Add logrus for structured logging

This adds the logrus package to facilitate structured logging. Logrus is
encapsulated in the log/ subpackage and currently used in the influx/
subpackage.

Godeps

@@ -1,5 +1,6 @@
 github.com/PuerkitoBio/purell 8a290539e2e8629dbc4e6bad948158f790ec31f4
 github.com/PuerkitoBio/urlesc 5bd2802263f21d8788851d5305584c82a5c75d7e
+github.com/Sirupsen/logrus 3ec0642a7fb6488f65b06f9040adc67e3990296a
 github.com/asaskevich/govalidator 593d64559f7600f29581a3ee42177f5dbded27a9
 github.com/boltdb/bolt 5cc10bbbc5c141029940133bb33c9e969512a698
 github.com/elazarl/go-bindata-assetfs 9a6736ed45b44bf3835afeebb3034b57ed329f3e

influx/influx.go

@@ -7,6 +7,7 @@ import (
 	"net/url"
 
 	"github.com/influxdata/mrfusion"
+	"github.com/influxdata/mrfusion/log"
 
 	"golang.org/x/net/context"
 )
@@ -14,18 +15,23 @@ import (
 // Client is a device for retrieving time series data from an InfluxDB instance
 type Client struct {
 	URL *url.URL
+
+	lg log.Logger
 }
 
 // NewClient initializes an HTTP Client for InfluxDB. UDP, although supported
 // for querying InfluxDB, is not supported here to remove the need to
 // explicitly Close the client.
-func NewClient(host string) (*Client, error) {
+func NewClient(host string, lg log.Logger) (*Client, error) {
+	l := lg.WithField("host", host)
 	u, err := url.Parse(host)
 	if err != nil {
+		l.Error("Error initialize influx client: err:", err)
 		return nil, err
 	}
 	return &Client{
 		URL: u,
+		lg:  l,
 	}, nil
 }
 
@@ -38,7 +44,7 @@ func (r Response) MarshalJSON() ([]byte, error) {
 	return r.Results, nil
 }
 
-func query(u *url.URL, q mrfusion.Query) (mrfusion.Response, error) {
+func (c *Client) query(u *url.URL, q mrfusion.Query) (mrfusion.Response, error) {
 	u.Path = "query"
 
 	req, err := http.NewRequest("POST", u.String(), nil)
@@ -74,12 +80,19 @@ func query(u *url.URL, q mrfusion.Query) (mrfusion.Response, error) {
 
 	// If we got a valid decode error, send that back
 	if decErr != nil {
-		return nil, fmt.Errorf("unable to decode json: received status code %d err: %s", resp.StatusCode, decErr)
+		c.lg.
+			WithField("influx_status", resp.StatusCode).
+			Error("Error parsing results from influxdb: err:", decErr)
+		return nil, decErr
 	}
 
 	// If we don't have an error in our json response, and didn't get statusOK
 	// then send back an error
 	if resp.StatusCode != http.StatusOK && response.Err != "" {
+		c.lg.
+			WithField("influx_status", resp.StatusCode).
+			Error("Received non-200 response from influxdb")
+
 		return &response, fmt.Errorf("received status code %d from server",
 			resp.StatusCode)
 	}
@@ -98,7 +111,7 @@ type result struct {
 func (c *Client) Query(ctx context.Context, q mrfusion.Query) (mrfusion.Response, error) {
 	resps := make(chan (result))
 	go func() {
-		resp, err := query(c.URL, q)
+		resp, err := c.query(c.URL, q)
 		resps <- result{resp, err}
 	}()
 

influx/influx_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/influxdata/mrfusion"
 	"github.com/influxdata/mrfusion/influx"
+	"github.com/influxdata/mrfusion/log"
 	"golang.org/x/net/context"
 )
 
@@ -25,7 +26,7 @@ func Test_Influx_MakesRequestsToQueryEndpoint(t *testing.T) {
 	defer ts.Close()
 
 	var series mrfusion.TimeSeries
-	series, err := influx.NewClient(ts.URL)
+	series, err := influx.NewClient(ts.URL, log.New())
 	if err != nil {
 		t.Fatal("Unexpected error initializing client: err:", err)
 	}
@@ -58,7 +59,7 @@ func Test_Influx_CancelsInFlightRequests(t *testing.T) {
 		ts.Close()
 	}()
 
-	series, _ := influx.NewClient(ts.URL)
+	series, _ := influx.NewClient(ts.URL, log.New())
 	ctx, cancel := context.WithCancel(context.Background())
 
 	errs := make(chan (error))
@@ -99,3 +100,27 @@ func Test_Influx_CancelsInFlightRequests(t *testing.T) {
 		t.Error("Expected timeout error but wasn't. err was", err)
 	}
 }
+
+func Test_Influx_RejectsInvalidHosts(t *testing.T) {
+	_, err := influx.NewClient(":", log.New())
+	if err == nil {
+		t.Fatal("Expected err but was nil")
+	}
+}
+
+func Test_Influx_ReportsInfluxErrs(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		rw.WriteHeader(http.StatusOK)
+	}))
+	defer ts.Close()
+
+	cl, err := influx.NewClient(ts.URL, log.New())
+	if err != nil {
+		t.Fatal("Encountered unexpected error while initializing influx client: err:", err)
+	}
+
+	_, err = cl.Query(context.Background(), mrfusion.Query{"show shards", "_internal", "autogen"})
+	if err == nil {
+		t.Fatal("Expected an error but received none")
+	}
+}

log/log.go

@@ -0,0 +1,26 @@
+package log
+
+import (
+	"os"
+
+	"github.com/Sirupsen/logrus"
+)
+
+type Logger interface {
+	Info(...interface{})
+	Warn(...interface{})
+	Debug(...interface{})
+	Panic(...interface{})
+	Error(...interface{})
+
+	WithField(string, interface{}) *logrus.Entry
+}
+
+func New() Logger {
+	return &logrus.Logger{
+		Out:       os.Stderr,
+		Formatter: new(logrus.TextFormatter),
+		Hooks:     make(logrus.LevelHooks),
+		Level:     logrus.DebugLevel,
+	}
+}

restapi/configure_mr_fusion.go

@@ -17,6 +17,7 @@ import (
 	"github.com/influxdata/mrfusion/dist"
 	"github.com/influxdata/mrfusion/handlers"
 	"github.com/influxdata/mrfusion/influx"
+	fusionlog "github.com/influxdata/mrfusion/log"
 	"github.com/influxdata/mrfusion/mock"
 	op "github.com/influxdata/mrfusion/restapi/operations"
 )