talking to testnet and painting bikeshed

.gitignore

@@ -1,3 +1,4 @@
 *.swp
 *.swo
 *.beam
+erl_crash.dump

README.md

@@ -1031,3 +1031,129 @@ index 44d206d..3abd46f 100644
 +slogan(404) -> "Not Found";
 +slogan(500) -> "Internal Server Error".
 ```
+
+## Video 2: Talking to the gm testnet (2025-09-25)
+
+- 
+
+### Adding hz as a dependency
+
+- [`hakuzaru`](https://git.qpq.swiss/QPQ-AG/hakuzaru/) is our Erlang
+  \[application\] (applications are the subset of what in another language you
+  would call "libraries" that spawn processes, essentially...) for talking to
+  the blockchain from an Erlang application.
+
+```
+$ zx list versions hakuzaru
+0.6.1
+0.6.0
+0.5.2
+0.5.1
+0.5.0
+0.4.0
+0.3.2
+0.3.1
+0.3.0
+0.2.0
+0.1.0
+$ zx set dep otpr-hakuzaru-0.6.1
+```
+
+If we just try to use this naively, we will run into errors whenever we try to
+call code that calls into hz's dependencies.
+
+So we also have to manually include all of hz's dependencies.
+
+Thankfully, hz is also subject to this same constraint, so we only have to just
+copy them from hz's zomp.meta file.
+
+```diff
+diff --git a/gex_httpd/zomp.meta b/gex_httpd/zomp.meta
+index 442e32e..eb32a14 100644
+--- a/gex_httpd/zomp.meta
++++ b/gex_httpd/zomp.meta
+@@ -5,7 +5,18 @@
+ {author,"Peter Harpending"}.
+ {desc,"Gajumaru Exchange HTTP Daemon"}.
+ {package_id,{"otpr","gex_httpd",{0,1,0}}}.
+-{deps,[{"otpr","hakuzaru",{0,6,1}},{"otpr","qhl",{0,1,0}}]}.
++{deps,[
++    {"otpr","hakuzaru",{0,6,1}},
++       {"otpr","sophia",{9,0,0}},
++       {"otpr","gmserialization",{0,1,3}},
++       {"otpr","gmbytecode",{3,4,1}},
++       {"otpr","base58",{0,1,1}},
++       {"otpr","eblake2",{1,0,1}},
++       {"otpr","ec_utils",{1,0,0}},
++       {"otpr","zj",{1,1,0}},
++       {"otpr","getopt",{1,0,2}},
++    {"otpr","qhl",{0,1,0}}
++]}.
+ {key_name,none}.
+ {a_email,"peterharpending@qpq.swiss"}.
+ {c_email,"peterharpending@qpq.swiss"}.
+```
+
+### talking to testnet
+
+```diff
+diff --git a/gex_httpd/src/gex_httpd.erl b/gex_httpd/src/gex_httpd.erl
+index 3a724b0..a2ed213 100644
+--- a/gex_httpd/src/gex_httpd.erl
++++ b/gex_httpd/src/gex_httpd.erl
+@@ -69,10 +69,28 @@ start() ->
+ start(normal, _Args) ->
+     Result = gh_sup:start_link(),
+     % auto-listen to port 8000
++    ok = hz(),
+     ok = listen(8000),
++    ok = io:format("~p~n", [hz:status()]),
+     Result.
+
+
++hz() ->
++    ok = application:ensure_started(hakuzaru),
++    ok = hz:chain_nodes([testnet_node()]),
++    ok = zx:tell("hz status: ~tp", [hz:status()]),
++    ok.
++
++testnet_ip() ->
++    {84, 46, 242, 9}.
++
++testnet_port() ->
++    3013.
++
++testnet_node() ->
++    {testnet_ip(), testnet_port()}.
++
++
+ -spec stop(term()) -> ok.
+ %% @private
+ %% Similar to start/2 above, this is to be called by the "application" part of OTP,
+```
+
+```erlang
+hz status: {ok,#{"difficulty" => 3172644578,
+                 "finalized" =>
+                     #{"hash" =>
+                           "kh_2vPQ8Q8QYQF1tSWRrSjPJ5YKSCfLD4TKEfeAvuNsdkWzVkFspp",
+                       "height" => 215186,"type" => "height"},
+                 "genesis_key_block_hash" =>
+                     "kh_Qdi5MTuuhJm7xzn5JUAbYG12cX3qoLMnXrBxPGzBkMWJ4K8vq",
+                 "hashrate" => 953086,"listening" => true,
+                 "network_id" => "groot.testnet",
+                 "node_revision" => "7b3cc1db3bb36053023167b86f7d6f2d5dcbd01d",
+                 "node_version" => "0.1.0+203.7b3cc1db3",
+                 "peer_connections" => #{"inbound" => 1,"outbound" => 3},
+                 "peer_count" => 4,
+                 "peer_pubkey" =>
+                     "pp_2nQHucGyEt5wkYruNuRkg19cbZuEeyR9BZfvtv49F3AoyNSYMT",
+                 "pending_transactions_count" => 0,
+                 "protocols" => [#{"effective_at_height" => 0,"version" => 1}],
+                 "solutions" => 0,"sync_progress" => 100.0,"syncing" => false,
+                 "top_block_height" => 215287,
+                 "top_hash" =>
+                     "kh_2TX5p81WtTX3y82NPdfWwv7yuehDh6aMRh1Uy6GBS5JsdkaGXu",
+                 "top_key_block_hash" =>
+                     "kh_2TX5p81WtTX3y82NPdfWwv7yuehDh6aMRh1Uy6GBS5JsdkaGXu"}}
+```

gex_httpd/src/gex_httpd.erl

@@ -69,10 +69,27 @@ start() ->
 start(normal, _Args) ->
     Result = gh_sup:start_link(),
     % auto-listen to port 8000
+    ok = hz(),
     ok = listen(8000),
     Result.
 
 
+hz() ->
+    ok = application:ensure_started(hakuzaru),
+    ok = hz:chain_nodes([testnet_node()]),
+    ok = zx:tell("hz status: ~tp", [hz:status()]),
+    ok.
+
+testnet_ip() ->
+    {84, 46, 242, 9}.
+
+testnet_port() ->
+    3013.
+
+testnet_node() ->
+    {testnet_ip(), testnet_port()}.
+
+
 -spec stop(term()) -> ok.
 %% @private
 %% Similar to start/2 above, this is to be called by the "application" part of OTP,

gex_httpd/zomp.meta

@@ -5,7 +5,18 @@
 {author,"Peter Harpending"}.
 {desc,"Gajumaru Exchange HTTP Daemon"}.
 {package_id,{"otpr","gex_httpd",{0,1,0}}}.
-{deps,[{"otpr","qhl",{0,1,0}}]}.
+{deps,[
+    {"otpr","hakuzaru",{0,6,1}},
+       {"otpr","sophia",{9,0,0}},
+       {"otpr","gmserialization",{0,1,3}},
+       {"otpr","gmbytecode",{3,4,1}},
+       {"otpr","base58",{0,1,1}},
+       {"otpr","eblake2",{1,0,1}},
+       {"otpr","ec_utils",{1,0,0}},
+       {"otpr","zj",{1,1,0}},
+       {"otpr","getopt",{1,0,2}},
+    {"otpr","qhl",{0,1,0}}
+]}.
 {key_name,none}.
 {a_email,"peterharpending@qpq.swiss"}.
 {c_email,"peterharpending@qpq.swiss"}.