1 /* Blue Sky: File Systems in the Cloud
3 * Copyright (C) 2009 The Regents of the University of California
4 * Written by Michael Vrable <mvrable@cs.ucsd.edu>
13 #include "bluesky-private.h"
15 /* Interaction with cloud storage. We expose very simple GET/PUT style
16 * interface, which different backends can implement. Available backends
17 * (will) include Amazon S3 and a simple local store for testing purposes.
18 * Operations may be performed asynchronously. */
20 struct _BlueSkyStore {
21 const BlueSkyStoreImplementation *impl;
26 int pending; /* Count of operations not yet complete. */
29 GHashTable *store_implementations;
31 /* Thread pool for calling notifier functions when an operation completes.
32 * These are called in a separate thread for locking reasons: we want to call
33 * the notifiers without the lock on the async object held, but completion
34 * occurs when the lock is held--so we need some way to defer the call. This
35 * isn't really optimal from a cache-locality standpoint. */
36 static GThreadPool *notifier_thread_pool;
38 void bluesky_store_register(const BlueSkyStoreImplementation *impl,
41 g_hash_table_insert(store_implementations, g_strdup(name), (gpointer)impl);
44 BlueSkyStore *bluesky_store_new(const gchar *type)
46 const BlueSkyStoreImplementation *impl;
49 scheme = g_strdup(type);
50 path = strchr(scheme, ':');
56 impl = g_hash_table_lookup(store_implementations, scheme);
62 gpointer handle = impl->create(path);
68 BlueSkyStore *store = g_new(BlueSkyStore, 1);
70 store->handle = handle;
71 store->lock = g_mutex_new();
72 store->cond_idle = g_cond_new();
78 void bluesky_store_free(BlueSkyStore *store)
80 store->impl->destroy(store->handle);
84 BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
86 BlueSkyStoreAsync *async;
88 async = g_new(BlueSkyStoreAsync, 1);
90 async->lock = g_mutex_new();
91 async->completion_cond = g_cond_new();
93 async->status = ASYNC_NEW;
94 async->op = STORE_OP_NONE;
98 async->notifiers = NULL;
99 async->store_private = NULL;
104 gpointer bluesky_store_async_get_handle(BlueSkyStoreAsync *async)
106 return async->store->handle;
109 void bluesky_store_async_ref(BlueSkyStoreAsync *async)
114 g_return_if_fail(g_atomic_int_get(&async->refcount) > 0);
116 g_atomic_int_inc(&async->refcount);
119 void bluesky_store_async_unref(BlueSkyStoreAsync *async)
124 if (g_atomic_int_dec_and_test(&async->refcount)) {
125 async->store->impl->cleanup(async->store->handle, async);
126 g_mutex_free(async->lock);
127 g_cond_free(async->completion_cond);
129 bluesky_string_unref(async->data);
134 /* Block until the given operation has completed. */
135 void bluesky_store_async_wait(BlueSkyStoreAsync *async)
137 g_return_if_fail(async != NULL);
138 g_mutex_lock(async->lock);
140 if (async->status == ASYNC_NEW) {
141 g_error("bluesky_store_async_wait on a new async object!\n");
142 g_mutex_unlock(async->lock);
146 while (async->status != ASYNC_COMPLETE) {
147 g_cond_wait(async->completion_cond, async->lock);
150 g_mutex_unlock(async->lock);
153 /* Add a notifier function to be called when the operation completes. */
154 void bluesky_store_async_add_notifier(BlueSkyStoreAsync *async,
155 GFunc func, gpointer user_data)
157 struct BlueSkyNotifierList *nl = g_new(struct BlueSkyNotifierList, 1);
158 nl->next = async->notifiers;
160 nl->async = async; bluesky_store_async_ref(async);
161 nl->user_data = user_data;
162 if (async->status == ASYNC_COMPLETE) {
163 g_thread_pool_push(notifier_thread_pool, nl, NULL);
165 async->notifiers = nl;
