Merge pull request #311 from square/nathan-fenner-uncapitalize-errors

lowercase error messages for better composability

demo/emit/mock.go

@@ -112,11 +112,11 @@ func reportMetric(client *http.Client, value float64, name string, options ...in
 
 	request, err := http.NewRequest("POST", *bluefloodAddress, bytes.NewBuffer([]byte(json)))
 	if err != nil {
-		return fmt.Errorf("Error creating Blueflood request: %s\n", err.Error())
+		return fmt.Errorf("error creating Blueflood request: %s\n", err.Error())
 	}
 	response, err := client.Do(request)
 	if err != nil {
-		return fmt.Errorf("Error performing Blueflood POST: %s\n", err.Error())
+		return fmt.Errorf("error performing Blueflood POST: %s\n", err.Error())
 	}
 	fmt.Println("Blueflood: ", response.Status)
 	body, _ := ioutil.ReadAll(response.Body)
@@ -126,11 +126,11 @@ func reportMetric(client *http.Client, value float64, name string, options ...in
 
 	request, err = http.NewRequest("POST", *mqeIngestionAddress, bytes.NewBuffer([]byte(metricName)))
 	if err != nil {
-		return fmt.Errorf("Error creating MQE Ingestion request: %s\n", err.Error())
+		return fmt.Errorf("error creating MQE Ingestion request: %s\n", err.Error())
 	}
 	response, err = client.Do(request)
 	if err != nil {
-		return fmt.Errorf("Error performing MQE Ingestion POST: %s\n", err.Error())
+		return fmt.Errorf("error performing MQE Ingestion POST: %s\n", err.Error())
 	}
 	fmt.Println("MQE: ", response.Status)
 	body, _ = ioutil.ReadAll(response.Body)

function/builtin/forecast/anomaly_function.go

@@ -118,7 +118,7 @@ func standardDeviationsFromExpected(correct []float64, estimate []float64) ([]fl
 }
 func periodicStandardDeviationsFromExpected(correct []float64, estimate []float64, period int) ([]float64, error) {
 	if period <= 0 {
-		return nil, fmt.Errorf("Period must be strictly positive")
+		return nil, fmt.Errorf("period must be strictly positive")
 	}
 	if len(correct) != len(estimate) {
 		return nil, fmt.Errorf("to estimate anomaly values, the ground truth and estimate slices must be the same length")

function/builtin/forecast/rolling_function.go

@@ -35,7 +35,7 @@ var FunctionRollingMultiplicativeHoltWinters = function.MakeFunction(
 			extraTrainingTime = *optionalExtraTrainingTime
 		}
 		if extraTrainingTime < 0 {
-			return api.SeriesList{}, fmt.Errorf("Extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
+			return api.SeriesList{}, fmt.Errorf("extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
 		}
 
 		samples := int(period / context.Timerange().Resolution())
@@ -76,7 +76,7 @@ var FunctionRollingSeasonal = function.MakeFunction(
 			extraTrainingTime = *optionalExtraTrainingTime
 		}
 		if extraTrainingTime < 0 {
-			return api.SeriesList{}, fmt.Errorf("Extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
+			return api.SeriesList{}, fmt.Errorf("extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
 		}
 
 		samples := int(period / context.Timerange().Resolution())
@@ -117,7 +117,7 @@ var FunctionLinear = function.MakeFunction(
 			extraTrainingTime = *optionalTrainingTime
 		}
 		if extraTrainingTime < 0 {
-			return api.SeriesList{}, fmt.Errorf("Extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
+			return api.SeriesList{}, fmt.Errorf("extra training time must be non-negative, but got %s", extraTrainingTime.String()) // TODO: use structured error
 		}
 
 		newContext := context.WithTimerange(context.Timerange().ExtendBefore(extraTrainingTime))

function/builtin/forecast/utility.go

@@ -16,11 +16,6 @@ package forecast
 
 import "math"
 
-// Returns the unique integer r such that x == r (mod m) and 0 <= r < m
-func mod(x int, m int) int {
-	return ((x % m) + m) % m
-}
-
 // LinearRegression estimates ys as (a + b*t) and returns (a, b).
 // It performs linear regression using the explicit form for minimization of least-squares error.
 // When ys[i] is NaN, it is treated as a missing point. (This makes things only slightly more complicated).

function/registry/registry_test.go

@@ -23,7 +23,7 @@ import (
 )
 
 var dummyCompute = func(function.EvaluationContext, []function.Expression, function.Groups) (function.Value, error) {
-	return nil, errors.New("Not implemented")
+	return nil, errors.New("not implemented")
 }
 
 func Test_Registry_Default(t *testing.T) {

main/ruletester/ruletester.go

@@ -48,7 +48,7 @@ func ReadMetricsFile(file string) ([]string, error) {
 	r, err := zlib.NewReader(bytes.NewBuffer(data))
 	defer r.Close()
 	if err != nil {
-		return nil, fmt.Errorf("Problem with zlib compressed data: %s", err.Error())
+		return nil, fmt.Errorf("problem with zlib compressed data: %s", err.Error())
 	}
 
