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Merged
abhilashra merged 4 commits into from
Jan 27, 2026
Merged

Feature/fix imdsv2 changes #1

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1fb6d8f
fixed the imdsv2 changes
abhilashra Jan 11, 2026
70f3efa
Merge branch 'master' into feature/fix-imdsv2-changes
abhilashra Jan 26, 2026
57d10bd
updated the pr
abhilashra Jan 26, 2026
f3e80fe
fixed the issues
abhilashra Jan 26, 2026
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87 changes: 81 additions & 6 deletions src/erlcloud_ec2_meta.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -3,11 +3,15 @@
-include("erlcloud.hrl").
-include("erlcloud_aws.hrl").

-export([generate_session_token/1, generate_session_token/2,
get_instance_metadata/0, get_instance_metadata/1, get_instance_metadata/2, get_instance_metadata/3,
get_instance_user_data/0, get_instance_user_data/1, get_instance_user_data/2,
get_instance_dynamic_data/0, get_instance_dynamic_data/1, get_instance_dynamic_data/2, get_instance_dynamic_data/3]).
-export([get_instance_metadata/0, get_instance_metadata/1, get_instance_metadata/2,
get_instance_user_data/0, get_instance_user_data/1,
get_instance_dynamic_data/0, get_instance_dynamic_data/1, get_instance_dynamic_data/2,
get_imds_token/1]).

-define(IMDS_BASE_URL, "http://169.254.169.254").
-define(IMDS_TOKEN_TTL, 21600). % 6 hours in seconds
-define(IMDS_TOKEN_REFRESH_THRESHOLD, 10800). % 3 hours in seconds
-define(ERLCLOUD_TOKEN_CACHE_KEY, {erlcloud_ec2_meta, imds_token}).

-spec generate_session_token(DurationSecs :: non_neg_integer()) -> {ok, binary()} | {error, erlcloud_aws:httpc_result_error()}.
generate_session_token(DurationSecs) ->
Expand Down Expand Up @@ -51,12 +55,17 @@ get_instance_metadata(ItemPath, Config) ->
%% <host:port> defaults to 169.254.169.254
%%
%%
get_instance_metadata(ItemPath, Config) ->
MetaDataPath = ?IMDS_BASE_URL ++ "/latest/meta-data/" ++ ItemPath,
Headers = get_imds_headers(Config),
Timeout = erlcloud_aws:get_timeout(Config),
erlcloud_aws:http_body(erlcloud_httpc:request(MetaDataPath, get, Headers, <<>>, Timeout, Config)).

get_instance_metadata(ItemPath, Config, Token) ->
MetaDataPath = "http://" ++ ec2_meta_host_port() ++ "/latest/meta-data/" ++ ItemPath,
Header = maybe_token_header(Token),
erlcloud_aws:http_body(erlcloud_httpc:request(MetaDataPath, get, Header, <<>>, erlcloud_aws:get_timeout(Config), Config)).


-spec get_instance_user_data() -> {ok, binary()} | {error, erlcloud_aws:httpc_result_error()}.
get_instance_user_data() ->
get_instance_user_data(erlcloud_aws:default_config()).
Expand All @@ -75,12 +84,17 @@ get_instance_user_data(Config) ->
%% <host:port> defaults to 169.254.169.254
%%
%%
get_instance_user_data(Config) ->
UserDataPath = ?IMDS_BASE_URL ++ "/latest/user-data/",
Headers = get_imds_headers(Config),
Timeout = erlcloud_aws:get_timeout(Config),
erlcloud_aws:http_body(erlcloud_httpc:request(UserDataPath, get, Headers, <<>>, Timeout, Config)).

get_instance_user_data(Config, Token) ->
UserDataPath = "http://" ++ ec2_meta_host_port() ++ "/latest/user-data/",
Header = maybe_token_header(Token),
erlcloud_aws:http_body(erlcloud_httpc:request(UserDataPath, get, Header, <<>>, erlcloud_aws:get_timeout(Config), Config)).


