feat: add new emit-metrics action

.github/actions/emit-metrics/action.yml

@@ -0,0 +1,74 @@
+name: Emit Metrics
+description: Emit metrics from another workflow/action using the kat tool
+inputs:
+  namespace:
+    description: The CloudWatch namespace in which to emit metrics
+    required: true
+  dimensions:
+    description: |-
+      The dimensions to include with emitted metrics, as a collection of `name=value` pairs. Multiple dimensions are
+      delimited by newlines (`\n`) and whitespace is trimmed from before/after each `name=value` pair. When passing
+      multiple dimensions, make sure to use YAML's block literal syntax (`|` or `|-`).
+
+      For example:
+      ```
+      dimensions: |
+        Artifact=foo-artifact
+        Platform=Kotlin/JVM
+        Variant=External
+      ```
+    required: true
+  metrics:
+    description: |-
+      The metrics to emit into the given namespace and using the specified dimensions. Individual metrics are written in
+      the form of `<name>:<value>[:<unit>]` where:
+      * <name> is the metric name and may include spaces but not colons (`:`)
+      * <value> is the numeric value of the metric
+      * <unit> is the CloudWatch unit name (if omitted, `None` is assumed)
+
+      Multiple metrics are delimited by newlines (`\n`) and whitespace is trimmed from before/after each metric
+      specification. When passing multiple metrics, make sure to use YAML's block literal syntax (`|` or `|-`).
+
+      For example:
+      ```
+      metrics: |
+        BuildTime:4.532:Seconds
+        BuildSucceeded:1:Count
+      ```
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Emit Metrics
+      shell: bash
+      run: |
+        # Trim a string and echo the result
+        trim() {
+          # args:
+          #   $1 the string to trim
+
+          echo -n "$1" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//'
+        }
+
+        # Convert a newline-delimited string into a single-line string delimited by spaces with each element prefixed
+        format() {
+          # args:
+          #   $1 the prefix for each element
+          #   $2 the newline-delimited string
+
+          PROCESSED=""
+          IFS=$'\n'; ARR=($2); unset IFS
+          for ITEM in "${ARR[@]}"; do
+            PROCESSED="$PROCESSED $1 \"$(trim "$ITEM")\""
+          done
+          echo -n "$(trim "$PROCESSED")"
+        }
+
+        NAMESPACE="--namespace \"${{ inputs.namespace }}\""
+        DIMENSIONS="$(format "--dimension" "${{ inputs.dimensions }}")"
+        METRICS="$(format "--metric" "${{ inputs.metrics }}")"
+        CMD="kat metrics emit $NAMESPACE $DIMENSIONS $METRICS"
+
+        echo "Executing command \"$CMD\""
+        eval "$CMD"

.github/workflows/test-emit-metrics.yml

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+name: Test the emit-metrics action
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - feat-emit-metrics-action
+
+permissions:
+  id-token: write
+
+jobs:
+  emit-a-metric:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Configure AWS Credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          role-to-assume: ${{ secrets.TEST_CI_AWS_ROLE_ARN }}
+          aws-region: us-west-2
+      - name: Set up kat tool
+        uses: ./.github/actions/setup-kat
+      - name: Emit some test metrics
+        uses: ./.github/actions/emit-metrics
+        with:
+          namespace: Test Namespace (ignore me)
+          dimensions: |
+            Artifact=foo-artifact
+            Platform=Kotlin/JVM
+            Variant=External
+          metrics: |
+            BuildTime:4.532:Seconds
+            BuildSucceeded:1:Count