docs/howto: fix fetch-data-over-http flake

This updates /docs/howto/fetch-json-data-http so that it fetches its example JSON data from a local server whilst displaying a publically-available URL on the rendered page. The preprocessor pattern/replacement system is used to perform the switch, instead of swapping out the file with a hidden upload behind the scenes, in order to ensure that the tool file presented is being tested in CI. Fixes cue-lang/cue#3359 Preview-Path: /docs/howto/fetch-json-data-http/ Signed-off-by: Jonathan Matthews <[email protected]> Change-Id: Idc532da6cc8a40c1f1c793b2c4c26ae1db436bd8 Dispatch-Trailer: {"type":"trybot","CL":1199216,"patchset":2,"ref":"refs/changes/16/1199216/2","targetBranch":"master"}
cue-lang · Aug 12, 2024 · c925e37 · c925e37
1 parent 590f6a5
commit c925e37
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diff --git a/content/docs/howto/fetch-json-data-http/en.md b/content/docs/howto/fetch-json-data-http/en.md
@@ -7,17 +7,56 @@ tags:
 - workflow command
 ---
 
+{{{with _script_ "en" "HIDDEN: set caches to speed up re-running"}}}
+export GOMODCACHE=/caches/gomodcache
+export GOCACHE=/caches/gobuild
+{{{end}}}
+
+{{{with _upload_ "en" "HIDDEN: server.go"}}}
+-- server.go --
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// Mirror of https://proxy.golang.org/cached-only/cuelang.org/go/@v/v0.8.2.info
+var response = `{"Version":"v0.8.2","Time":"2024-04-26T11:47:18Z","Origin":{"VCS":"git","URL":"https://review.gerrithub.io/cue-lang/cue","Ref":"refs/tags/v0.8.2","Hash":"596c99191ad1eb7c39d547e59bc7085751d7952b"}}`
+var hostport = "{{{.HOSTPORT}}}"
+
+func main() {
+	fmt.Println("Starting server on " + hostport)
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, response)
+	})
+
+	if err := http.ListenAndServe(hostport, nil); err != nil {
+		fmt.Println("Server failed:", err)
+	}
+}
+{{{end}}}
+
+{{{with _script_ "en" "HIDDEN: go run server"}}}
+# TODO: This is technically racey, but we adopt the same posture as
+# https://cuelang.org/cl/1176732: let's wait for it to actually become a
+# problem before we worry about it. That said, we do build the executable
+# before running it (instead of "go run server.go") to try and /help/ avoid an
+# HTTP connection being attempted before the server is listening.
+go build server.go
+nohup ./server > /tmp/howto-fetch-json-data-http.log 2>&1 &
+sleep 1
+rm server
+{{{end}}}
+
 This guide demonstrates how to use a CUE workflow command to fetch some JSON over HTTP.
 
 It is converted from its JSON representation into data,
 which is then used by the workflow command.
 
 <!-- TODO: consider demonstrating a validation failure when https://github.com/cue-lang/cue/issues/3186 is resolved -->
 
-{{{with code "en" "cc"}}}
-#location top bottom
-exec cue cmd info
-cmp stdout out
+{{{with upload "en" "cc"}}}
 -- a_tool.cue --
 package example
 
@@ -29,7 +68,7 @@ import (
 
 command: info: {
 	fetch: http.Get & {
-		url: "https://proxy.golang.org/cached-only/cuelang.org/go/@v/v0.8.2.info"
+		url: "{{{.URI}}}"
 	}
 	display: cli.Print & {
 		_data: #info & json.Unmarshal(fetch.response.body)
@@ -47,8 +86,10 @@ command: info: {
 	}
 	...
 }
--- out --
-CUE version v0.8.2 was released with commit hash 596c99191ad1eb7c39d547e59bc7085751d7952b
+{{{end}}}
+
+{{{with script "en" "command"}}}
+cue cmd info
 {{{end}}}
 
