Add depends_on field for core service ordering

* Adds depends_on fields to compose YAML
* Updates parsing code to copy across depends_on field to
openfaas service from compose service definition
* Adds algorithm and unit tests for finding order
* Applies order to up.go command
* Makes unit testing on MacOS possible through build directives

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/testdata/docker-compose.yaml

@@ -1,12 +1,12 @@
 version: "3.7"
 services:
   basic-auth-plugin:
-    image: docker.io/openfaas/basic-auth-plugin:0.18.17
+    image: "docker.io/openfaas/basic-auth-plugin:0.18.17${ARCH_SUFFIX}"
     environment:
-      port: "8080"
-      secret_mount_path: "/run/secrets"
-      user_filename: "basic-auth-user"
-      pass_filename: "basic-auth-password"
+      - port=8080
+      - secret_mount_path=/run/secrets
+      - user_filename=basic-auth-user
+      - pass_filename=basic-auth-password
     volumes:
       # we assume cwd == /var/lib/faasd
       - type: bind
@@ -17,6 +17,7 @@ services:
         target: /run/secrets/basic-auth-user
     cap_add:
       - CAP_NET_RAW
+
   nats:
     image: docker.io/library/nats-streaming:0.11.2
     command:
@@ -25,6 +26,7 @@ services:
       - "8222"
       - "--store=memory"
       - "--cluster_id=faas-cluster"
+
   prometheus:
     image: docker.io/prom/prometheus:v2.14.0
     volumes:
@@ -33,21 +35,22 @@ services:
         target: /etc/prometheus/prometheus.yml
     cap_add:
       - CAP_NET_RAW
+
   gateway:
-    image: docker.io/openfaas/gateway:0.18.17
+    image: "docker.io/openfaas/gateway:0.18.17${ARCH_SUFFIX}"
     environment:
-      basic_auth: "true"
-      functions_provider_url: "http://faasd-provider:8081/"
-      direct_functions: "false"
-      read_timeout: "60s"
-      write_timeout: "60s"
-      upstream_timeout: "65s"
-      faas_nats_address: "nats"
-      faas_nats_port: "4222"
-      auth_proxy_url: "http://basic-auth-plugin:8080/validate"
-      auth_proxy_pass_body: "false"
-      secret_mount_path: "/run/secrets"
-      scale_from_zero: "true"
+      - basic_auth=true
+      - functions_provider_url=http://faasd-provider:8081/
+      - direct_functions=false
+      - read_timeout=60s
+      - write_timeout=60s
+      - upstream_timeout=65s
+      - faas_nats_address=nats
+      - faas_nats_port=4222
+      - auth_proxy_url=http://basic-auth-plugin:8080/validate
+      - auth_proxy_pass_body=false
+      - secret_mount_path=/run/secrets
+      - scale_from_zero=true
     volumes:
       # we assume cwd == /var/lib/faasd
       - type: bind
@@ -58,18 +61,23 @@ services:
         target: /run/secrets/basic-auth-user
     cap_add:
       - CAP_NET_RAW
+    depends_on:
+      - basic-auth-plugin
+      - nats
+      - prometheus
+
   queue-worker:
     image: docker.io/openfaas/queue-worker:0.11.2
     environment:
-      faas_nats_address: "nats"
-      faas_nats_port: "4222"
-      gateway_invoke: "true"
-      faas_gateway_address: "gateway"
-      ack_wait: "5m5s"
-      max_inflight: "1"
-      write_debug: "false"
-      basic_auth: "true"
-      secret_mount_path: "/run/secrets"
+      - faas_nats_address=nats
+      - faas_nats_port=4222
+      - gateway_invoke=true
+      - faas_gateway_address=gateway
+      - ack_wait=5m5s
+      - max_inflight=1
+      - write_debug=false
+      - basic_auth=true
+      - secret_mount_path=/run/secrets
     volumes:
       # we assume cwd == /var/lib/faasd
       - type: bind
@@ -80,3 +88,5 @@ services:
         target: /run/secrets/basic-auth-user
     cap_add:
       - CAP_NET_RAW
+    depends_on:
+      - nats