made tutorial outputs more presentable (#555)

Closes https://github.com/ooni/probe/issues/1831

internal/tutorial/measurex/chapter01/README.md

@@ -190,9 +190,10 @@ Let us run the program with default arguments first. You can do
 this operation by running:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter01
+go run -race ./internal/tutorial/measurex/chapter01 | jq
 ```
 
+Where `jq` is being used to make the output more presentable.
 If you do that you obtain some logging messages, which are out of
 the scope of this tutorial, and the following JSON:
 
@@ -257,7 +258,7 @@ Let us now change the domain to resolve to be `antani.ooni.org` (a
 nonexisting domain), which we can do by running this command:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter01 -domain antani.ooni.org
+go run -race ./internal/tutorial/measurex/chapter01 -domain antani.ooni.org | jq
 ```
 
 This is the output JSON:
@@ -318,7 +319,7 @@ top of which `measurex` is written.)
 Let us now try with an insanely low timeout:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter01 -timeout 250us
+go run -race ./internal/tutorial/measurex/chapter01 -timeout 250us | jq
 ```
 
 To get this JSON:

internal/tutorial/measurex/chapter01/main.go

@@ -191,9 +191,10 @@ func main() {
 // this operation by running:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter01
+// go run -race ./internal/tutorial/measurex/chapter01 | jq
 // ```
 //
+// Where `jq` is being used to make the output more presentable.
 // If you do that you obtain some logging messages, which are out of
 // the scope of this tutorial, and the following JSON:
 //
@@ -258,7 +259,7 @@ func main() {
 // nonexisting domain), which we can do by running this command:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter01 -domain antani.ooni.org
+// go run -race ./internal/tutorial/measurex/chapter01 -domain antani.ooni.org | jq
 // ```
 //
 // This is the output JSON:
@@ -319,7 +320,7 @@ func main() {
 // Let us now try with an insanely low timeout:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter01 -timeout 250us
+// go run -race ./internal/tutorial/measurex/chapter01 -timeout 250us | jq
 // ```
 //
 // To get this JSON:

internal/tutorial/measurex/chapter02/README.md

@@ -85,7 +85,7 @@ Let us run the program with default arguments first. You can do
 this operation by running:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter02
+go run -race ./internal/tutorial/measurex/chapter02 | jq
 ```
 
 Here is the JSON we obtain in output:
@@ -129,7 +129,7 @@ Let us now see if we can provoke some errors and timeouts.
 Let us start with an IP address where there's no listening socket:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter02 -address 127.0.0.1:1
+go run -race ./internal/tutorial/measurex/chapter02 -address 127.0.0.1:1 | jq
 ```
 
 We get this JSON:
@@ -161,7 +161,7 @@ the oddity that classifies the error.
 Let us now try to obtain a timeout:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1
+go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 | jq
 ```
 
 We get this JSON:
@@ -192,7 +192,7 @@ precise than just the error alone.
 Let us now use a very small timeout:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 -timeout 100ms
+go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 -timeout 100ms | jq
 ```
 
 To get this JSON:

internal/tutorial/measurex/chapter02/main.go

@@ -86,7 +86,7 @@ func main() {
 // this operation by running:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter02
+// go run -race ./internal/tutorial/measurex/chapter02 | jq
 // ```
 //
 // Here is the JSON we obtain in output:
@@ -130,7 +130,7 @@ func main() {
 // Let us start with an IP address where there's no listening socket:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter02 -address 127.0.0.1:1
+// go run -race ./internal/tutorial/measurex/chapter02 -address 127.0.0.1:1 | jq
 // ```
 //
 // We get this JSON:
@@ -162,7 +162,7 @@ func main() {
 // Let us now try to obtain a timeout:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1
+// go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 | jq
 // ```
 //
 // We get this JSON:
@@ -193,7 +193,7 @@ func main() {
 // Let us now use a very small timeout:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 -timeout 100ms
+// go run -race ./internal/tutorial/measurex/chapter02 -address 8.8.4.4:1 -timeout 100ms | jq
 // ```
 //
 // To get this JSON:

internal/tutorial/measurex/chapter03/README.md

@@ -69,7 +69,7 @@ we print using the usual three-liner.
 As before, let us start off with a vanilla run:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter03
+go run -race ./internal/tutorial/measurex/chapter03 | jq
 ```
 
