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Add instance association to Docker containers. #59

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igorpeshansky merged 2 commits into from
Feb 26, 2018
Merged

Add instance association to Docker containers. #59

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71e4c9c
Add instance association to Docker containers.
igorpeshansky Feb 22, 2018
f8040ea
Rename variable.
igorpeshansky Feb 25, 2018
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2 changes: 1 addition & 1 deletion src/Makefile
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Expand Up @@ -7,7 +7,7 @@ SUBMODULE_DIRS=$(CPP_NETLIB_DIR) $(YAML_CPP_DIR)

SED_I=/usr/bin/env sed -i
CMAKE=cmake
CXXFLAGS=-std=c++11 -g -DENABLE_KUBERNETES_METADATA -I$(CPP_NETLIB_DIR) -I$(YAML_CPP_DIR)/include
CXXFLAGS=-std=c++11 -g -DENABLE_DOCKER_METADATA -DENABLE_KUBERNETES_METADATA -I$(CPP_NETLIB_DIR) -I$(YAML_CPP_DIR)/include
LDFLAGS=-L$(CPP_NETLIB_LIBDIR) -L$(YAML_CPP_LIBDIR)
LDLIBS=-lcppnetlib-uri -lcppnetlib-client-connections -lboost_program_options \
-lboost_system -lboost_thread -lpthread -lyajl -lssl -lcrypto -lyaml-cpp
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164 changes: 110 additions & 54 deletions src/docker.cc
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Expand Up @@ -17,9 +17,11 @@
#include "docker.h"

#include "local_stream_http.h"
#include <boost/algorithm/string/join.hpp>
#include <boost/network/protocol/http/client.hpp>
#include <chrono>

#include "instance.h"
#include "json.h"
#include "logging.h"
#include "resource.h"
Expand All @@ -32,16 +34,91 @@ namespace google {
namespace {

#if 0
constexpr const char docker_endpoint_host[] = "unix://%2Fvar%2Frun%2Fdocker.sock/";
constexpr const char docker_api_version[] = "1.23";
constexpr const char kDockerEndpointHost[] = "unix://%2Fvar%2Frun%2Fdocker.sock/";
constexpr const char kDockerApiVersion[] = "1.23";
#endif
constexpr const char docker_endpoint_path[] = "/containers";
constexpr const char kDockerEndpointPath[] = "/containers";
constexpr const char kDockerContainerResourcePrefix[] = "container";
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@supriyagarg supriyagarg Feb 24, 2018

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Perhaps use a more descriptive prefix like "docker_container" to differentiate from "k8s_container" and "gke_container"

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@igorpeshansky igorpeshansky Feb 24, 2018

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Unfortunately, this string is user-visible, and we're already stuck with it. I'm just moving it from a hard-coded string into a constant.


}

DockerReader::DockerReader(const MetadataAgentConfiguration& config)
: config_(config), environment_(config) {}

MetadataUpdater::ResourceMetadata DockerReader::GetContainerMetadata(
const json::Object* container, Timestamp collected_at) const
throw(json::Exception) {
const std::string zone = environment_.InstanceZone();

const std::string id = container->Get<json::String>("Id");
// Inspect the container.
try {
json::value raw_container = QueryDocker(
std::string(kDockerEndpointPath) + "/" + id + "/json");
if (config_.VerboseLogging()) {
LOG(INFO) << "Parsed metadata: " << *raw_container;
}

const json::Object* container_desc = raw_container->As<json::Object>();
const std::string name = container_desc->Get<json::String>("Name");

const std::string created_str =
container_desc->Get<json::String>("Created");
Timestamp created_at = rfc3339::FromString(created_str);

const json::Object* state = container_desc->Get<json::Object>("State");
bool is_deleted = state->Get<json::Boolean>("Dead");

const MonitoredResource resource("docker_container", {
{"location", zone},
{"container_id", id},
});