-spec get_instance_dynamic_data() -> {ok, binary()} | {error, erlcloud_aws:httpc_result_error()}.
get_instance_dynamic_data() ->
get_instance_dynamic_data(erlcloud_aws:default_config()).
Expand All @@ -96,12 +110,73 @@ get_instance_dynamic_data(ItemPath, Config) ->
%%%---------------------------------------------------------------------------
-spec get_instance_dynamic_data( ItemPath :: string(), Config :: aws_config(), Token :: undefined | binary() ) -> {ok, binary()} | {error, erlcloud_aws:httpc_result_error()}.
%%%---------------------------------------------------------------------------
get_instance_dynamic_data(ItemPath, Config) ->
DynamicDataPath = ?IMDS_BASE_URL ++ "/latest/dynamic/" ++ ItemPath,
Headers = get_imds_headers(Config),
Timeout = erlcloud_aws:get_timeout(Config),
erlcloud_aws:http_body(erlcloud_httpc:request(DynamicDataPath, get, Headers, <<>>, Timeout, Config)).

%%%---------------------------------------------------------------------------
-spec get_instance_dynamic_data( ItemPath :: string(), Config :: aws_config(), Token :: undefined | binary() ) -> {ok, binary()} | {error, erlcloud_aws:httpc_result_error()}.
%%%---------------------------------------------------------------------------
get_instance_dynamic_data(ItemPath, Config, Token) ->
DynamicDataPath = "http://" ++ ec2_meta_host_port() ++ "/latest/dynamic/" ++ ItemPath,
Header = maybe_token_header(Token),
erlcloud_aws:http_body(erlcloud_httpc:request(DynamicDataPath, get, Header, <<>>, erlcloud_aws:get_timeout(Config), Config)).

%%%---------------------------------------------------------------------------
%% @doc Get or refresh IMDSv2 token from metadata service
%% Token is cached in application environment with timestamp
%% Refreshes if token is older than 3 hours to prevent expiration
%%%---------------------------------------------------------------------------
-spec get_imds_token(aws_config()) -> {ok, string()} | {error, any()}.
get_imds_token(Config) ->
case application:get_env(erlcloud, ?ERLCLOUD_TOKEN_CACHE_KEY) of
{ok, {Timestamp, Token}} ->
CurrentTime = erlang:system_time(second),
Age = CurrentTime - Timestamp,
if
Age < ?IMDS_TOKEN_REFRESH_THRESHOLD ->
{ok, Token};
true ->
fetch_new_imds_token(Config)
end;
undefined ->
fetch_new_imds_token(Config)
end.

%%%---------------------------------------------------------------------------
%% @doc Fetch a new IMDSv2 token and cache it
%%%---------------------------------------------------------------------------
-spec fetch_new_imds_token(aws_config()) -> {ok, string()} | {error, any()}.
fetch_new_imds_token(Config) ->
URL = ?IMDS_BASE_URL ++ "/latest/api/token",
Headers = [{"X-aws-ec2-metadata-token-ttl-seconds",
integer_to_list(?IMDS_TOKEN_TTL)}],
Timeout = erlcloud_aws:get_timeout(Config),
case erlcloud_httpc:request(URL, put, Headers, <<>>, Timeout, Config) of
{ok, {{200, _}, _, Body}} ->
Token = binary_to_list(Body),
CurrentTime = erlang:system_time(second),
application:set_env(erlcloud, ?ERLCLOUD_TOKEN_CACHE_KEY, {CurrentTime, Token}),
{ok, Token};
_ ->
{error, no_token}
end.

%%%---------------------------------------------------------------------------
%% @doc Get headers for IMDS requests with IMDSv2 token if available
%% Falls back to empty headers (IMDSv1) if token fetch fails
%%%---------------------------------------------------------------------------
-spec get_imds_headers(aws_config()) -> [{string(), string()}].
get_imds_headers(Config) ->
case get_imds_token(Config) of
{ok, Token} ->
[{"X-aws-ec2-metadata-token", Token}];
{error, _} ->
[] % Fallback to IMDSv1
end.

%%%------------------------------------------------------------------------------
%%% Internal functions.
%%%------------------------------------------------------------------------------
Expand Down
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