![[tokkee]](http://tokkee.org/images/avatar.png){kind=avatar}
diff --git a/sysdb/store.go b/sysdb/store.go
--- /dev/null
+++ b/sysdb/store.go
@@ -0,0 +1,249 @@
+//
+// Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+// 1. Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package sysdb
+
+import (
+ "fmt"
+ "time"
+)
+
+// The SysDB JSON time format.
+const jsonTime = `"2006-01-02 15:04:05 -0700"`
+
+// A Duration represents the elapsed time between two instants as a
+// nanoseconds count.
+//
+// It supports marshaling to and unmarshaling from the SysDB JSON format (a
+// sequence of decimal numbers with a unit suffix).
+type Duration time.Duration
+
+const (
+ Second = Duration(1000000000)
+ Minute = 60 * Second
+ Hour = 60 * Minute
+ Day = 24 * Hour
+ Month = Duration(30436875 * 24 * 60 * 60 * 1000)
+ Year = Duration(3652425 * 24 * 60 * 60 * 100000)
+)
+
+// MarshalJSON implements the json.Marshaler interface. The time is a quoted
+// string in the SysDB JSON format.
+func (d Duration) MarshalJSON() ([]byte, error) {
+ if d == 0 {
+ return []byte(`"0s"`), nil
+ }
+
+ s := `"`
+ secs := false
+ for _, spec := range []struct {
+ interval Duration
+ suffix string
+ }{{Year, "Y"}, {Month, "M"}, {Day, "D"}, {Hour, "h"}, {Minute, "m"}, {Second, ""}} {
+ if d >= spec.interval {
+ s += fmt.Sprintf("%d%s", d/spec.interval, spec.suffix)
+ d %= spec.interval
+ if spec.interval == Second {
+ secs = true
+ }
+ }
+ }
+
+ if d > 0 {
+ s += fmt.Sprintf(".%09d", d)
+ for i := len(s) - 1; i > 0; i-- {
+ if s[i] != '0' {
+ break
+ }
+ s = s[:i]
+ }
+ secs = true
+ }
+ if secs {
+ s += "s"
+ }
+ s += `"`
+ return []byte(s), nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface. The duration is
+// expected to be a quoted string in the SysDB JSON format.
+func (d *Duration) UnmarshalJSON(data []byte) error {
+ m := map[string]Duration{
+ "Y": Year,
+ "M": Month,
+ "D": Day,
+ "h": Hour,
+ "m": Minute,
+ "s": Second,
+ }
+
+ if data[0] != '"' || data[len(data)-1] != '"' {
+ return fmt.Errorf("unquoted duration %q", string(data))
+ }
+ data = data[1 : len(data)-1]
+
+ orig := string(data)
+ var res Duration
+ for len(data) != 0 {
+ // consume digits
+ n := 0
+ dec := 0
+ frac := false
+ for n < len(data) && '0' <= data[n] && data[n] <= '9' {
+ dec = dec*10 + int(data[n]-'0')
+ n++
+ }
+ if n < len(data) && data[n] == '.' {
+ frac = true
+ n++
+
+ // consume fraction
+ m := 1000000000
+ for n < len(data) && '0' <= data[n] && data[n] <= '9' {
+ if m > 1 { // cut of to nanoseconds
+ dec = dec*10 + int(data[n]-'0')
+ m /= 10
+ }
+ n++
+ }
+ dec *= m
+ }
+ if n >= len(data) {
+ return fmt.Errorf("missing unit in duration %q", orig)
+ }
+ if n == 0 {
+ // we found something which is not a number
+ return fmt.Errorf("invalid duration %q", orig)
+ }
+
+ // consume unit
+ u := n
+ for u < len(data) && data[u] != '.' && (data[u] < '0' || '9' < data[u]) {
+ u++
+ }
+
+ unit := string(data[n:u])
+ data = data[u:]
+
+ // convert to Duration
+ d, ok := m[unit]
+ if !ok {
+ return fmt.Errorf("invalid unit %q in duration %q", unit, orig)
+ }
+
+ if d == Second {
+ if frac {
+ d = 1
+ }
+ } else if frac {
+ return fmt.Errorf("invalid fraction %q%s in duration %q", dec, unit, orig)
+ }
+
+ res += Duration(dec) * d
+ }
+ *d = res
+ return nil
+}
+
+// String returns the duration formatted using a predefined format string.
+func (d Duration) String() string { return time.Duration(d).String() }
+
+// A Time represents an instant in time with nanosecond precision.
+//
+// It supports marshaling to and unmarshaling from the SysDB JSON format
+// (YYYY-MM-DD hh:mm:ss +-zzzz).
+type Time time.Time
+
+func (t Time) MarshalJSON() ([]byte, error) {
+ return []byte(time.Time(t).Format(jsonTime)), nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface. The time is
+// expected to be a quoted string in the SysDB JSON format.
+func (t *Time) UnmarshalJSON(data []byte) error {
+ parsed, err := time.Parse(jsonTime, string(data))
+ if err == nil {
+ *t = Time(parsed)
+ }
+ return err
+}
+
+// Equal reports whether t and u represent the same time instant.
+func (t Time) Equal(u Time) bool {
+ return time.Time(t).Equal(time.Time(u))
+}
+
+// String returns the time formatted using a predefined format string.
+func (t Time) String() string { return time.Time(t).String() }
+
+// An Attribute describes a host, metric, or service attribute.
+type Attribute struct {
+ Name string `json:"name"`
+ Value string `json:"value"`
+ LastUpdate Time `json:"last_update"`
+ UpdateInterval Duration `json:"update_interval"`
+}
+
+// A Metric describes a metric known to SysDB.
+type Metric struct {
+ Name string `json:"name"`
+ LastUpdate Time `json:"last_update"`
+ UpdateInterval Duration `json:"update_interval"`
+ Attributes []Attribute `json:"attributes"`
+}
+
+// A Service describes a service object stored in the SysDB store.
+type Service struct {
+ Name string `json:"name"`
+ LastUpdate Time `json:"last_update"`
+ UpdateInterval Duration `json:"update_interval"`
+ Attributes []Attribute `json:"attributes"`
+}
+
+// A Host describes a host object stored in the SysDB store.
+type Host struct {
+ Name string `json:"name"`
+ LastUpdate Time `json:"last_update"`
+ UpdateInterval Duration `json:"update_interval"`
+ Attributes []Attribute `json:"attributes"`
+ Metrics []Metric `json:"metrics"`
+ Services []Service `json:"services"`
+}
+
+// A DataPoint describes a datum at a certain point of time.
+type DataPoint struct {
+ Timestamp Time `json:"timestamp"`
+ Value float64 `json:"value"`
+}
+
+// A Timeseries describes a sequence of data-points.
+type Timeseries struct {
+ Start Time `json:"start"`
+ End Time `json:"end"`
+ Data map[string][]DataPoint
+}
+
+// vim: set tw=78 sw=4 sw=4 noexpandtab :