json::value instance_resource =
InstanceReader::InstanceResource(environment_).ToJSON();

json::value raw_metadata = json::object({
{"blobs", json::object({
{"association", json::object({
{"version", json::string(config_.MetadataIngestionRawContentVersion())},
{"raw", json::object({
{"infrastructureResource", std::move(instance_resource)},
})},
})},
{"api", json::object({
{"version", json::string(config_.DockerApiVersion())},
{"raw", std::move(raw_container)},
})},
})},
});
if (config_.VerboseLogging()) {
LOG(INFO) << "Raw docker metadata: " << *raw_metadata;
}

const std::string resource_id = boost::algorithm::join(
std::vector<std::string>{kDockerContainerResourcePrefix, id},
config_.MetadataApiResourceTypeSeparator());
const std::string resource_name = boost::algorithm::join(
// The container name reported by Docker will always have a leading '/'.
std::vector<std::string>{kDockerContainerResourcePrefix, name.substr(1)},
config_.MetadataApiResourceTypeSeparator());
return MetadataUpdater::ResourceMetadata(
std::vector<std::string>{resource_id, resource_name},
resource,
#ifdef ENABLE_DOCKER_METADATA
MetadataAgent::Metadata(config_.MetadataIngestionRawContentVersion(),
is_deleted, created_at, collected_at,
std::move(raw_metadata))
#else
MetadataAgent::Metadata::IGNORED()
#endif
);
} catch (const QueryException& e) {
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@bmoyles0117 bmoyles0117 Feb 24, 2018

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Just a thought, now that we know what we know with the cpp-netlib, and that non 200 responses aren't actually throwing exceptions, the reason for this is more likely to be an issue with the docker daemon or the server it's running, not that the container disappears.

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@igorpeshansky igorpeshansky Feb 25, 2018

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Yes, I plan to fix status code handling in a subsequent PR, but it would be easier with this refactoring submitted.

throw json::Exception("Container " + id +
" disappeared before we could inspect it");
}
}

std::vector<MetadataUpdater::ResourceMetadata>
DockerReader::MetadataQuery() const {
if (config_.VerboseLogging()) {
Expand All @@ -50,77 +127,56 @@ std::vector<MetadataUpdater::ResourceMetadata>
const std::string zone = environment_.InstanceZone();
const std::string docker_endpoint(config_.DockerEndpointHost() +
"v" + config_.DockerApiVersion() +
docker_endpoint_path);
kDockerEndpointPath);
const std::string container_filter(
config_.DockerContainerFilter().empty()
? "" : "&" + config_.DockerContainerFilter());
http::local_client client;
http::local_client::request list_request(
docker_endpoint + "/json?all=true" + container_filter);
std::vector<MetadataUpdater::ResourceMetadata> result;
try {
http::local_client::response list_response = client.get(list_request);
json::value parsed_list = QueryDocker(
std::string(kDockerEndpointPath) + "/json?all=true" + container_filter);
Timestamp collected_at = std::chrono::system_clock::now();
if (config_.VerboseLogging()) {
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@bmoyles0117 bmoyles0117 Feb 24, 2018

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Why did you remove this verbose logging? Is it only helpful during development?

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@igorpeshansky igorpeshansky Feb 25, 2018

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This verbose logging is now part of QueryDocker.

LOG(INFO) << "List response: " << body(list_response);
}
json::value parsed_list = json::Parser::FromString(body(list_response));
if (config_.VerboseLogging()) {
LOG(INFO) << "Parsed list: " << *parsed_list;
}
const json::Array* container_list = parsed_list->As<json::Array>();
for (const json::value& element : *container_list) {
for (const json::value& raw_container : *container_list) {
try {
const json::Object* container = element->As<json::Object>();
const std::string id = container->Get<json::String>("Id");
// Inspect the container.
http::local_client::request inspect_request(docker_endpoint + "/" + id + "/json");
http::local_client::response inspect_response = client.get(inspect_request);
if (config_.VerboseLogging()) {
LOG(INFO) << "Inspect response: " << body(inspect_response);
}
json::value parsed_metadata =
json::Parser::FromString(body(inspect_response));
if (config_.VerboseLogging()) {
LOG(INFO) << "Parsed metadata: " << *parsed_metadata;
}

