Fix: Fix building of Postfix exporter with newer version of Go and other architectures

Build should be faster now as well, as it's being built on the build
platform and not through QEMU.

.github/actions/build-postfix-exporter/action.yaml

@@ -47,7 +47,7 @@ runs:
         context: postfix_exporter
         push: true
         tags: '${{ inputs.tags }}'
-        platforms: "linux/386,linux/arm/v5,linux/arm/v6,linux/arm/v7,linux/arm64/v8,linux/amd64,linux/arm64,linux/ppc64le,linux/s390x"
+        platforms: "linux/386,linux/arm/v5,linux/arm/v6,linux/arm/v7,linux/arm64/v8,linux/amd64,linux/arm64,linux/ppc64le,linux/s390x,linux/mips64le,linux/riscv64"
         cache-from: type=local,src=/tmp/.buildx-cache/postfix-exporter,mode=max,compression=estargz
         cache-to: type=local,dest=/tmp/.buildx-cache-new/postfix-exporter
 

.github/workflows/master.yml

@@ -94,7 +94,8 @@ jobs:
             boky/postfix:edge-alpine
           # linux/s390x: "rsyslog (no such package)"
           # Latest Alpine does not have all the packages for 386 anymore. :-(
-          platforms: "linux/arm/v6,linux/arm/v7,linux/amd64,linux/arm64,linux/ppc64le"
+          # Latest Alpine does not have 'pandoc' in 'linux/arm/v7', which means SASL module cannot be built
+          platforms: "linux/arm/v6,linux/amd64,linux/arm64,linux/ppc64le"
           cache-from: type=local,src=/tmp/.buildx-cache/alpine,mode=max,compression=estargz
           cache-to: type=local,dest=/tmp/.buildx-cache-new/alpine
           build-args: |

helm/mail/templates/statefulset.yaml

@@ -158,20 +158,13 @@ spec:
             - name: {{ $fullName | quote }}
               mountPath: {{ regexFind "^/?.*/" .Values.metrics.maillog | quote }}
               subPath: logs
-          startupProbe:
-            exec:
-              command:
-                - sh
-                - -c
-                - >-
-                  [ -f {{ .Values.metrics.maillog | quote }} ] && grep -qi "starting the Postfix mail system" {{ .Values.metrics.maillog | quote }}
-            failureThreshold: 30
-            periodSeconds: 10
           readinessProbe:
             httpGet:
               path: {{ .Values.metrics.path | quote }} 
               port: {{ .Values.metrics.port }}
             initialDelaySeconds: 5
+            failureThreshold: 30
+            periodSeconds: 10
         {{- end }}
         {{- if .Values.extraContainers }}
         {{- tpl .Values.extraContainers $root | nindent 8 }}

postfix-exporter-01.patch

@@ -1,12 +1,25 @@
 diff --git a/Dockerfile b/Dockerfile
-index a3327d8..ce8e22c 100644
+index a3327d8..c082f5b 100644
 --- a/Dockerfile
 +++ b/Dockerfile
-@@ -14,7 +14,15 @@ COPY . .
+@@ -1,4 +1,10 @@
+-FROM golang:1.16 AS builder
++# syntax=docker/dockerfile:1.2
++FROM --platform=$BUILDPLATFORM golang:1.21 AS builder
++ARG TARGETPLATFORM
++ARG TARGETOS
++ARG TARGETARCH
++ARG TARGETVARIANT
++
+ WORKDIR /src
+ 
+ # avoid downloading the dependencies on succesive builds
+@@ -14,10 +20,18 @@ COPY . .
  
  # Force the go compiler to use modules
  ENV GO111MODULE=on
 -RUN go test
+-RUN go build -o /bin/postfix_exporter
 +# go test fails (sometimes) because it relies on an external dependency:
 +#
 +# warning: SASL authentication failure: cannot connect to saslauthd server: Permission denied
@@ -16,6 +29,10 @@ index a3327d8..ce8e22c 100644
 +# Since we are checking out a specific SHA hash and we know this tests have worked previously, we are quite certain that the code will work.
 +# Hence disabling the test here.
 +# RUN go test
- RUN go build -o /bin/postfix_exporter
++RUN env GOOS=$TARGETOS GOARCH=$TARGETARCH GOARM=$TARGETVARIANT go build -ldflags '-extldflags "-static"'  -o /bin/postfix_exporter
  
- FROM debian:latest
+-FROM debian:latest
++FROM scratch
+ EXPOSE 9154
+ WORKDIR /
+ COPY --from=builder /bin/postfix_exporter /bin/