root / Ganeti / Luxi.hs @ 8ed71b67
History | View | Annotate | Download (6.1 kB)
1 |
{-| Implementation of the Ganeti LUXI interface. |
---|---|
2 |
|
3 |
-} |
4 |
|
5 |
{- |
6 |
|
7 |
Copyright (C) 2009 Google Inc. |
8 |
|
9 |
This program is free software; you can redistribute it and/or modify |
10 |
it under the terms of the GNU General Public License as published by |
11 |
the Free Software Foundation; either version 2 of the License, or |
12 |
(at your option) any later version. |
13 |
|
14 |
This program is distributed in the hope that it will be useful, but |
15 |
WITHOUT ANY WARRANTY; without even the implied warranty of |
16 |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
17 |
General Public License for more details. |
18 |
|
19 |
You should have received a copy of the GNU General Public License |
20 |
along with this program; if not, write to the Free Software |
21 |
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
22 |
02110-1301, USA. |
23 |
|
24 |
-} |
25 |
|
26 |
module Ganeti.Luxi |
27 |
( LuxiOp(..) |
28 |
, Client |
29 |
, getClient |
30 |
, closeClient |
31 |
, callMethod |
32 |
, submitManyJobs |
33 |
, queryJobsStatus |
34 |
) where |
35 |
|
36 |
import Data.List |
37 |
import Data.IORef |
38 |
import Control.Monad |
39 |
import Text.JSON (JSObject, JSValue, toJSObject, encodeStrict, decodeStrict) |
40 |
import qualified Text.JSON as J |
41 |
import Text.JSON.Types |
42 |
import System.Timeout |
43 |
import qualified Network.Socket as S |
44 |
|
45 |
import Ganeti.HTools.Utils |
46 |
import Ganeti.HTools.Types |
47 |
|
48 |
import Ganeti.Jobs (JobStatus) |
49 |
|
50 |
-- * Utility functions |
51 |
|
52 |
-- | Wrapper over System.Timeout.timeout that fails in the IO monad. |
53 |
withTimeout :: Int -> String -> IO a -> IO a |
54 |
withTimeout secs descr action = do |
55 |
result <- timeout (secs * 1000000) action |
56 |
(case result of |
57 |
Nothing -> fail $ "Timeout in " ++ descr |
58 |
Just v -> return v) |
59 |
|
60 |
-- * Generic protocol functionality |
61 |
|
62 |
-- | Currently supported Luxi operations. |
63 |
data LuxiOp = QueryInstances |
64 |
| QueryNodes |
65 |
| QueryJobs |
66 |
| SubmitManyJobs |
67 |
|
68 |
-- | The serialisation of LuxiOps into strings in messages. |
69 |
strOfOp :: LuxiOp -> String |
70 |
strOfOp QueryNodes = "QueryNodes" |
71 |
strOfOp QueryInstances = "QueryInstances" |
72 |
strOfOp QueryJobs = "QueryJobs" |
73 |
strOfOp SubmitManyJobs = "SubmitManyJobs" |
74 |
|
75 |
-- | The end-of-message separator. |
76 |
eOM :: Char |
77 |
eOM = '\3' |
78 |
|
79 |
-- | Valid keys in the requests and responses. |
80 |
data MsgKeys = Method |
81 |
| Args |
82 |
| Success |
83 |
| Result |
84 |
|
85 |
-- | The serialisation of MsgKeys into strings in messages. |
86 |
strOfKey :: MsgKeys -> String |
87 |
strOfKey Method = "method" |
88 |
strOfKey Args = "args" |
89 |
strOfKey Success = "success" |
90 |
strOfKey Result = "result" |
91 |
|
92 |
-- | Luxi client encapsulation. |
93 |
data Client = Client { socket :: S.Socket -- ^ The socket of the client |
94 |
, rbuf :: IORef String -- ^ Already received buffer |
95 |
} |
96 |
|
97 |
-- | Connects to the master daemon and returns a luxi Client. |
98 |
getClient :: String -> IO Client |
99 |
getClient path = do |
100 |
s <- S.socket S.AF_UNIX S.Stream S.defaultProtocol |
101 |
withTimeout connTimeout "creating luxi connection" $ |
102 |
