Fix Docker health check requests for GLV integration tests

The health checks in the GLV docker-compose files were sending malformed
HTTP requests to Gremlin Server which lacked the Content-Type header.
This caused the server to mishandle the requests leading to "Connection
reset by peer" errors that could interfere with concurrent test
execution, producing intermittent NullPointerException failures in
random integration tests.

Installed curl in the test server Docker image at build time so that
health checks no longer need to run "apk add curl" on every invocation.
Updated all four GLV docker-compose health checks (dotnet, go,
javascript, python) to send properly formed JSON requests with the
correct Content-Type header. Also fixed the Python health check which
had an unquoted JSON body and an invalid traversal source reference. CTR

Author: spmallette

docker/gremlin-test-server/Dockerfile

@@ -29,7 +29,7 @@ RUN chmod 755 /opt/docker-entrypoint.sh
 
 # Installing dos2unix to avoid errors in running the entrypoint script on Windows machines where their
 # carriage return is \r\n instead of the \n needed for linux/unix containers
-RUN apk update && apk add dos2unix
+RUN apk update && apk add dos2unix curl
 RUN dos2unix /opt/docker-entrypoint.sh /opt/gremlin-server/bin/gremlin-server.sh && apk del dos2unix
 
 ARG GREMLIN_SERVER

gremlin-dotnet/docker-compose.yml

@@ -35,7 +35,7 @@ services:
       - ${HOME}/.m2:/root/.m2
       - ${ABS_PROJECT_HOME}/gremlin-test/target:/opt/gremlin-test
     healthcheck:
-      test: [ "CMD-SHELL", "apk add curl && curl -X POST -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
+      test: [ "CMD-SHELL", "curl -sf -X POST -H 'Content-Type: application/json' -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
       interval: 30s
       timeout: 10s
       retries: 30

gremlin-go/docker-compose.yml

@@ -35,7 +35,7 @@ services:
       - ${HOME}/.m2:/root/.m2
       - ${ABS_PROJECT_HOME}/gremlin-test/target:/opt/gremlin-test
     healthcheck:
-      test: [ "CMD-SHELL", "apk add curl && curl -X POST -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
+      test: [ "CMD-SHELL", "curl -sf -X POST -H 'Content-Type: application/json' -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
       interval: 30s
       timeout: 10s
       retries: 30

gremlin-js/gremlin-javascript/docker-compose.yml

@@ -35,7 +35,7 @@ services:
       - ${HOME}/.m2:/root/.m2
       - ${ABS_PROJECT_HOME}/gremlin-test/target:/opt/gremlin-test
     healthcheck:
-      test: [ "CMD-SHELL", "apk add curl && curl -X POST -d '{\"gremlin\":\"g.inject(0)\"}' http://localhost:45940" ]
+      test: [ "CMD-SHELL", "curl -sf -X POST -H 'Content-Type: application/json' -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
       interval: 30s
       timeout: 10s
       retries: 30

gremlin-python/docker-compose.yml

@@ -35,7 +35,7 @@ services:
       - ${HOME}/.m2:/root/.m2
       - ${ABS_PROJECT_HOME}/gremlin-test/target:/opt/gremlin-test
     healthcheck:
-      test: [ "CMD-SHELL", "apk add curl && curl -X POST -d {\"gremlin\":\"gremlin.inject(1)\"} http://localhost:45940" ]
+      test: [ "CMD-SHELL", "curl -sf -X POST -H 'Content-Type: application/json' -d '{\"gremlin\":\"g.inject(1)\"}' http://localhost:45940" ]
       interval: 30s
       timeout: 10s
       retries: 30