store: Added sdb_store_fetch_timeseries().

The function fetches a time-series for a specified host's metric and
serializes it into a JSON buffer.

diff --git a/src/core/store.c b/src/core/store.c
index 2565eca4c27feadab488efecec8e2921c7bfd434..c778c52d7dd4a234890b381bea8fb5434a4bab0a 100644 (file)
--- a/src/core/store.c
+++ b/src/core/store.c
@@ -441,6 +441,7 @@ store_common_tojson(sdb_store_obj_t *obj, sdb_strbuf_t *buf)
        char interval_str[64];
        size_t i;
 
+       /* TODO: make time and interval formats configurable */
        if (! sdb_strftime(time_str, sizeof(time_str),
                                "%F %T %z", obj->last_update))
                snprintf(time_str, sizeof(time_str), "<error>");
@@ -530,6 +531,60 @@ store_obj_tojson(sdb_avltree_t *tree, int type, sdb_strbuf_t *buf,
        sdb_strbuf_append(buf, "]");
 } /* store_obj_tojson */
 
+/*
+ * ts_tojson serializes a time-series to JSON.
+ *
+ * The function never returns an error. Rather, an error message will be part
+ * of the serialized data.
+ */
+static void
+ts_tojson(sdb_timeseries_t *ts, sdb_strbuf_t *buf)
+{
+       char start_str[64];
+       char end_str[64];
+
+       size_t i;
+
+       /* TODO: make time format configurable */
+       if (! sdb_strftime(start_str, sizeof(start_str),
+                               "%F %T %z", ts->start))
+               snprintf(start_str, sizeof(start_str), "<error>");
+       start_str[sizeof(start_str) - 1] = '\0';
+       if (! sdb_strftime(end_str, sizeof(end_str),
+                               "%F %T %z", ts->start))
+               snprintf(end_str, sizeof(end_str), "<error>");
+       end_str[sizeof(end_str) - 1] = '\0';
+
+       sdb_strbuf_append(buf, "{\"start\": \"%s\", \"end\": \"%s\", {",
+                       start_str, end_str);
+
+       for (i = 0; i < ts->data_names_len; ++i) {
+               size_t j;
+               sdb_strbuf_append(buf, "\"%s\": [", ts->data_names[i]);
+
+               for (j = 0; j < ts->data_len; ++j) {
+                       char time_str[64];
+
+                       if (! sdb_strftime(time_str, sizeof(time_str),
+                                               "%F %T %z", ts->data[i][j].timestamp))
+                               snprintf(time_str, sizeof(time_str), "<error>");
+                       time_str[sizeof(time_str) - 1] = '\0';
+
+                       sdb_strbuf_append(buf, "{\"timestamp\": \"%s\", "
+                                       "\"value\": \"%s\"}", time_str, ts->data[i][j].value);
+
+                       if (j < ts->data_len - 1)
+                               sdb_strbuf_append(buf, ",");
+               }
+
+               if (i < ts->data_names_len - 1)
+                       sdb_strbuf_append(buf, "],");
+               else
+                       sdb_strbuf_append(buf, "]");
+       }
+       sdb_strbuf_append(buf, "}}");
+} /* ts_tojson */
+
 /*
  * public API
  */
@@ -756,7 +811,7 @@ sdb_store_metric_attr(const char *hostname, const char *metric,
        metrics = get_host_children(hostname, SDB_METRIC);
        if (! metrics) {
                sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' "
-                               "for metric '%s' - host '%ss' not found",
+                               "for metric '%s' - host '%s' not found",
                                key, metric, hostname);
                pthread_rwlock_unlock(&host_lock);
                return -1;
@@ -777,6 +832,65 @@ sdb_store_metric_attr(const char *hostname, const char *metric,
        return status;
 } /* sdb_store_metric_attr */
 
+int
+sdb_store_fetch_timeseries(const char *hostname, const char *metric,
+               sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf)
+{
+       sdb_avltree_t *metrics;
+       sdb_metric_t *m;
+
+       sdb_timeseries_t *ts;
+
+       if ((! hostname) || (! metric) || (! opts) || (! buf))
+               return -1;
+
+       pthread_rwlock_rdlock(&host_lock);
+       metrics = get_host_children(hostname, SDB_METRIC);
+       if (! metrics) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
+                               "- host '%s' not found", hostname, metric, hostname);
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
+
+       m = METRIC(sdb_avltree_lookup(metrics, metric));
+       if (! m) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
+                               "- metric '%s' not found", hostname, metric, metric);
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
+
+       if ((! m->store.type) || (! m->store.id)) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
+                               "- no data-store configured for the stored metric",
+                               hostname, metric);
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
+
+       {
+               char type[strlen(m->store.type) + 1];
+               char id[strlen(m->store.id) + 1];
+
+               strncpy(type, m->store.type, sizeof(type));
+               strncpy(id, m->store.id, sizeof(id));
+               pthread_rwlock_unlock(&host_lock);
+
+               ts = sdb_plugin_fetch_timeseries(type, id, opts);
+               if (! ts) {
+                       sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
+                                       "- %s fetcher callback returned no data for '%s'",
+                                       hostname, metric, type, id);
+                       return -1;
+               }
+       }
+
+       ts_tojson(ts, buf);
+       sdb_timeseries_destroy(ts);
+       return 0;
+} /* sdb_store_fetch_timeseries */
+
 int
 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res)
 {

diff --git a/src/include/core/store.h b/src/include/core/store.h
index 2d3d707161e73e851e68bcd5bbcc722f0b3d9a46..7c94a974297d46cb4107df7ea8773e036343a8d8 100644 (file)
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
@@ -32,6 +32,7 @@
 #include "core/object.h"
 #include "core/data.h"
 #include "core/time.h"
+#include "core/timeseries.h"
 #include "utils/strbuf.h"
 
 #include <stdio.h>
@@ -221,6 +222,19 @@ int
 sdb_store_metric_attr(const char *hostname, const char *metric,
                const char *key, const sdb_data_t *value, sdb_time_t last_update);
 
+/*
+ * sdb_store_fetch_timeseries:
+ * Fetch the time-series described by the specified host's metric and
+ * serialize it as JSON into the provided string buffer.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - a negative value else
+ */
+int
+sdb_store_fetch_timeseries(const char *hostname, const char *metric,
+               sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
+
 /*
  * sdb_store_get_field:
  * Get the value of a stored object's queryable field. The caller is