169 /* Mark an asynchronous operation as complete. This should only be called by
170 * the store implementations. The lock should be held when calling this
171 * function. Any notifier functions will be called, but in a separate thread
172 * and without the lock held. */
173 void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async)
175 g_return_if_fail(async->status != ASYNC_COMPLETE);
177 bluesky_time_hires elapsed = bluesky_now_hires() - async->start_time;
179 g_mutex_lock(async->store->lock);
180 async->store->pending--;
181 if (async->store->pending == 0)
182 g_cond_broadcast(async->store->cond_idle);
183 g_mutex_unlock(async->store->lock);
185 async->status = ASYNC_COMPLETE;
186 g_cond_broadcast(async->completion_cond);
188 while (async->notifiers != NULL) {
189 struct BlueSkyNotifierList *nl = async->notifiers;
190 async->notifiers = nl->next;
191 g_thread_pool_push(notifier_thread_pool, nl, NULL);
194 g_log("bluesky/store", G_LOG_LEVEL_DEBUG,
195 "[%p] complete: elapsed = %"PRIi64" ns",
199 void bluesky_store_async_submit(BlueSkyStoreAsync *async)
201 BlueSkyStore *store = async->store;
203 async->start_time = bluesky_now_hires();
205 g_log("bluesky/store", G_LOG_LEVEL_DEBUG, "[%p] submit: %s %s",
207 async->op == STORE_OP_GET ? "GET"
208 : async->op == STORE_OP_PUT ? "PUT"
209 : async->op == STORE_OP_DELETE ? "DELETE"
210 : async->op == STORE_OP_BARRIER ? "BARRIER" : "???",
213 /* Barriers are handled specially, and not handed down the storage
214 * implementation layer. */
215 if (async->op == STORE_OP_BARRIER) {
216 async->status = ASYNC_RUNNING;
217 if (GPOINTER_TO_INT(async->store_private) == 0)
218 bluesky_store_async_mark_complete(async);
222 g_mutex_lock(async->store->lock);
223 async->store->pending++;
224 g_mutex_unlock(async->store->lock);
226 store->impl->submit(store->handle, async);
228 if (bluesky_options.synchronous_stores)
229 bluesky_store_async_wait(async);
232 static void op_complete(gpointer a, gpointer b)
234 BlueSkyStoreAsync *barrier = (BlueSkyStoreAsync *)b;
236 bluesky_store_async_ref(barrier);
237 g_mutex_lock(barrier->lock);
238 barrier->store_private
239 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) - 1);
240 if (GPOINTER_TO_INT(barrier->store_private) == 0
241 && barrier->status != ASYNC_NEW) {
242 bluesky_store_async_mark_complete(barrier);
244 g_mutex_unlock(barrier->lock);
245 bluesky_store_async_unref(barrier);
248 /* Add the given operation to the barrier. The barrier will not complete until
249 * all operations added to it have completed. */
250 void bluesky_store_add_barrier(BlueSkyStoreAsync *barrier,
251 BlueSkyStoreAsync *async)
253 g_return_if_fail(barrier->op == STORE_OP_BARRIER);
254 barrier->store_private
255 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) + 1);
256 bluesky_store_async_add_notifier(async, op_complete, barrier);
259 static void notifier_task(gpointer n, gpointer s)
261 struct BlueSkyNotifierList *notifier = (struct BlueSkyNotifierList *)n;
263 notifier->func(notifier->async, notifier->user_data);
264 bluesky_store_async_unref(notifier->async);
268 void bluesky_store_sync(BlueSkyStore *store)
270 g_mutex_lock(store->lock);
271 g_print("Waiting for pending store operations to complete...\n");
272 while (store->pending > 0) {
273 g_cond_wait(store->cond_idle, store->lock);
275 g_mutex_unlock(store->lock);
276 g_print("Operations are complete.\n");
279 /* Convenience wrappers that perform a single operation synchronously. */
280 BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
282 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