const MonitoredResource resource("docker_container", {
{"location", zone},
{"container_id", id},
});

const json::Object* container_desc = parsed_metadata->As<json::Object>();
const std::string name = container_desc->Get<json::String>("Name");

const std::string created_str =
container_desc->Get<json::String>("Created");
Timestamp created_at = rfc3339::FromString(created_str);

const json::Object* state = container_desc->Get<json::Object>("State");
bool is_deleted = state->Get<json::Boolean>("Dead");

const std::string resource_id =
std::string("container") + config_.MetadataApiResourceTypeSeparator() + id;
// The container name reported by Docker will always have a leading '/'.
const std::string resource_name =
std::string("container") + config_.MetadataApiResourceTypeSeparator() + name.substr(1);
result.emplace_back(std::vector<std::string>{resource_id, resource_name},
resource,
MetadataAgent::Metadata(config_.DockerApiVersion(),
is_deleted, created_at, collected_at,
std::move(parsed_metadata)));
const json::Object* container = raw_container->As<json::Object>();
result.emplace_back(GetContainerMetadata(container, collected_at));
} catch (const json::Exception& e) {
LOG(ERROR) << e.what();
continue;
}
}
} catch (const json::Exception& e) {
LOG(ERROR) << e.what();
} catch (const boost::system::system_error& e) {
LOG(ERROR) << "Failed to communicate with " << docker_endpoint << ": " << e.what();
} catch (const QueryException& e) {
// Already logged.
}
return result;
}

json::value DockerReader::QueryDocker(const std::string& path) const
throw(QueryException, json::Exception) {
const std::string endpoint(config_.DockerEndpointHost() +
"v" + config_.DockerApiVersion() +
path);
http::local_client client;
http::local_client::request request(endpoint);
if (config_.VerboseLogging()) {
LOG(INFO) << "QueryDocker: Contacting " << endpoint;
}
try {
http::local_client::response response = client.get(request);
#ifdef VERBOSE
LOG(DEBUG) << "QueryDocker: Response: " << body(response);
#endif
return json::Parser::FromString(body(response));
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@bmoyles0117 bmoyles0117 Feb 24, 2018

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This is the area I'm referring to for non 200 responses. This is likely work for the future, but we should be checking for the response status code, instead of just assuming we're returning the right response based on ANY response at all.

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@igorpeshansky igorpeshansky Feb 25, 2018

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Yes, I have a PR ready to go with a fix, just waiting to rebase on this refactoring.

} catch (const boost::system::system_error& e) {
LOG(ERROR) << "Failed to query " << endpoint << ": " << e.what();
throw QueryException(endpoint + " -> " + e.what());
}
}

}
19 changes: 19 additions & 0 deletions src/docker.h
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Expand Up @@ -33,6 +33,25 @@ class DockerReader {
std::vector<MetadataUpdater::ResourceMetadata> MetadataQuery() const;

private:
// A representation of all query-related errors.
class QueryException {
public:
QueryException(const std::string& what) : explanation_(what) {}
const std::string& what() const { return explanation_; }
private:
std::string explanation_;
};

// Issues a Docker API query at a given path and returns a parsed
// JSON response. The path has to start with "/".
json::value QueryDocker(const std::string& path) const
throw(QueryException, json::Exception);

// Given a container object, return the associated metadata.
MetadataUpdater::ResourceMetadata GetContainerMetadata(
const json::Object* container, Timestamp collected_at) const
throw(json::Exception);

const MetadataAgentConfiguration& config_;
Environment environment_;
};
Expand Down