03_redispinger-service

Redis Pinger Service

This Redis Pinger Service is an HTTP service that allows clients to ping a Redis instance. It uses the pingredis package from the previous example in 02_ping-redis in its implementation.

This example looks more like a system/integration test: the test makes a real HTTP request to a real HTTP service.

Full mode

"Full" mode for this example is straightforward to run -- docket takes care of everything for you.

                                                pinger
                           tester            +-----------+          redis
                        +-----------+        |           |       +---------+
                        |           |        |  go run   |       |         |
go test +----------------> go test +----------> service ----------> redis  |
          (docker exec) |           | (HTTP) |           | (TCP) |         |
                        +-----------+        +-----------+       +---------+

Here's what running the test in "full" mode looks like:

$ DOCKET_MODE=full DOCKET_DOWN=1 go test
[docket] config [docker-compose --file docket.yaml --file docket.full.yaml config]
[docket] up [docker-compose --file docket.yaml --file docket.full.yaml --file docket-source-mounts.739064199.yaml up -d]
Creating network "03_redispinger-service_default" with the default driver
Creating 03_redispinger-service_pinger_1 ... done
Creating 03_redispinger-service_tester_1 ... done
Creating 03_redispinger-service_redis_1  ... done
[docket] up finished
[docket] exec [docker-compose --file docket.yaml --file docket.full.yaml --file docket-source-mounts.739064199.yaml exec -T tester go test github.com/bloomberg/docket/testdata/03_redispinger-service -run ^TestService$ -count=1]
ok  	github.com/bloomberg/docket/testdata/03_redispinger-service	0.013s
[docket] exec finished
[docket] down [docker-compose --file docket.yaml --file docket.full.yaml --file docket-source-mounts.739064199.yaml down]
Stopping 03_redispinger-service_redis_1  ... done
Stopping 03_redispinger-service_tester_1 ... done
Stopping 03_redispinger-service_pinger_1 ... done
Removing 03_redispinger-service_redis_1  ... done
Removing 03_redispinger-service_tester_1 ... done
Removing 03_redispinger-service_pinger_1 ... done
Removing network 03_redispinger-service_default
[docket] down finished
PASS
ok  	github.com/bloomberg/docket/testdata/03_redispinger-service	9.696s

Debug mode

"Debug" mode is a bit trickier to get working. Since you might want to run either the test driver or the service in debugging or profiling, there's a bit more setup involved.

                                       redis
                                    +---------+
                                    |         |
go test +---------> service +--------> redis  |
           (HTTP)             (TCP) |         |
                                    +---------+

1. Since I plan to use "debug" mode for a while, I'll cut down on repetition by exporting DOCKET_MODE into my environment:

   $ export DOCKET_MODE=debug

2. I can use the dkt helper to bring up the dependent container.

   $ dkt up -d
   [docket] config [docker-compose --file docket.yaml --file docket.debug.yaml config]
   Running: [docker-compose --file docket.yaml --file docket.debug.yaml up -d]
   Creating network "03_redispinger-service_default" with the default driver
   Creating 03_redispinger-service_redis_1 ... done

3. docket.debug.yaml configures the redis service to publish the default Redis port (6379) to the host. Let's find that ephemeral host port.

   $ dkt port redis 6379
   [docket] config [docker-compose --file docket.yaml --file docket.debug.yaml config]
   Running: [docker-compose --file docket.yaml --file docket.debug.yaml port redis 6379]
   0.0.0.0:32775

4. For this example, I'll just run the service with go run, but you could build and then run the service, or start it in a debugger or with profiling enabled. I'll also background it so I can continue with my tests.

   By default, the service will listen on an ephemeral TCP port and print a message to stdout telling you which port it's using. I'll add a short sleep to give that output a chance to show up.

   $ go run . & sleep 1
   [1] 34070
   Listening on 127.0.0.1:63416

5. I need to set the REDISPINGER_URL environment variable to tell the test driver where to send the HTTP request.

   $ REDISPINGER_URL=http://localhost:63416/?redisAddr=localhost:32775 go test
   [docket] config [docker-compose --file docket.yaml --file docket.debug.yaml config]
   [docket] up [docker-compose --file docket.yaml --file docket.debug.yaml up -d]
   03_redispinger-service_redis_1 is up-to-date
   [docket] up finished
   leaving docker-compose app running...
   PASS
   ok  	.../github.com/bloomberg/docket/testdata/03_redispinger-service	1.147s

   If I want to run my test really quickly, I can unset DOCKET_MODE to skip having docket ensure that my Docker Compose app is up.

   $ DOCKET_MODE= REDISPINGER_URL="http://localhost:63416/?redisAddr=localhost:32775" go test
   PASS
   ok  	.../github.com/bloomberg/docket/testdata/03_redispinger-service	0.019s

6. When I'm done, I'll stop the HTTP service,

   $ kill %1
   [1]+  Terminated: 15          go run .

   clean up the Docker Compose app,

   $ dkt down
   [docket] config [docker-compose --file docket.yaml --file docket.debug.yaml config]
   Running: [docker-compose --file docket.yaml --file docket.debug.yaml down]
   Stopping 03_redispinger-service_redis_1 ... done
   Removing 03_redispinger-service_redis_1 ... done
   Removing network 03_redispinger-service_default

   and clean up my shell environment.

   $ unset DOCKET_MODE