S.connect s (S.SockAddrUnix path) |
103 |
rf <- newIORef "" |
104 |
return Client { socket=s, rbuf=rf} |
105 |
|
106 |
-- | Closes the client socket. |
107 |
closeClient :: Client -> IO () |
108 |
closeClient = S.sClose . socket |
109 |
|
110 |
-- | Sends a message over a luxi transport. |
111 |
sendMsg :: Client -> String -> IO () |
112 |
sendMsg s buf = |
113 |
let _send obuf = do |
114 |
sbytes <- withTimeout queryTimeout |
115 |
"sending luxi message" $ |
116 |
S.send (socket s) obuf |
117 |
unless (sbytes == length obuf) $ _send (drop sbytes obuf) |
118 |
in _send (buf ++ [eOM]) |
119 |
|
120 |
-- | Waits for a message over a luxi transport. |
121 |
recvMsg :: Client -> IO String |
122 |
recvMsg s = do |
123 |
let _recv obuf = do |
124 |
nbuf <- withTimeout queryTimeout "reading luxi response" $ |
125 |
S.recv (socket s) 4096 |
126 |
let (msg, remaining) = break ((==) eOM) (obuf ++ nbuf) |
127 |
(if null remaining |
128 |
then _recv msg |
129 |
else return (msg, tail remaining)) |
130 |
cbuf <- readIORef $ rbuf s |
131 |
(msg, nbuf) <- _recv cbuf |
132 |
writeIORef (rbuf s) nbuf |
133 |
return msg |
134 |
|
135 |
-- | Serialize a request to String. |
136 |
buildCall :: LuxiOp -- ^ The method |
137 |
-> JSValue -- ^ The arguments |
138 |
-> String -- ^ The serialized form |
139 |
buildCall msg args = |
140 |
let ja = [(strOfKey Method, |
141 |
JSString $ toJSString $ strOfOp msg::JSValue), |
142 |
(strOfKey Args, |
143 |
args::JSValue) |
144 |
] |
145 |
jo = toJSObject ja |
146 |
in encodeStrict jo |
147 |
|
148 |
-- | Check that luxi responses contain the required keys and that the |
149 |
-- call was successful. |
150 |
validateResult :: String -> Result JSValue |
151 |
validateResult s = do |
152 |
arr <- fromJResult $ decodeStrict s::Result (JSObject JSValue) |
153 |
status <- fromObj (strOfKey Success) arr::Result Bool |
154 |
let rkey = strOfKey Result |
155 |
(if status |
156 |
then fromObj rkey arr |
157 |
else fromObj rkey arr >>= fail) |
158 |
|
159 |
-- | Generic luxi method call. |
160 |
callMethod :: LuxiOp -> JSValue -> Client -> IO (Result JSValue) |
161 |
callMethod method args s = do |
162 |
sendMsg s $ buildCall method args |
163 |
result <- recvMsg s |
164 |
let rval = validateResult result |
165 |
return rval |
166 |
|
167 |
-- | Specialized submitManyJobs call. |
168 |
submitManyJobs :: Client -> JSValue -> IO (Result [String]) |
169 |
submitManyJobs s jobs = do |
170 |
rval <- callMethod SubmitManyJobs jobs s |
171 |
-- map each result (status, payload) pair into a nice Result ADT |
172 |
return $ case rval of |
173 |
Bad x -> Bad x |
174 |
Ok (JSArray r) -> |
175 |
mapM (\v -> case v of |
176 |
JSArray [JSBool True, JSString x] -> |
177 |
Ok (fromJSString x) |
178 |
JSArray [JSBool False, JSString x] -> |
179 |
Bad (fromJSString x) |
180 |
_ -> Bad "Unknown result from the master daemon" |
181 |
) r |
182 |
x -> Bad ("Cannot parse response from Ganeti: " ++ show x) |
183 |
|
184 |
-- | Custom queryJobs call. |
185 |
queryJobsStatus :: Client -> [String] -> IO (Result [JobStatus]) |
186 |
queryJobsStatus s jids = do |
187 |
rval <- callMethod QueryJobs (J.showJSON (jids, ["status"])) s |
188 |
return $ case rval of |
189 |
Bad x -> Bad x |
190 |
Ok y -> case J.readJSON y::(J.Result [[JobStatus]]) of |
191 |
J.Ok vals -> if any null vals |
192 |
then Bad "Missing job status field" |
193 |
else Ok (map head vals) |
194 |
J.Error x -> Bad x |