 ## Related content

diff --git a/content/docs/howto/fetch-json-data-http/gen_cache.cue b/content/docs/howto/fetch-json-data-http/gen_cache.cue
@@ -6,8 +6,58 @@ package site
 				"fetch-json-data-http": {
 					page: {
 						cache: {
-							code: {
-								cc: "/fGkdvJxXOT35Y7SNskPvdKPhPv5VyWGtu35bO7HM0U="
+							upload: {
+								"HIDDEN: server.go": "JHkx7wmlvN9Mm/e5Njc45zyl9qA5nsCe639Kd9nReB4="
+								cc:                  "Myu8x8nfORuqACXzx+RW+VccQ7BgUhkzR+FfCPvCdyA="
+							}
+							multi_step: {
+								hash:       "1LV2P49HO59VUT3PJIASINTAO98F97PLBHTRSNQ978SPNRVUN000===="
+								scriptHash: "HFFNH43U957JTQV8V6FJPCNFU0132TPRFDVKPL6ILOUIJKE4S4HG===="
+								steps: [{
+									doc:      ""
+									cmd:      "export GOMODCACHE=/caches/gomodcache"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc:      ""
+									cmd:      "export GOCACHE=/caches/gobuild"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc: """
+											# TODO: This is technically racey, but we adopt the same posture as
+											# https://cuelang.org/cl/1176732: let's wait for it to actually become a
+											# problem before we worry about it. That said, we do build the executable
+											# before running it (instead of "go run server.go") to try and /help/ avoid an
+											# HTTP connection being attempted before the server is listening.
+											"""
+									cmd:      "go build server.go"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc:      ""
+									cmd:      "nohup ./server >/tmp/howto-fetch-json-data-http.log 2>&1 &"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc:      ""
+									cmd:      "sleep 1"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc:      ""
+									cmd:      "rm server"
+									exitCode: 0
+									output:   ""
+								}, {
+									doc:      ""
+									cmd:      "cue cmd info"
+									exitCode: 0
+									output: """
+											CUE version v0.8.2 was released with commit hash 596c99191ad1eb7c39d547e59bc7085751d7952b
+
+											"""
+								}]
 							}
 						}
 					}

diff --git a/content/docs/howto/fetch-json-data-http/page.cue b/content/docs/howto/fetch-json-data-http/page.cue
@@ -1,3 +1,14 @@
 package site
 
-content: docs: howto: "fetch-json-data-http": page: _
+content: docs: howto: "fetch-json-data-http": page: {
+	vars: {
+		// A random /32+port from the loopback's 127.0.0.1/8 to reduce the chance
+		// of pages with network listeners colliding (if indeed they even share the
+		// IP range, because Docker).
+		HOSTPORT: "127.1.2.3:4567"
+		URI: {
+			pattern:     "http://\(HOSTPORT)/"
+			replacement: "https://proxy.golang.org/cached-only/cuelang.org/go/@v/v0.8.2.info"
+		}
+	}
+}
diff --git a/hugo/content/en/docs/howto/fetch-json-data-http/index.md b/hugo/content/en/docs/howto/fetch-json-data-http/index.md
@@ -15,7 +15,7 @@ which is then used by the workflow command.
 <!-- TODO: consider demonstrating a validation failure when https://github.com/cue-lang/cue/issues/3186 is resolved -->
 
 {{< code-tabs >}}
-{{< code-tab name="a_tool.cue" language="cue" area="top" >}}
+{{< code-tab name="a_tool.cue" language="cue" area="top-left" >}}
 package example
 
 import (
@@ -44,12 +44,12 @@ command: info: {
 	}
 	...
 }
-{{< /code-tab >}}
-{{< code-tab name="TERMINAL" language="" area="bottom" type="terminal" codetocopy="Y3VlIGNtZCBpbmZv" >}}
+{{< /code-tab >}}{{< /code-tabs >}}
+
+```text { title="TERMINAL" type="terminal" codeToCopy="Y3VlIGNtZCBpbmZv" }
 $ cue cmd info
 CUE version v0.8.2 was released with commit hash 596c99191ad1eb7c39d547e59bc7085751d7952b
-{{< /code-tab >}}
-{{< /code-tabs >}}
+```
 
 ## Related content