283 async->op = STORE_OP_GET;
284 async->key = g_strdup(key);
285 bluesky_store_async_submit(async);
287 bluesky_store_async_wait(async);
289 BlueSkyRCStr *data = async->data;
290 bluesky_string_ref(data);
291 bluesky_store_async_unref(async);
295 void bluesky_store_put(BlueSkyStore *store,
296 const gchar *key, BlueSkyRCStr *val)
298 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
299 async->op = STORE_OP_PUT;
300 async->key = g_strdup(key);
301 bluesky_string_ref(val);
303 bluesky_store_async_submit(async);
305 bluesky_store_async_wait(async);
306 bluesky_store_async_unref(async);
309 /* Simple in-memory data store for test purposes. */
313 /* TODO: A hashtable isn't optimal for list queries... */
317 static gpointer memstore_create(const gchar *path)
319 MemStore *store = g_new(MemStore, 1);
320 store->lock = g_mutex_new();
321 store->store = g_hash_table_new_full(g_str_hash, g_str_equal,
323 (GDestroyNotify)bluesky_string_unref);
325 return (gpointer)store;
328 static void memstore_destroy(gpointer store)
333 static BlueSkyRCStr *memstore_get(gpointer st, const gchar *key)
335 MemStore *store = (MemStore *)st;
336 BlueSkyRCStr *s = g_hash_table_lookup(store->store, key);
338 bluesky_string_ref(s);
342 static void memstore_put(gpointer s, const gchar *key, BlueSkyRCStr *val)
344 MemStore *store = (MemStore *)s;
345 bluesky_string_ref(val);
346 g_hash_table_insert(store->store, g_strdup(key), val);
349 static void memstore_submit(gpointer s, BlueSkyStoreAsync *async)
351 g_return_if_fail(async->status == ASYNC_NEW);
352 g_return_if_fail(async->op != STORE_OP_NONE);
356 async->data = memstore_get(s, async->key);
360 memstore_put(s, async->key, async->data);
364 g_warning("Uknown operation type for MemStore: %d\n", async->op);
368 bluesky_store_async_mark_complete(async);
371 static void memstore_cleanup(gpointer store, BlueSkyStoreAsync *async)
375 static BlueSkyStoreImplementation memstore_impl = {
376 .create = memstore_create,
377 .destroy = memstore_destroy,
378 .submit = memstore_submit,
379 .cleanup = memstore_cleanup,
382 /* Store implementation which writes data as files to disk. */
383 static gpointer filestore_create(const gchar *path)
385 return GINT_TO_POINTER(1);
388 static void filestore_destroy()
392 static BlueSkyRCStr *filestore_get(const gchar *key)
394 gchar *contents = NULL;
396 GError *error = NULL;
398 g_file_get_contents(key, &contents, &length, &error);
399 if (contents == NULL)
402 return bluesky_string_new(contents, length);
405 static void filestore_put(const gchar *key, BlueSkyRCStr *val)
407 g_file_set_contents(key, val->data, val->len, NULL);
410 static void filestore_submit(gpointer s, BlueSkyStoreAsync *async)
412 g_return_if_fail(async->status == ASYNC_NEW);
413 g_return_if_fail(async->op != STORE_OP_NONE);
417 async->data = filestore_get(async->key);
422 filestore_put(async->key, async->data);
427 g_warning("Uknown operation type for FileStore: %d\n", async->op);
431 bluesky_store_async_mark_complete(async);
434 static void filestore_cleanup(gpointer store, BlueSkyStoreAsync *async)
438 static BlueSkyStoreImplementation filestore_impl = {
439 .create = filestore_create,
440 .destroy = filestore_destroy,
441 .submit = filestore_submit,
442 .cleanup = filestore_cleanup,
445 void bluesky_store_init()
447 store_implementations = g_hash_table_new(g_str_hash, g_str_equal);
448 notifier_thread_pool = g_thread_pool_new(notifier_task, NULL, -1, FALSE,
450 bluesky_store_register(&memstore_impl, "mem");
451 bluesky_store_register(&filestore_impl, "file");