/
query.go
183 lines (170 loc) · 4.18 KB
/
query.go
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
package evhttp
import (
"context"
"encoding/json"
"io/ioutil"
"mime"
"net/http"
"net/url"
"strings"
"time"
"github.com/alxarch/evdb"
"github.com/alxarch/evdb/evql"
"github.com/alxarch/evdb/evutil"
"github.com/alxarch/httperr"
errors "golang.org/x/xerrors"
)
// Querier runs queries over http
type Querier struct {
URL string
HTTPClient
}
// Query implements evdb.Evaler interface
func (qr *Querier) Query(ctx context.Context, r evdb.TimeRange, q string) ([]interface{}, error) {
body := strings.NewReader(q)
u, err := TimeRangeURL(qr.URL, &r)
if err != nil {
return nil, err
}
req, err := http.NewRequest(http.MethodPost, u, body)
if err != nil {
return nil, err
}
var results []interface{}
if err := sendJSON(ctx, qr.HTTPClient, req, &results); err != nil {
return nil, err
}
return results, nil
}
// QueryHandler returns an HTTP endpoint for a QueryRunner
func QueryHandler(scanner evdb.Scanner) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
var q query
switch r.Method {
case http.MethodGet:
values := r.URL.Query()
q.Query = values.Get("query")
q.Format = values.Get("format")
t, err := TimeRangeFromURL(values)
if err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
q.TimeRange = t
case http.MethodPost:
defer r.Body.Close()
data, err := ioutil.ReadAll(r.Body)
if err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
m, _, _ := mime.ParseMediaType(r.Header.Get("Content-Type"))
switch m {
case "application/x-www-form-urlencoded":
values, err := url.ParseQuery(string(data))
if err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
t, err := TimeRangeFromURL(values)
if err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
q.TimeRange = t
q.Query = values.Get("query")
q.Format = values.Get("format")
case "application/json":
if err := json.Unmarshal(data, &q); err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
default:
err := errors.Errorf("Invalid MIME type: %q", m)
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
default:
httperr.RespondJSON(w, httperr.MethodNotAllowed(nil))
return
}
if q.Step < time.Second {
err := errors.New("Invalid query.step")
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
now := time.Now()
if q.End.IsZero() || q.End.After(now) {
q.End = now
}
if q.Start.IsZero() || q.Start.After(q.End) {
q.Start = q.End.Add(-1 * q.Step)
}
e, err := evql.Parse(q.Query)
if err != nil {
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
queries := e.Queries(q.TimeRange)
if len(queries) == 0 {
err := errors.New("Empty query")
httperr.RespondJSON(w, httperr.BadRequest(err))
return
}
results, err := scanner.Scan(r.Context(), queries...)
if err != nil {
httperr.RespondJSON(w, errors.Errorf("Query evaluation failed: %s", err))
return
}
rows := e.Eval(nil, q.TimeRange, results)
if out, ok := evutil.FormatResults(q.Format, rows...); ok {
httperr.RespondJSON(w, out)
return
}
err = errors.Errorf("Invalid query format: %q", q.Format)
httperr.RespondJSON(w, httperr.BadRequest(err))
}
}
type query struct {
Query string
evdb.TimeRange
Format string
}
type jsonQuery struct {
Query string `json:"query"`
Format string `json:"format,omitempty"`
Start string `json:"start"`
End string `json:"end"`
Step string `json:"step"`
}
func (q *query) MarshalJSON() ([]byte, error) {
tmp := jsonQuery{
Start: q.Start.Format(time.RFC3339Nano),
End: q.End.Format(time.RFC3339Nano),
Step: q.Step.String(),
Query: q.Query,
}
return json.Marshal(&tmp)
}
func (q *query) UnmarshalJSON(data []byte) error {
var tmp jsonQuery
if err := json.Unmarshal(data, &tmp); err != nil {
return err
}
q.Query = tmp.Query
q.Format = tmp.Format
start, err := ParseTime(tmp.Start)
if err != nil {
return err
}
end, err := ParseTime(tmp.End)
if err != nil {
return err
}
step, err := time.ParseDuration(tmp.Step)
if err != nil {
return err
}
q.Start, q.End, q.Step = start, end, step
return nil
}