opengeospatial · pvretano · Apr 19, 2021 · Apr 30, 2021 · May 2, 2021
diff --git a/core/18-062.adoc b/core/18-062.adoc
@@ -104,6 +104,8 @@ include::clause_6_overview.adoc[]
 
 include::clause_7_core.adoc[]
 
+include::clause_7d_asynchronous-execution.adoc[]
+
 include::clause_7a_ogc-process-description.adoc[]
 
 include::clause_7b_security-considerations.adoc[]

diff --git a/core/abstract_tests/ATS_class_asynchronous-execution.adoc b/core/abstract_tests/ATS_class_asynchronous-execution.adoc
@@ -0,0 +1,17 @@
+[[ats_asynchronous-execution]]
+[cols="1,4",width="90%"]
+|===
+2+|*Conformance Class*
+2+|http://www.opengis.net/spec/ogcapi-processes-1/1.0/conf/asynchronous-execution
+|Target type |Web API
+|Requirements class |<<rc_core,Requirements Class "Core">>
+|===
+
+==== Asynchronous Execution
+
+include::asynchronous-execution/ATS_prefer-header.adoc[]
+
+include::asynchronous-execution/ATS_job-creation-success-async.adoc[]
+
+include::asynchronous-execution/ATS_job-creation-success-async-header.adoc[]
+
diff --git a/core/abstract_tests/ATS_class_core.adoc b/core/abstract_tests/ATS_class_core.adoc
@@ -55,12 +55,6 @@ include::core/ATS_job-creation-op.adoc[]
 
 include::core/ATS_job-creation-request.adoc[]
 
-include::core/ATS_job-creation-mode.adoc[]
-
-include::core/ATS_job-creation-success-async.adoc[]
-
-include::core/ATS_job-creation-success-async-header.adoc[]
-
 include::core/ATS_job-creation-success-sync.adoc[]
 
 include::core/ATS_job-creation-success-sync-raw.adoc[]

diff --git a/...TS_job-creation-success-async-header.adoc → ...TS_job-creation-success-async-header.adoc b/...TS_job-creation-success-async-header.adoc → ...TS_job-creation-success-async-header.adoc
@@ -1,7 +1,7 @@
-[[ats_core_job-creation-success-header-async]]
+[[ats_asynchronous-execution_job-creation-success-header-async]]
 [width="90%",cols="2,6a"]
 |===
-^|*Abstract Test {counter:ats-id}* |*/conf/core/job-creation-success-header-async*
+^|*Abstract Test {counter:ats-id}* |*/conf/asynchronous-execution/job-creation-success-header-async*
 ^|Test Purpose |Validate the HTTP header for an asynchronously executed job.
 ^|Requirement |<<req_core_job-creation-success-header-async,/req/core/job-creation-success-header-async>>
 ^|Test Method |. Validate that the response contains the 'Location' header.

