Enable overriding the API port number

Using an environment variable called BISQ_API_PORT, it is now possible
to override the default API port of 8080 to whichever available port
desired.

This enables running the API on a machine where port 8080 is occupied,
it also enables running multiple Bisq instances side-by-side with their
respective API's enabled.

Signed-off-by: Mike Rosseel <mike.rosseel@gmail.com>

api/Readme.md

@@ -1,5 +1,12 @@
-current api docs are at:
-https://github.com/dan-da/bitsquare/blob/rpc_api/doc/api/README.md
+# Bisq API
+
+*Based on proposal XX*
+
+## Enabling the api
+
+--enableApi true
+
+## Exploring the REST API
 
 generated swagger docs are at:
 http://localhost:8080/swagger
@@ -7,5 +14,14 @@ http://localhost:8080/swagger
 swagger.json can be found at (generate clients with swagger editor):
 http://localhost:8080/swagger.json
 
+the admin interface can be found at:
+http://localhost:8080/admin[
+
+## Overriding http port
+
+Set an environment variable called "BISQ_API_PORT" to your desired port.
+
+## TODO
+
 Candidate for hosting the docs:
 https://github.com/Rebilly/ReDoc

api/src/main/java/io/bisq/api/service/DropwizardApplication.java

@@ -17,7 +17,9 @@ import io.bisq.core.user.Preferences;
 import io.bisq.core.user.User;
 import io.bisq.network.p2p.P2PService;
 import io.dropwizard.Application;
+import io.dropwizard.configuration.EnvironmentVariableSubstitutor;
 import io.dropwizard.configuration.ResourceConfigurationSourceProvider;
+import io.dropwizard.configuration.SubstitutingSourceProvider;
 import io.dropwizard.setup.Bootstrap;
 import io.dropwizard.setup.Environment;
 import io.federecio.dropwizard.swagger.SwaggerBundle;
@@ -81,6 +83,13 @@ public class DropwizardApplication extends Application<ApiConfiguration> {
                 return configuration.swaggerBundleConfiguration;
             }
         });
+        // Overriding settings through environment variables, added to override the http port from 8080 to something else
+        // See http://www.dropwizard.io/1.1.4/docs/manual/core.html#configuration
+        bootstrap.setConfigurationSourceProvider(
+                new SubstitutingSourceProvider(bootstrap.getConfigurationSourceProvider(),
+                        new EnvironmentVariableSubstitutor(false)
+                )
+        );
     }
 
     @Override

api/src/main/resources/bisq-api.yml

@@ -4,3 +4,12 @@ defaultName: Stranger
 # the only required property is resourcePackage, for more config options see below
 swagger:
   resourcePackage: io.bisq.api.service
+
+
+server:
+  type: simple
+  applicationContextPath: /
+  adminContextPath: /admin
+  connector:
+    type: http
+    port: ${BISQ_API_PORT:-8080}