feat(http): Replace second layer of http cache with setting cache headers

plugin/http.go

@@ -23,11 +23,7 @@ type HTTP struct {
 	url, method string
 	headers     map[string]string
 	body        string
-	cache       time.Duration
-	updated     time.Time
 	pipeline    *pipeline.Pipeline
-	val         []byte // Cached http response value
-	err         error  // Cached http response error
 }
 
 func init() {
@@ -99,7 +95,6 @@ func NewHTTP(log *util.Logger, method, uri string, insecure bool, cache time.Dur
 		Helper: request.NewHelper(log),
 		url:    uri,
 		method: method,
-		cache:  cache,
 	}
 
 	// http cache
@@ -108,6 +103,16 @@ func NewHTTP(log *util.Logger, method, uri string, insecure bool, cache time.Dur
 		Transport: p.Client.Transport,
 	}
 
+	if cache > 0 {
+		cacheHeader := fmt.Sprintf("max-age=%d, must-revalidate", int(cache.Seconds()))
+		p.Client.Transport = &transport.Decorator{
+			Decorator: transport.DecorateHeaders(map[string]string{
+				"Cache-Control": cacheHeader,
+			}),
+			Base: p.Client.Transport,
+		}
+	}
+
 	// ignore the self signed certificate
 	if insecure {
 		p.Client.Transport = request.NewTripper(log, transport.Insecure())
@@ -152,30 +157,27 @@ func (p *HTTP) WithAuth(typ, user, password string) (*HTTP, error) {
 
 // request executes the configured request or returns the cached value
 func (p *HTTP) request(url string, body string) ([]byte, error) {
-	if time.Since(p.updated) >= p.cache {
-		var b io.Reader
-		if p.method != http.MethodGet {
-			b = strings.NewReader(body)
-		}
+	var b io.Reader
+	if p.method != http.MethodGet {
+		b = strings.NewReader(body)
+	}
 
-		url := util.DefaultScheme(url, "http")
+	url = util.DefaultScheme(url, "http")
 
-		// empty method becomes GET
-		req, err := request.New(p.method, url, b, p.headers)
-		if err != nil {
-			return []byte{}, err
-		}
+	// empty method becomes GET
+	req, err := request.New(p.method, url, b, p.headers)
+	if err != nil {
+		return []byte{}, err
+	}
 
-		p.val, p.err = p.DoBody(req)
-		if p.err != nil {
-			if err := knownErrors(p.val); err != nil {
-				p.err = err
-			}
+	val, err := p.DoBody(req)
+	if err != nil {
+		if err2 := knownErrors(val); err2 != nil {
+			err = err2
 		}
-		p.updated = time.Now()
 	}
 
-	return p.val, p.err
+	return val, err
 }
 
 var _ Getters = (*HTTP)(nil)

templates/definition/meter/enphase.yaml

@@ -29,6 +29,7 @@ render: |
       password: {{ .token }}
     insecure: true
     {{- end }}
+    cache: 5s
     jq: .consumption[] | select(.measurementType == "net-consumption").wNow
   currents:
     - source: http
@@ -39,6 +40,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .consumption[] | select(.measurementType == "net-consumption").activeCount >= 1 ) and ( .consumption[] | select(.measurementType == "net-consumption").lines | length >= 1 )) then .consumption[] | select(.measurementType == "net-consumption").lines[0].rmsCurrent else 0 end
     - source: http
       uri: http://{{ .host }}/production.json?details=1
@@ -48,6 +50,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .consumption[] | select(.measurementType == "net-consumption").activeCount >= 1 ) and ( .consumption[] | select(.measurementType == "net-consumption").lines | length >= 2 )) then .consumption[] | select(.measurementType == "net-consumption").lines[1].rmsCurrent else 0 end
     - source: http
       uri: http://{{ .host }}/production.json?details=1
@@ -57,6 +60,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .consumption[] | select(.measurementType == "net-consumption").activeCount >= 1 ) and ( .consumption[] | select(.measurementType == "net-consumption").lines | length >= 3 )) then .consumption[] | select(.measurementType == "net-consumption").lines[2].rmsCurrent else 0 end
   {{- end }}
   {{- if eq .usage "pv" }}
@@ -69,6 +73,7 @@ render: |
       password: {{ .token }}
     insecure: true
     {{- end }}
+    cache: 5s
     jq: if (.production | length) > 1 and (.production[] | select(.measurementType == "production").activeCount >= 1) then .production[] | select(.measurementType == "production").wNow else .production[] | select(.type == "inverters").wNow end
   energy:
     source: http
@@ -79,6 +84,7 @@ render: |
       password: {{ .token }}
     insecure: true
     {{- end }}
+    cache: 5s
     jq: if (.production | length) > 1 and (.production[] | select(.measurementType == "production").activeCount >= 1) then .production[] | select(.measurementType == "production").whLifetime else .production[] | select(.type == "inverters").whLifetime end
     scale: 0.001
   currents:
@@ -90,6 +96,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .production[] | select(.measurementType == "production").activeCount >= 1 ) and ( .production[] | select(.measurementType == "production").lines | length >= 1 )) then .production[] | select(.measurementType == "production").lines[0].rmsCurrent else 0 end
     - source: http
       uri: http://{{ .host }}/production.json?details=1
@@ -99,6 +106,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .production[] | select(.measurementType == "production").activeCount >= 1 ) and ( .production[] | select(.measurementType == "production").lines | length >= 2 )) then .production[] | select(.measurementType == "production").lines[1].rmsCurrent else 0 end
     - source: http
       uri: http://{{ .host }}/production.json?details=1
@@ -108,6 +116,7 @@ render: |
         password: {{ .token }}
       insecure: true
       {{- end }}
+      cache: 5s
       jq: if (( .production[] | select(.measurementType == "production").activeCount >= 1 ) and ( .production[] | select(.measurementType == "production").lines | length >= 3 )) then .production[] | select(.measurementType == "production").lines[2].rmsCurrent else 0 end
   {{- end }}
   {{- if eq .usage "battery" }}
@@ -120,6 +129,7 @@ render: |
       password: {{ .token }}
     insecure: true
     {{- end }}
+    cache: 5s
     jq: .storage[] | .wNow
   soc:
     source: http
@@ -130,6 +140,7 @@ render: |
       password: {{ .token }}
     insecure: true
     {{- end }}
+    cache: 5s
     jq: '[.[].devices[] | select(.percentFull != null) | .percentFull] | add / length'
   capacity: {{ .capacity }} # kWh
   {{- end }}