diff --git a/core/abstract_tests/asynchronous-execution/ATS_job-creation-success-async.adoc b/core/abstract_tests/asynchronous-execution/ATS_job-creation-success-async.adoc
@@ -0,0 +1,9 @@
+[[ats_asynchronous-execution_job-creation-success-async]]
+[width="90%",cols="2,6a"]
+|===
+^|*Abstract Test {counter:ats-id}* |*/conf/asynchronous-execution/job-creation-success-async*
+^|Test Purpose |Validate the result of a job that has been created as a result of a process being execute asynchronously.
+^|Requirement |<<req_core_job-creation-success-async,/req/core/job-creation-success-async>>
+^|Test Method |. Validate that result of the job was returned with an HTTP status code 201.
+. Validate the HTTP headers of the result using the test <<ats_asynchronous-execution_job-creation-success-header-async,/conf/asynchronous-execution/job-creation-success-header-async>>.
+|===
diff --git a/core/abstract_tests/asynchronous-execution/ATS_prefer-header.adoc b/core/abstract_tests/asynchronous-execution/ATS_prefer-header.adoc
@@ -0,0 +1,9 @@
+[[ats_asynchronous-execution_prefer-header]]
+[width="90%",cols="2,6a"]
+|===
+^|*Abstract Test {counter:ats-id}* |*/conf/asynchronous-execution/prefer-header*
+^|Test Purpose |Verify that the server correctly processes the HTTP `Prefer` header.
+^|Requirement |<<req_core_prefer-header,/req/core/prefer-header>>
+^|Test Method |. Create a job according to the test <<ats_core_job-creation-op,/req/core/job-creation-op>> and set the value of the HTTP `Prefer` header according to https://tools.ietf.org/html/rfc7240[RFC 7240] to prefer asynchronous execution.
+. Verify that the server responds according to the test <<ats_asynchronous-execution_job-creation-success-header-async,/conf/asynchronous-execution/job-creation-success-async>>.
+|===
diff --git a/core/abstract_tests/core/ATS_job-creation-mode.adoc b/core/abstract_tests/core/ATS_job-creation-mode.adoc
diff --git a/core/abstract_tests/core/ATS_job-creation-op.adoc b/core/abstract_tests/core/ATS_job-creation-op.adoc
@@ -4,7 +4,7 @@
 ^|*Abstract Test {counter:ats-id}* |*/conf/core/job-creation-op*
 ^|Test Purpose |Validate the creation of a new job.
 ^|Requirement |<<req_core_job-creation-op,/req/core/job-creation-op>>
-^|Test Method |. Issue an HTTP POST request to the URL '/processes/{processID}/execution' for each execution mode according to the test <<ats_core_job-creation-mode, /conf/core/job-creation-mode>>.
+^|Test Method |. Issue an HTTP POST request to the URL '/processes/{processID}/execution'.
 . Validate the contents of the POST request using the test <<ats_core_job-creation-request,/conf/core/job-creation-request>>.
-. Validate the creation of the job according to the execution mode using test <<ats_core_job-creation-mode,/conf/core/job-creation-mode>>.
+. Validate the creation of the job according to the test <<ats_core_job-creation-success-sync,/conf/core/job-creation-success-sync>>.
 |===
diff --git a/core/abstract_tests/core/ATS_job-creation-success-async.adoc b/core/abstract_tests/core/ATS_job-creation-success-async.adoc
diff --git a/core/abstract_tests/core/ATS_job-creation-success-sync.adoc b/core/abstract_tests/core/ATS_job-creation-success-sync.adoc
@@ -2,7 +2,7 @@
 [width="90%",cols="2,6a"]
 |===
 ^|*Abstract Test {counter:ats-id}* |*/conf/core/job-creation-success-sync*
-^|Test Purpose |Validate the result of a job that has been created using the `sync` execution mode.
+^|Test Purpose |Validate the result of creating a job.
 ^|Requirement |<<req_core_job-creation-success-sync,/req/core/job-creation-success-sync>>
 ^|Test Method |. Validate that result of the job was returned with a status code 200.
 . Validate the content of the result using the resource and tests identified in <<sync-success-response>>.

diff --git a/core/annex-ats.adoc b/core/annex-ats.adoc
@@ -10,6 +10,10 @@ OGC Web APIs are not a Web Services in the traditional sense. Rather, they defin
 
 include::abstract_tests/ATS_class_core.adoc[]
 
+=== Conformance Class Asynchronous Execution
+
+include::abstract_tests/ATS_class_asynchronous-execution.adoc[]
+
 === Conformance Class OGC Process Description
 
 include::abstract_tests/ATS_class_ogc-process-description.adoc[]

diff --git a/core/clause_2_conformance.adoc b/core/clause_2_conformance.adoc
@@ -29,6 +29,10 @@ The _Core_ does not mandate the use of any specific process description to
 specify the interface of a process. Instead this standard defines and
 recommends the use of the following conformance class:
 
+* <<rc_asynchronous-execution,Asynchronous Execution>>
+
+The default process execution mode is synchronous.  This class defines requirements for requesting asynchronous execution of a process.
+
 * <<rc_ogc-process-description,OGC Process Description>>
 
 This class defines an information model, encoded in JSON, which may be used to

diff --git a/core/clause_7_core.adoc b/core/clause_7_core.adoc
@@ -329,9 +329,7 @@ Inputs can have a multiplicity greater than 1, which means multiple values can b
 
 include::requirements/core/REQ_job-creation-input-cardinality.adoc[]
 
-A process can be either synchronous or asynchronous. 
-
-include::requirements/core/REQ_job-creation-mode.adoc[]
+include::requirements/core/REQ_default-execute-mode.adoc[]
 
 .The following is an example of an execute request
 [source, json]
@@ -341,14 +339,6 @@ include::examples/json/Execute.json[]
 