 This time we get a much larger JSON, so I will pretend it is
@@ -246,7 +246,7 @@ output JSON changes because of them.
 Let us try to get a NXDOMAIN error.
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter03 -query antani.ooni.org
+go run -race ./internal/tutorial/measurex/chapter03 -query antani.ooni.org | jq
 ```
 
 This produces the following JSON:
@@ -443,7 +443,7 @@ Let us now try to get a REFUSED DNS Rcode, again from servers
 that are, let's say, kind enough to easily help.
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter03 -address 180.97.36.63:53
+go run -race ./internal/tutorial/measurex/chapter03 -address 180.97.36.63:53 | jq
 ```
 
 Here's the answer I get:

internal/tutorial/measurex/chapter03/main.go

@@ -70,7 +70,7 @@ func main() {
 // As before, let us start off with a vanilla run:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter03
+// go run -race ./internal/tutorial/measurex/chapter03 | jq
 // ```
 //
 // This time we get a much larger JSON, so I will pretend it is
@@ -247,7 +247,7 @@ func main() {
 // Let us try to get a NXDOMAIN error.
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter03 -query antani.ooni.org
+// go run -race ./internal/tutorial/measurex/chapter03 -query antani.ooni.org | jq
 // ```
 //
 // This produces the following JSON:
@@ -444,7 +444,7 @@ func main() {
 // that are, let's say, kind enough to easily help.
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter03 -address 180.97.36.63:53
+// go run -race ./internal/tutorial/measurex/chapter03 -address 180.97.36.63:53 | jq
 // ```
 //
 // Here's the answer I get:

internal/tutorial/measurex/chapter04/README.md

@@ -80,7 +80,7 @@ the measurement itself, which we print below.
 As before, let us start off with a vanilla run:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter04
+go run -race ./internal/tutorial/measurex/chapter04 | jq
 ```
 
 Let us comment the JSON in detail:
@@ -209,13 +209,13 @@ changes in different error conditions.
 
 Here are the commands I used for each proposed exercise:
 
-1. go run -race ./internal/tutorial/measurex/chapter04 -address 8.8.4.4:1
+1. go run -race ./internal/tutorial/measurex/chapter04 -address 8.8.4.4:1 | jq
 
-2. go run -race ./internal/tutorial/measurex/chapter04 -sni example.org
+2. go run -race ./internal/tutorial/measurex/chapter04 -sni example.org | jq
 
-3. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni self-signed.badssl.com
+3. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni self-signed.badssl.com | jq
 
-4. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni expire.badssl.com
+4. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni expire.badssl.com | jq
 
 To emulate the last two scenarios, if you're on Linux, a
 possibility is building Jafar with this command:

internal/tutorial/measurex/chapter04/main.go

@@ -81,7 +81,7 @@ func main() {
 // As before, let us start off with a vanilla run:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter04
+// go run -race ./internal/tutorial/measurex/chapter04 | jq
 // ```
 //
 // Let us comment the JSON in detail:
@@ -193,7 +193,7 @@ func main() {
 // ### Suggested follow-up experiments
 //
 // Try to run experiments in the following scenarios, and
-// check the output JSON to familiarize yourself with what 
+// check the output JSON to familiarize yourself with what
 // changes in different error conditions.
 //
 // 1. measurement that causes timeout
@@ -210,13 +210,13 @@ func main() {
 //
 // Here are the commands I used for each proposed exercise:
 //
-// 1. go run -race ./internal/tutorial/measurex/chapter04 -address 8.8.4.4:1
+// 1. go run -race ./internal/tutorial/measurex/chapter04 -address 8.8.4.4:1 | jq
 //
-// 2. go run -race ./internal/tutorial/measurex/chapter04 -sni example.org
+// 2. go run -race ./internal/tutorial/measurex/chapter04 -sni example.org | jq
 //
-// 3. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni self-signed.badssl.com
+// 3. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni self-signed.badssl.com | jq
 //
-// 4. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni expire.badssl.com
+// 4. go run -race ./internal/tutorial/measurex/chapter04 -address 104.154.89.105:443 -sni expire.badssl.com | jq
 //
 // To emulate the last two scenarios, if you're on Linux, a
 // possibility is building Jafar with this command:

internal/tutorial/measurex/chapter05/README.md

@@ -81,7 +81,7 @@ lines of code for printing the resulting measurement.
 As before, let us start off with a vanilla run:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter05
+go run -race ./internal/tutorial/measurex/chapter05 | jq
 ```
 