 	// Store the result of the decode in this map:

metric_metadata/cached/cached.go

@@ -181,7 +181,7 @@ func (c *metricMetadataAPI) CheckHealthy() error {
 // item in the cache.
 func (c *metricMetadataAPI) fetchAndUpdateCachedTagSet(item *TagSetList, metricKey api.MetricKey, context metadata.Context) ([]api.TagSet, error) {
 	if item == nil {
-		return nil, errors.New("Missing cache list entry")
+		return nil, errors.New("missing cache list entry")
 	}
 
 	item.wg.Add(1)

query/command/command.go

@@ -329,7 +329,7 @@ func (cmd *SelectCommand) Execute(context ExecutionContext) (Result, error) {
 				}
 				continue
 			}
-			return Result{}, fmt.Errorf("Query %s does not result in a timeseries or scalar.", cmd.Expressions[i].ExpressionString(function.StringQuery))
+			return Result{}, fmt.Errorf("query %s does not result in a timeseries or scalar.", cmd.Expressions[i].ExpressionString(function.StringQuery))
 		}
 
 		return Result{

query/expression/expression.go

@@ -184,7 +184,8 @@ type AnnotationExpression struct {
 	Annotation string
 }
 
-// AnnotationExpression implements Evaluate rather than ActualEvaluate so that it doesn't cause memoization.
+// Evaluate evalutes the underlying expression without memoization, since its
+// child expression should handle memoization itself.
 func (expr *AnnotationExpression) Evaluate(context function.EvaluationContext) (function.Value, error) {
 	return expr.Expression.Evaluate(context)
 }

testing_support/mocks/api.go

@@ -107,13 +107,13 @@ func (fa *FakeGraphiteConverter) ToGraphiteName(metric api.TaggedMetric) (util.G
 			return k, nil
 		}
 	}
-	return "", fmt.Errorf("No mapping for tagged metric %+v to tagged metric", metric)
+	return "", fmt.Errorf("no mapping for tagged metric %+v to tagged metric", metric)
 }
 
 func (fa *FakeGraphiteConverter) ToTaggedName(metric util.GraphiteMetric) (api.TaggedMetric, error) {
 	tm, exists := fa.MetricMap[metric]
 	if !exists {
-		return api.TaggedMetric{}, fmt.Errorf("No mapping for graphite metric %+s to graphite metric", string(metric))
+		return api.TaggedMetric{}, fmt.Errorf("no mapping for graphite metric %+s to graphite metric", string(metric))
 	}
 
 	return tm, nil

testing_support/mocks/combo_api.go

@@ -73,7 +73,7 @@ var _ metadata.MetricAPI = FakeComboAPI{}
 
 func (fapi FakeComboAPI) ChooseResolution(requested api.Timerange, smallestResolution time.Duration) (time.Duration, error) {
 	if requested.Resolution() != fapi.timerange.Resolution() {
-		return 0, fmt.Errorf("FakeComboAPI has internal resolution %+v but user requested %+v", fapi.timerange.Resolution(), requested.Resolution())
+		return 0, fmt.Errorf("the FakeComboAPI has internal resolution %+v but user requested %+v", fapi.timerange.Resolution(), requested.Resolution())
 	}
 	return requested.Resolution(), nil
 }

testing_support/mocks/http_client.go

@@ -46,7 +46,7 @@ func (c *FakeHTTPClient) SetResponse(url string, r Response) {
 func (c *FakeHTTPClient) Get(url string) (*http.Response, error) {
 	r, exists := c.responses[url]
 	if !exists {
-		return nil, fmt.Errorf("Get() received unexpected url %s, mappings: %+v", url, c.responses)
+		return nil, fmt.Errorf("the FakeHTTPClient's Get() method received unexpected url %s, mappings: %+v", url, c.responses)
 	}
 
 	if r.Delay > 0 {

timeseries/blueflood/blueflood.go

@@ -107,7 +107,7 @@ func (b *Blueflood) CheckHealthy() error {
 		if err != nil {
 			return err
 		}
-		return fmt.Errorf("Blueflood returned an unhealthy status of %d: %s", resp.StatusCode, string(body))
+		return fmt.Errorf("the Blueflood instance returned an unhealthy status of %d: %s", resp.StatusCode, string(body))
 	}
 
 	return nil

timeseries/blueflood/plan_intervals.go

@@ -72,7 +72,7 @@ func planFetchIntervalsWithOnlyFiner(resolutions []Resolution, now time.Time, re
 	for i := range resolutions {
 		if resolutions[i].Resolution > requestRange.Resolution() {
 			if i == 0 {
-				return nil, fmt.Errorf("No resolutions are available at least as fine as the chosen %+v", requestRange.Resolution())
+				return nil, fmt.Errorf("no resolutions are available at least as fine as the chosen %+v", requestRange.Resolution())
 			}
 			return planFetchIntervals(resolutions[:i], now, requestRange.Interval())
 		}