Support specifying additional values either hardcoded or pulling from…

… an env var

README.md

@@ -21,6 +21,22 @@ steps:
 The host where this agent can reach a running instance of dogstatsd for
 reporting metrics to.
 
+### `dogstatsd_port` (Optional, string)
+
+The port where this agent can reach dogstatsd on wherever is specified
+in `dogstatsd_host`. This defaults to the default port for dogstatsd
+which is `8125`.
+
+### `additional_tags` (Optional, array)
+
+This is an array of additional tags you want to send and where to find
+them in the environment variables. Each entry is an object with
+properties
+
+* `tag` which is the tag name to send to datadog
+* `env_var` which is the environment variable to pull the tag's value from
+* `value` which is a static value to send for that tag
+
 ## Developing
 
 To run the tests:

lib/get-tags.sh

@@ -1,3 +1,29 @@
+#!/bin/bash
+
+function readAdditionalTags() {
+  local result=()
+  # Provide a limit to avoid accidental infinite loops
+  for i in {0..100}; do
+    tag_var="BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_${i}_TAG"
+    env_var="BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_${i}_ENV_VAR"
+    value_var="BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_${i}_VALUE"
+
+    if [[ -z ${!tag_var:-} ]]; then
+      break;
+    fi
+
+    if [ -z ${!env_var:-} ]; then
+      # If env_var is not set, then a hard-coded value must be
+      result+=("${!tag_var}:${!value_var}")
+    else
+      local env_var_value=${!env_var}
+      result+=("${!tag_var}:${!env_var_value:-}")
+    fi
+  done
+
+  echo -n "$(IFS=$','; echo "${result[*]}" | sed 's/,$//')"
+}
+
 function getTags() {
   BK_COMMAND=${BUILDKITE_COMMAND}
   BK_LABEL=${BUILDKITE_LABEL}
@@ -10,6 +36,13 @@ function getTags() {
 
   PIPELINE_SLUG=${BUILDKITE_PIPELINE_SLUG}
   RETRY_COUNT=${BUILDKITE_RETRY_COUNT:-0}
+  ADDITIONAL_TAGS=$(readAdditionalTags)
+
+  RESULT="is_master:${IS_MASTER},pipeline_slug:${PIPELINE_SLUG},step_command:${BK_COMMAND},step_label:${BK_LABEL},retry_count:${RETRY_COUNT}"
+
+  if [ -n "ADDITIONAL_TAGS" ]; then
+    RESULT+=",${ADDITIONAL_TAGS}"
+  fi
 
-  echo is_master:${IS_MASTER},pipeline_slug:${PIPELINE_SLUG},step_command:${BK_COMMAND},step_label:${BK_LABEL},retry_count:${RETRY_COUNT}
+  echo "${RESULT}"
 }

plugin.yml

@@ -10,6 +10,18 @@ configuration:
       type: string
     dogstatsd_port:
       type: string
+    additional_tags:
+      type: array
+      minimum: 1
+      items:
+        type: object
+        properties:
+          tag:
+            type: string
+          env_var:
+            type: string
+          value:
+            type: string
   required:
     - dogstatsd_host
   additionalProperties: false

tests/post-commands.bats

@@ -43,3 +43,34 @@ load "$BATS_PATH/load.bash"
   unset BUILDKITE_COMMAND
   unset BUILDKITE_LABEL
 }
+
+@test "It supports specifying additional tags by value and env var" {
+  NOW=$(date +%s%3N)
+  export BUILDKITE_PLUGIN_DATADOG_STATS_COMMAND_START_TIME_MS=$(($NOW-900))
+  export BUILDKITE_BRANCH=some-branch
+  export BUILDKITE_PIPELINE_SLUG=monorepo
+  export BUILDKITE_COMMAND="cd somewhere && make do-something"
+  export BUILDKITE_LABEL=":shipit: deploy-prod"
+  export BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_TAG="my-tag"
+  export BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_ENV_VAR="MY_ENV_VAR"
+  export MY_ENV_VAR="my-tag-value"
+  export BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_1_TAG="my-other-tag"
+  export BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_1_VALUE="my-other-tag-value"
+
+  run "$PWD/hooks/post-command"
+
+  assert_success
+  assert_output --partial "Reporting buildkite.steps.duration as 90"
+  assert_output --partial "tags is_master:false,pipeline_slug:monorepo,step_command:cd somewhere && make do-something,step_label::shipit: deploy-prod,retry_count:0,my-tag:my-tag-value,my-other-tag:my-other-tag-value"
+
+  unset BUILDKITE_PLUGIN_DATADOG_STATS_COMMAND_START_TIME_MS
+  unset BUILDKITE_BRANCH
+  unset BUILDKITE_PIPELINE_SLUG
+  unset BUILDKITE_COMMAND
+  unset BUILDKITE_LABEL
+  unset BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_TAG
+  unset BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_ENV_VAR
+  unset MY_ENV_VAR
+  unset BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_TAG
+  unset BUILDKITE_PLUGIN_DATADOG_STATS_ADDITIONAL_TAGS_0_VALUE
+}