 Produces this JSON:

internal/tutorial/measurex/chapter05/main.go

@@ -82,7 +82,7 @@ func main() {
 // As before, let us start off with a vanilla run:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter05
+// go run -race ./internal/tutorial/measurex/chapter05 | jq
 // ```
 //
 // Produces this JSON:

internal/tutorial/measurex/chapter06/README.md

@@ -458,19 +458,19 @@ Here are some suggestions for follow up measurements:
 1. provoke a connect error by using:
 
 ```
-go run -race ./internal/tutorial/measurex/chapter06 -address 127.0.0.1:1
+go run -race ./internal/tutorial/measurex/chapter06 -address 127.0.0.1:1 | jq
 ```
 
 2. provoke a TLS handshake error by using:
 
 ```
-go run -race ./internal/tutorial/measurex/chapter06 -sni example.com
+go run -race ./internal/tutorial/measurex/chapter06 -sni example.com | jq
 ```
 
 3. provoke an HTTP round trip error by using:
 
 ```
-go run -race ./internal/tutorial/measurex/chapter06 -address 8.8.8.8:853
+go run -race ./internal/tutorial/measurex/chapter06 -address 8.8.8.8:853 | jq
 ```
 
 4. modify the code to fetch an HTTP endpoint instead (hint: you

internal/tutorial/measurex/chapter06/main.go

@@ -459,19 +459,19 @@ func main() {
 // 1. provoke a connect error by using:
 //
 // ```
-// go run -race ./internal/tutorial/measurex/chapter06 -address 127.0.0.1:1
+// go run -race ./internal/tutorial/measurex/chapter06 -address 127.0.0.1:1 | jq
 // ```
 //
 // 2. provoke a TLS handshake error by using:
 //
 // ```
-// go run -race ./internal/tutorial/measurex/chapter06 -sni example.com
+// go run -race ./internal/tutorial/measurex/chapter06 -sni example.com | jq
 // ```
 //
 // 3. provoke an HTTP round trip error by using:
 //
 // ```
-// go run -race ./internal/tutorial/measurex/chapter06 -address 8.8.8.8:853
+// go run -race ./internal/tutorial/measurex/chapter06 -address 8.8.8.8:853 | jq
 // ```
 //
 // 4. modify the code to fetch an HTTP endpoint instead (hint: you

internal/tutorial/measurex/chapter07/README.md

@@ -124,7 +124,7 @@ Finally, we print the results.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter07
+go run -race ./internal/tutorial/measurex/chapter07 | jq
 ```
 
 Please, check the JSON output. Do you recognize the fields

internal/tutorial/measurex/chapter07/main.go

@@ -125,7 +125,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter07
+// go run -race ./internal/tutorial/measurex/chapter07 | jq
 // ```
 //
 // Please, check the JSON output. Do you recognize the fields

internal/tutorial/measurex/chapter08/README.md

@@ -111,7 +111,7 @@ This is it. The rest of the program is exactly the same.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter08
+go run -race ./internal/tutorial/measurex/chapter08 | jq
 ```
 