 ==== Response
 
-In the case of asynchronous execution, the requirements below apply:
-
-include::requirements/core/REQ_job-creation-success-async.adoc[]
-
-include::requirements/core/REQ_job-creation-success-async-header.adoc[]
-
-For a synchronous execution, the following requirement applies:
-
 include::requirements/core/REQ_job-creation-success-sync.adoc[]
 
 ==== Error situations

diff --git a/core/clause_7d_asynchronous-execution.adoc b/core/clause_7d_asynchronous-execution.adoc
@@ -0,0 +1,44 @@
+== Requirements Class "Asynchronous Execution"
+
+=== Overview
+
+include::requirements/requirements_class_asynchronous-execution.adoc[]
+
+This conformance class defines requirements for requesting asynchronous
+execution of processes.  A client signals its desire for asynchronous 
+execution by following the requirements of this conformance class but the
+decision of whether the processes is executed asynchronously or not is left
+to the discretion of the server.
+
+=== Request
+
+include::requirements/asynchronous-execution/REQ_prefer-header.adoc[]
+
+include::recommendations/asynchronous-execution/REC_async.adoc[]
+
+include::recommendations/asynchronous-execution/REC_auto.adoc[]
+
+Requirement <<req_asynchronous-execution_prefer-header,/req/prefer/header>> specifies how the execution mode preference is indicated using standard HTTP methods.  In some cases, however, it is desireable to support a mechanism to mint URIs that encode this preference into links that can, for example, be embeded into a web page.  This document does not mandate any particular approach for how this is supported by a server.
+
+Since clients simply need to dereference the URI of a link, the specific details of how the execution mode preference is encoded into the URI are not important.  Developers interested in the approach of a particular implementation, for example, to manupliate ("hack") URIs in the browser address bar, can study the API definition.
+
+[NOTE]
+====
+A common approach for encoding the execution mode preference in the URI of a link might be to define a `prefer` query parameter with the same syntax and semantics as the `Prefer` header.
+====
+
+include::requirements/asynchronous-execution/REQ_preference_precedence.adoc[]
+
+=== Response
+
+Based on the value of the `Prefer` header the server may choose to execute a 
+process synchronously or asynchronously.  In the case where the server decides
+to execute the process asynchronously, the following requirements apply:
+
+include::requirements/asynchronous-execution/REQ_job-creation-success.adoc[]
+
+include::requirements/asynchronous-execution/REQ_job-creation-success-header.adoc[]
+
+include::recommendations/asynchronous-execution/REC_response.adoc[]
+
+In the case where the server decides to execute the process synchronously, see requirement <<req_core_job-creation-success-sync,/req/core/job-creation-success-sync>>.
diff --git a/core/examples/json/Execute.json b/core/examples/json/Execute.json
@@ -76,6 +76,5 @@
       "transmissionMode": "value"
     }
   },
-  "response": "document",
-  "mode": "async"
+  "response": "document"
 }
diff --git a/core/openapi/schemas/execute.yaml b/core/openapi/schemas/execute.yaml
@@ -1,7 +1,6 @@
 type: object
 required:
   - outputs
-  - mode
   - response
 properties:
   inputs:
@@ -14,12 +13,6 @@ properties:
   outputs:
     additionalProperties:
       $ref: "output.yaml"
-  mode:
-    type: string
-    enum:
-      - sync
-      - async
-      - auto
   response:
     type: string
     enum:

diff --git a/core/recommendations/asynchronous-execution/REC_async.adoc b/core/recommendations/asynchronous-execution/REC_async.adoc
@@ -0,0 +1,7 @@
+[[rec_prefer_async]]
+[width="90%",cols="2,6a"]
+|===
+^|*Recommendation {counter:rec-id}* |*/rec/prefer/async*
+
+If the client includes the `Prefer` header with a https://tools.ietf.org/html/rfc7240#section-4.1[`respond-async`] Preference, the server SHOULD honor the preference and respond asynchronously.
+|===
diff --git a/core/recommendations/asynchronous-execution/REC_auto.adoc b/core/recommendations/asynchronous-execution/REC_auto.adoc
@@ -0,0 +1,7 @@
+[[rec_prefer_auto]]
+[width="90%",cols="2,6a"]
+|===
+^|*Recommendation {counter:rec-id}* |*/rec/prefer/auto*
+
+If the client includes the `Prefer` header with a https://tools.ietf.org/html/rfc7240#section-4.3[`wait`] Preference, the server SHOULD honor that preference in the decision to respond synchronously or asynchronously.
+|===
diff --git a/core/recommendations/asynchronous-execution/REC_response.adoc b/core/recommendations/asynchronous-execution/REC_response.adoc
@@ -0,0 +1,7 @@
+[[rec_prefer_response]]
+[width="90%",cols="2,6a"]
+|===
+^|*Recommendation {counter:rec-id}* |*/rec/prefer/response*
+
+Clients that specify a value for the `Prefer` HTTP header SHOULD be prepared to either receive a response from the process or a system message indicating that the job is being run asynchronously.
+|===
diff --git a/...EQ_job-creation-success-async-header.adoc → ...tion/REQ_job-creation-success-header.adoc b/...EQ_job-creation-success-async-header.adoc → ...tion/REQ_job-creation-success-header.adoc
@@ -1,7 +1,7 @@
-[[req_core_job-creation-success-header-async]]
+[[req_asynchronous-execution_job-creation-success-header]]
 [width="90%",cols="2,6a"]
 |===
-|*Requirement {counter:req-id}* |/req/core/job-creation-success-header-async +
+|*Requirement {counter:req-id}* |/req/asynchronous-execution/job-creation-success-header +
 
 The 201 response of the operation SHALL return a HTTP header named 'Location' which contains a link to the newly created job.
 |===
diff --git a/core/requirements/asynchronous-execution/REQ_job-creation-success.adoc b/core/requirements/asynchronous-execution/REQ_job-creation-success.adoc
@@ -0,0 +1,8 @@
+[[req_asynchronous-execution_job-creation-success-async]]
+[width="90%",cols="2,6a"]
+|===
+|*Requirement {counter:req-id}* |/req/asynchronous-execution/job-creation-success-async +
+
+A successful execution of the operation SHALL be reported as a response with a
+HTTP status code 201.
+|===
diff --git a/core/requirements/asynchronous-execution/REQ_prefer-header.adoc b/core/requirements/asynchronous-execution/REQ_prefer-header.adoc
@@ -0,0 +1,7 @@
+[[req_asynchronous-execution_prefer-header]]
+[width="90%",cols="2,6a"]
+|===
+|*Requirement {counter:req-id}* |/req/asynchronous-execution/prefer-header +
+
+Servers that implement this conformance class SHALL support the HTTP `Prefer` header as defined in https://tools.ietf.org/html/rfc7240[RFC 7240].
+|===
diff --git a/core/requirements/asynchronous-execution/REQ_preference_precedence.adoc b/core/requirements/asynchronous-execution/REQ_preference_precedence.adoc
@@ -0,0 +1,7 @@
+[[req_asynchronous-execution_preference_precedencej]]
+[width="90%",cols="2,6a"]
+|===
+|*Requirement {counter:req-id}* |/req/asynchronous-execution/preference_precedence +
+
+In the case where the execution mode preference is encoded in the URI of a link and is also specified using the HTTP `Prefer` header, then the preference encoded in the link SHALL take precedence.
+|===
diff --git a/core/requirements/core/REQ_default-execute-mode.adoc b/core/requirements/core/REQ_default-execute-mode.adoc
@@ -0,0 +1,7 @@
+[[req_core_default-execute-mode]]
+[width="90%",cols="2,6a"]
+|===
+|*Requirement {counter:req-id}* |/req/core/default-execute-mode +
+
+The default execution mode for a process SHALL be `synchronous` execution.
+|===
diff --git a/core/requirements/core/REQ_job-creation-mode.adoc b/core/requirements/core/REQ_job-creation-mode.adoc
diff --git a/core/requirements/core/REQ_job-creation-success-async.adoc b/core/requirements/core/REQ_job-creation-success-async.adoc
diff --git a/core/requirements/requirements_class_asynchronous-execution.adoc b/core/requirements/requirements_class_asynchronous-execution.adoc
@@ -0,0 +1,9 @@
+[[rc_asynchronous-execution]]
+[cols="1,4",width="90%"]
+|===
+2+|*Requirements Class*
+2+|http://www.opengis.net/spec/ogcapi-processes-1/1.0/req/asynchronous-execution
+|Target type |Web API
+|Dependency |http://www.opengis.net/spec/ogcapi_common-1/1.0/req/core[API - Common Core]
+|Dependency |<<rfc7240,RFC 7240 (Prefer Header for HTTP)>>
+|===