Make binary statically compiled again (#27)

* Fixes #26 so the distroless container works again * Add smoke test for containers in CI pipeline
thought-machine · Jun 12, 2023 · d99aad7 · d99aad7
1 parent 6a60f55
commit d99aad7
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Showing 7 changed files with 34 additions and 46 deletions.
diff --git a/.circleci/config.yml b/.circleci/config.yml
@@ -10,21 +10,29 @@ jobs:
  - checkout
  - run:
  name: Build Alpine Docker Image
- command: docker build -f Dockerfile-builder . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"
+ command: |
+ docker build -f Dockerfile-builder . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"
+ docker run --rm -it thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1" --help
  - run:
  name: Build distroless Docker Image
- command: docker build -f Dockerfile-builder_distroless . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless
+ command: |
+ docker build -f Dockerfile-builder_distroless . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless
+ docker run --rm -it thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless --help
  build_and_release:
  working_directory: ~/prometheus-cardinality-exporter
  machine: true
  steps:
  - checkout
  - run:
  name: Build Alpine Docker Image
- command: docker build -f Dockerfile-builder . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"
+ command: |
+ docker build -f Dockerfile-builder . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"
+ docker run --rm -it thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1" --help
  - run:
  name: Build distroless Docker Image
- command: docker build -f Dockerfile-builder_distroless . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless
+ command: |
+ docker build -f Dockerfile-builder_distroless . --rm=false -t thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless
+ docker run --rm -it thoughtmachine/prometheus-cardinality-exporter:"$CIRCLE_SHA1"_distroless --help
  - run:
  name: Publish Docker Images to Docker Hub
  command: |

diff --git a/Dockerfile-builder b/Dockerfile-builder
@@ -5,20 +5,18 @@ RUN ln -s /usr/local/go/bin/go /usr/local/bin/go
 
 RUN apk add --no-cache curl wget gcc make bash git musl-dev libc6-compat gettext
 
-RUN touch /root/.profile
-
-
 WORKDIR /go/github.com/thought-machine/prometheus-cardinality-exporter
 
 COPY . .
 
-# So the binary is where we expect it
-RUN go build .
-
 RUN go build ./...
 
 RUN go test ./... -race
 
+# So the binary is where we expect it
+# env var and flags ensure a static binary
+RUN CGO_ENABLED=0 go build -ldflags="-extldflags=-static" .
+
 # alpine:3.18.0
 FROM alpine@sha256:c0669ef34cdc14332c0f1ab0c2c01acb91d96014b172f1a76f3a39e63d1f0bda
 

diff --git a/Dockerfile-builder_distroless b/Dockerfile-builder_distroless
@@ -5,19 +5,18 @@ RUN ln -s /usr/local/go/bin/go /usr/local/bin/go
 
 RUN apk add --no-cache curl wget gcc make bash git musl-dev libc6-compat gettext
 
-RUN touch /root/.profile
-
 WORKDIR /go/github.com/thought-machine/prometheus-cardinality-exporter
 
 COPY . .
 
-# So the binary is where we expect it
-RUN go build .
-
 RUN go build ./...
 
 RUN go test ./... -race
 
+# So the binary is where we expect it
+# env var and flags ensure a static binary
+RUN CGO_ENABLED=0 go build -ldflags="-extldflags=-static" .
+
 FROM scratch
 
 EXPOSE 9090

diff --git a/Dockerfile-prometheus-cardinality-exporter b/Dockerfile-prometheus-cardinality-exporter
diff --git a/Dockerfile-prometheus-cardinality-exporter_distroless b/Dockerfile-prometheus-cardinality-exporter_distroless
diff --git a/README.md b/README.md
@@ -21,7 +21,7 @@ There are 4 types of metric exposed:
 ```
 ## Options
 
-(```plz run //:prometheus-cardinality-exporter -- [OPTIONS]```)
+(```go run . [OPTIONS]```)
 
 | Short Flag | Long Flag | Description |
 |------------|---------------------|--------------------------------------------------------------------------------------|
@@ -73,8 +73,10 @@ See https://hub.docker.com/r/thoughtmachine/prometheus-cardinality-exporter
 ```go run . --port=<port-to-serve-on> --proms=<prometheus-instance-to-expose> [--proms=<prometheus-instance-to-expose>...] --freq=<frequency-to-ping-api>```
 
 ### Running Within a Kubernetes Cluster (with service discovery)
-#### In order to deploy to a kubernetes cluster, run:
-```plz run //k8s:k8s_push```
+#### In order to deploy to a kubernetes cluster:
+
+Tweak and apply the files in k8s/
+
 #### Make sure you alter the k8s/deployment.yaml such that it contains the options that you require:
 In the example below, all of the possible flags that can be used with the ```--service_discovery``` option are included.\
 NOTE: not all flags are required, for example, you do not need the ```--auth``` flag if none of your Prometheus instances require authorization to access.

diff --git a/main.go b/main.go
@@ -238,10 +238,17 @@ func collectMetrics() {
 }
 
 func main() {
- flags.Parse(&opts)
+ _, err := flags.Parse(&opts)
+
+ // Exit gracefully if help flag used
+ if err != nil && flags.WroteHelp(err) {
+ os.Exit(0)
+ } else if err != nil {
+ log.Fatalf("%+v", err)
+ }
 
  if len(opts.PrometheusInstances) > 0 && opts.ServiceDiscovery {
- log.Fatal("Cannot parse Prometheus Instances (--proms) AND use Service Discorvery (--service_discovery), these options are mutually exclusive.")
+ log.Fatal("Cannot parse Prometheus Instances (--proms) AND use Service Discovery (--service_discovery), these options are mutually exclusive.")
  } else if len(opts.PrometheusInstances) > 0 {
  log.Info("Obtaining metics from prometheus instances specified as arguments.")
  } else if opts.ServiceDiscovery {