 Please, check the JSON output. Do you recognize the fields

internal/tutorial/measurex/chapter08/main.go

@@ -112,7 +112,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter08
+// go run -race ./internal/tutorial/measurex/chapter08 | jq
 // ```
 //
 // Please, check the JSON output. Do you recognize the fields

internal/tutorial/measurex/chapter09/README.md

@@ -112,7 +112,7 @@ our `m` container and we print it.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter09
+go run -race ./internal/tutorial/measurex/chapter09 | jq
 ```
 
 Take a look at the JSON output. Can you spot that

internal/tutorial/measurex/chapter09/main.go

@@ -113,7 +113,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter09
+// go run -race ./internal/tutorial/measurex/chapter09 | jq
 // ```
 //
 // Take a look at the JSON output. Can you spot that

internal/tutorial/measurex/chapter10/README.md

@@ -115,7 +115,7 @@ The rest of the program is exactly like in chapter09.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter10
+go run -race ./internal/tutorial/measurex/chapter10 | jq
 ```
 
 Take a look at the JSON output. Can you spot that

internal/tutorial/measurex/chapter10/main.go

@@ -116,7 +116,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter10
+// go run -race ./internal/tutorial/measurex/chapter10 | jq
 // ```
 //
 // Take a look at the JSON output. Can you spot that

internal/tutorial/measurex/chapter11/README.md

@@ -95,13 +95,13 @@ here on `main` using the `PanicOnError` function.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter11
+go run -race ./internal/tutorial/measurex/chapter11 | jq
 ```
 
 Take a look at the JSON output and compare it with:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com
+go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com | jq
 ```
 
 (which is basically forcing chapter10 to run with the
@@ -114,7 +114,7 @@ and compare it to the code written in chapter10?
 Now run:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com
+go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com | jq
 ```
 
 Do you see the opportunity there for following redirections? :^).

internal/tutorial/measurex/chapter11/main.go

@@ -96,13 +96,13 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter11
+// go run -race ./internal/tutorial/measurex/chapter11 | jq
 // ```
 //
 // Take a look at the JSON output and compare it with:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com
+// go run -race ./internal/tutorial/measurex/chapter10 -url https://www.google.com | jq
 // ```
 //
 // (which is basically forcing chapter10 to run with the
@@ -115,7 +115,7 @@ func main() {
 // Now run:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com
+// go run -race ./internal/tutorial/measurex/chapter11 -url https://google.com | jq
 // ```
 //
 // Do you see the opportunity there for following redirections? :^).

internal/tutorial/measurex/chapter12/README.md

@@ -79,7 +79,7 @@ is closed when done by `MeasureURLAndFollowRedirections`, so we leave the loop.
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter12
+go run -race ./internal/tutorial/measurex/chapter12 | jq
 ```
 
 Take a look at the JSON. You should see several redirects

internal/tutorial/measurex/chapter12/main.go

@@ -80,7 +80,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter12
+// go run -race ./internal/tutorial/measurex/chapter12 | jq
 // ```
 //
 // Take a look at the JSON. You should see several redirects

internal/tutorial/measurex/chapter14/README.md

@@ -250,7 +250,7 @@ func main() {
 Let us perform a vanilla run first:
 
 ```bash
-go run -race ./internal/tutorial/measurex/chapter14
+go run -race ./internal/tutorial/measurex/chapter14 | jq
 ```
 
 Take a look at the JSON.

internal/tutorial/measurex/chapter14/main.go

@@ -251,7 +251,7 @@ func main() {
 // Let us perform a vanilla run first:
 //
 // ```bash
-// go run -race ./internal/tutorial/measurex/chapter14
+// go run -race ./internal/tutorial/measurex/chapter14 | jq
 // ```
 //
 // Take a look at the JSON.