[concourse] Add support for build_log_retention attribute

See: https://github.com/spring-projects/sts4/issues/389

headless-services/concourse-language-server/src/main/java/org/springframework/ide/vscode/concourse/PipelineYmlSchema.java

@@ -405,12 +405,18 @@ public class PipelineYmlSchema implements YamlSchema {
 		}
 		models.setStepType(step);
 
+		YBeanType t_retention_config = f.ybean("RetentionConfig");
+		addProp(t_retention_config, "days", t_pos_integer);
+		addProp(t_retention_config, "builds", t_pos_integer);
+		addProp(t_retention_config, "minimum_succeeded_builds", t_pos_integer);
+
 		AbstractType job = f.ybean("Job");
 		addProp(job, "name", jobNameDef).isPrimary(true);
 		addProp(job, "old_name", t_ne_string);
 		addProp(job, "plan", f.yseq(step)).isRequired(true);
 		addProp(job, "serial", t_boolean);
-		addProp(job, "build_logs_to_retain", t_pos_integer);
+		addProp(job, "build_logs_to_retain", t_pos_integer).isDeprecated("Deprecated in favor of `build_log_retention`");
+		addProp(job, "build_log_retention", t_retention_config);
 		addProp(job, "serial_groups", t_strings);
 		addProp(job, "max_in_flight", t_pos_integer);
 		addProp(job, "public", t_boolean);

headless-services/concourse-language-server/src/main/resources/desc/Job/build_log_retention.md

@@ -0,0 +1,21 @@
+*Optional*. Configures the retention policy for build logs. This is useful if you have a job that runs often but after
+some amount of time the logs aren't worth keeping around.
+
+The following fields may be specified: `days`, `builds`, `minimum_succeeded_builds`.
+
+Builds which are not retained by one of the above configurations will have their logs reaped.
+
+The following example will keep logs for any builds that have completed in the last 2 days, while also keeping the last 1000 builds, with at least one successful build.
+
+    jobs:
+    - name: smoke-tests
+      build_log_retention:
+        days: 2
+        builds: 1000
+        minimum_succeeded_builds: 1
+      plan:
+      - get: 10m
+      - task: smoke-tests
+        # ...
+
+Note: if more than 1000 builds finish in the past 2 days, all of them will be retained thanks to the build_log_retention.days configuration. Similarly, if there are 1000 builds spanning more than 2 days, they will also be kept thanks to the build_log_retention.builds configuration. And if they all happened to have failed, the build_log_retention.minimum_succeeded_builds will keep around at least one successful build. All policies operate independently.

headless-services/concourse-language-server/src/main/resources/desc/Job/build_logs_to_retain.html

@@ -1,10 +0,0 @@
-<p><em>Optional.</em> If configured, only the last specified number of builds
-will have their build logs persisted. This is useful if you have a job that
-runs periodically but after some amount of time the logs aren't worth keeping
-around.</p><p>Example:</p><div class="highlight"><pre class="verbatim"><span class="t"></span><span class="t"></span><span class="t"></span><span class="nv"></span><span class="py">jobs</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"></span><span class="t"></span><span class="t">
-</span><span class="t"></span><span class="pi">-</span><span class="t"></span><span class="t"> </span><span class="t"></span><span class="nv"></span><span class="py">name</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"> </span><span class="nv"></span><span class="nv">smoke-tests</span><span class="t">
-</span><span class="t">  </span><span class="t"></span><span class="t"></span><span class="t"></span><span class="t"></span><span class="nv"></span><span class="py">build_logs_to_retain</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"> </span><span class="mi">100</span><span class="t"></span><span class="t"></span><span class="t">
-</span><span class="t">  </span><span class="t"></span><span class="t"></span><span class="nv"></span><span class="py">plan</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"></span><span class="t"></span><span class="t">
-</span><span class="t">  </span><span class="pi">-</span><span class="t"></span><span class="t"> </span><span class="t"></span><span class="nv"></span><span class="py">get</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"> </span><span class="mi">10</span><span class="nv"></span><span class="nv">m</span><span class="t">
-</span><span class="t">  </span><span class="t"></span><span class="t"></span><span class="pi">-</span><span class="t"></span><span class="t"> </span><span class="t"></span><span class="nv"></span><span class="py">task</span><span class="t"></span><span class="pi">:</span><span class="t"></span><span class="t"> </span><span class="nv"></span><span class="nv">smoke-tests</span><span class="t">
-</span><span class="t">    </span><span class="nv">#</span><span class="sp"> </span><span class="nv">...</span></pre></div>

headless-services/concourse-language-server/src/main/resources/desc/Job/build_logs_to_retain.md

@@ -0,0 +1,6 @@
+*Optional*. Deprecated in favor of `build_log_retention`.
+
+Equivalent to the following:
+
+    build_log_retention:
+      builds: number

headless-services/concourse-language-server/src/main/resources/desc/RetentionConfig/builds.md

@@ -0,0 +1 @@
+*Optional*. Keep logs for the last specified number of builds

headless-services/concourse-language-server/src/main/resources/desc/RetentionConfig/days.md

@@ -0,0 +1 @@
+*Optional*. Keep logs for builds which have finished within the specified number of days.

headless-services/concourse-language-server/src/main/resources/desc/RetentionConfig/minimum_succeeded_builds.md

@@ -0,0 +1 @@
+*Optional*. Keep logs for at least N successful builds.