def fail(self, jobid, reason):
"""Mark a job as failed."""
async with self._pool.acquire() as con:
update = await con.prepare("""
UPDATE jobs
SET status='failed', payload=payload||$2::jsonb
WHERE id=$1
""")
if not isinstance(jobid, list):
jobids = [jobid]
else:
jobids = jobid
if not isinstance(reason, list):
reasons = [reason]
else:
reasons = reason
assert len(jobids) == len(reasons)
async with con.transaction():
for jid, rsn in zip(jobids, reasons):
await update.fetch(jid,
json.dumps({"error": rsn}))
async def reset(self, jobid):
"""Mark a job as open."""
async with self._pool.acquire() as con:
update = await con.prepare("""
UPDATE jobs
SET status='open'
WHERE id=$1
""")
if not isinstance(jobid, list):
jobids = [jobid]
else:
jobids = jobid
async with con.transaction():
for jid in jobids:
await update.fetch(jid)
async def cleanup(self):
"""Reopen all unfinished jobs."""
async with self._pool.acquire() as con:
while True:
try:
async with con.transaction(isolation="serializable"):
await con.execute("""
UPDATE jobs
SET status='open'
WHERE status='running'
""")
return
except asyncpg.exceptions.SerializationError:
pass
|
