Add documentation of incremental trace update API

[ci skip]

doc/ci/api/builds.md

@@ -26,48 +26,114 @@ This API uses two types of authentication:
 
 ### Runs oldest pending build by runner
 
-    POST /ci/api/v1/builds/register
+```
+POST /ci/api/v1/builds/register
+```
 
-Parameters:
+| Attribute | Type    | Required | Description         |
+|-----------|---------|----------|---------------------|
+| `token`   | string  | yes      | Unique runner token |
 
-  * `token` (required) - Unique runner token
 
+```
+curl -X POST "https://gitlab.example.com/ci/api/v1/builds/register" -F "token=t0k3n"
+```
 
 ### Update details of an existing build
 
-    PUT /ci/api/v1/builds/:id
+```
+PUT /ci/api/v1/builds/:id
+```
+
+| Attribute | Type    | Required | Description          |
+|-----------|---------|----------|----------------------|
+| `id`      | integer | yes      | The ID of a project  |
+| `token`   | string  | yes      | Unique runner token  |
+| `state`   | string  | no       | The state of a build |
+| `trace`   | string  | no       | The trace of a build |
+
+```
+curl -X PUT "https://gitlab.example.com/ci/api/v1/builds/1234" -F "token=t0k3n" -F "state=running" -F "trace=Running git clone...\n"
+```
+
+### Incremental build trace update
+
+Using this method you need to send trace content as a request body. You need also to provide the `Content-Range` header
+with a range of sent trace part. Note, that you need to send parts in a proper order, so the begining of the part
+must starts just after the end of the previous part. If you will mess the parts, then GitLab CI AIP will return `416
+Range Not Satisfiable` response with a header `Range: 0-X`, where `X` is the current trace length.
+
+For example: if you receive `Range: 0-11` in the response, then your next part must contains `Content-Range: 11-...`
+header and a trace part covered by this range.
+
+For a valid update API will return `202` response with:
+* `Build-Status: {status}` header containing current status of the build,
+* `Range: 0-{length}` header with the current trace length.
+
+```
+PATCH /ci/api/v1/builds/:id/trace.txt
+```
 
 Parameters:
 
-  * `id` (required) - The ID of a project
-  * `token` (required) - Unique runner token
-  * `state` (optional) - The state of a build
-  * `trace` (optional) - The trace of a build
+| Attribute | Type    | Required | Description          |
+|-----------|---------|----------|----------------------|
+| `id`      | integer | yes      | The ID of a build    |
+
+Headers:
+
+| Attribute       | Type    | Required | Description                       |
+|-----------------|---------|----------|-----------------------------------|
+| `BUILD-TOKEN`   | string  | yes      | The build authorization token     |
+| `Content-Range` | string  | yes      | Bytes range of trace that is sent |
+
+```
+curl -X PATCH "https://gitlab.example.com/ci/api/v1/builds/1234/trace.txt" -H "BUILD-TOKEN=build_t0k3n" -H "Content-Range=0-21" -d "Running git clone...\n"
+```
+
 
 ### Upload artifacts to build
 
-    POST /ci/api/v1/builds/:id/artifacts
+```
+POST /ci/api/v1/builds/:id/artifacts
+```
 
-Parameters:
+| Attribute | Type    | Required | Description                   |
+|-----------|---------|----------|-------------------------------|
+| `id`      | integer | yes      | The ID of a build             |
+| `token`   | string  | yes      | The build authorization token |
+| `file`    | mixed   | yes      | Artifacts file                |
 
-  * `id` (required) - The ID of a build
-  * `token` (required) - The build authorization token
-  * `file` (required) - Artifacts file
+```
+curl -X POST "https://gitlab.example.com/ci/api/v1/builds/1234/artifacts" -F "token=build_t0k3n" -F "file=@/path/to/file"
+```
 
 ### Download the artifacts file from build
 
-    GET /ci/api/v1/builds/:id/artifacts
+```
+GET /ci/api/v1/builds/:id/artifacts
+```
 
-Parameters:
+| Attribute | Type    | Required | Description                   |
+|-----------|---------|----------|-------------------------------|
+| `id`      | integer | yes      | The ID of a build             |
+| `token`   | string  | yes      | The build authorization token |
 
-  * `id` (required) - The ID of a build
-  * `token` (required) - The build authorization token
+```
+curl "https://gitlab.example.com/ci/api/v1/builds/1234/artifacts" -F "token=build_t0k3n"
+```
 
 ### Remove the artifacts file from build
 
-    DELETE /ci/api/v1/builds/:id/artifacts
+```
+DELETE /ci/api/v1/builds/:id/artifacts
+```
 
-Parameters:
+| Attribute | Type    | Required | Description                   |
+|-----------|---------|----------|-------------------------------|
+| ` id`     | integer | yes      | The ID of a build             |
+| `token`   | string  | yes      | The build authorization token |
 
-  * ` id` (required) - The ID of a build
-  * `token` (required) - The build authorization token
+```
+curl -X DELETE "https://gitlab.example.com/ci/api/v1/builds/1234/artifacts" -F "token=build_t0k3n"
+```

lib/ci/api/builds.rb

@@ -57,7 +57,8 @@ module Ci
         # Body:
         #   content of logs to append
         # Headers:
-        #   Content-Range: range of conntent that was sent
+        #   Content-Range (required) - range of conntent that was sent
+        #   BUILD-TOKEN (required) - The build authorization token
         # Example Request:
         #   PATCH /builds/:id/trace.txt
         patch ":id/trace.txt" do